Merry Christmas! (& Memes & Mirror Neurons)

So this is my last post before I’ll be heading home over the holidays.

As I tried to show in this post, it seems that the ability to imitate is crucial for learning a language. Most importantly, it also seems to be a major foundation of all human culture.

There is whole lot of research done in this field and there are hot discussions about the relationship between mirror neurons, imitation, Theory of Mind, language acquisition, language evolution, human cultural evolution, etc.

Memetics, for example, sees our ability to adopt cultural and cognitive patterns of behavior as mediated by our imitative abilities (Blackmore 2007). In 2005 Nick Chater and Susan Hurley published and edited Perspectives on Imitation: From Neuroscience to Social Science, a two volume monstrosity with 1024 pages covering Mechanisms of Imitation, Imitation in Animals, Imitation and Human Development as well as Imitation and Culture, This underlines the renewed appreciation of the importance of imitation as a fundamental property of cognition, instead of an uninteresting low-level phenomenon. (McEwen 2007)

The notion of a link between human culture and cognition on the one hand, and imitation and learning on the other, is of course not new – as we have seen in the passage of Puttenham’s Arte of Poesie I quoted in my last post on imitation. If you look up “imitative” in the OED, you find a 1777 quote by David Hume, who wrote that

“The human mind is of a very imitative nature”

as well as the assessment that

“At present, we are become an imitative, not to say a mimic, race” (in Gifford’s 1827 introduction to the plays of John Ford).

We can trace this notion as far back as to Aristotle, who in his Poetics, claimed that mimesis, the representation or imitation of a state in the world in the form of action, art, or speech, is a fundamental property of human cognition. Interestingly, he describes imitation as an “instinct of our nature” and writes that:

“the instinct of imitation is implanted in man from childhood, one difference between him and other animals being that he is the most imitative of living creatures, and through imitation learns his earliest lessons;”

As it seems, Aristotle’s assessment is indeed backed up by behavioral evidence. 30 years ago, Meltzoff and Moore (1977) found that 12 to 21-day old infants were able to imitate the experimenter’s facial gestures of mouth opening, lip protrusion and, tongue protrusion, as well as manual gestures such as the opening of the hand. In a follow-up study, they showed that even newborns who are less than 72 hours old are able to imitate these gestures (Meltzoff & Moore 1989). Interestingly, this tendency seems to disappear between two and three months of age. This is probably explained by the fact that autonomously controlled, spontaneus face-to-face social interaction (as a baby smiling at her mother, for example) kicks in around this time and infants start to communicate intentionally. (Myowa-Yamakoshi et al. 2004: 441)

Now is this a uniquely human trait?

Quite astonishingly, Myowa-Yamakoshi et al. (2004) found that chimpanzees who are less than 7 days old are also able to imitate the gestures of tongue protrusion, mouth opening, and lip protrusion.

As in humans, this tendency disappeared at two months of age. The authors conclude that
“like human neonates, chimpanzee neonates are born with the ability to match visually perceived oral gestures with a proprioceptive motor schemes .“ (Myowa-Yamakoshi et al. 2004: 440).

So what about other primates? Previously it was thought that only humans and apes posses these neonatal skills, but it seems that at 3 days of age, rhesus macaques are able to imitate lip smacking and tongue protrusion (Ferrari et al. 2006), facial gestures which later become important in social interaction (Gross 2006)

However, the macaques showed this behavior only a few days after birth and after that it vanished. This may be due the fact that motor as well as cognitive development in macaques is much more rapid in macaques than in the higher apes. It thus seems that the more advanced human imitation capacities built on these imitative foundations that must have been present at the time our lineage split from that of macaques, namely 25 million years ago.
Interestingly, macaques were the first species in which mirror neurons – neurons that fire both during the performance as well as during the observation of an action – were found, and hopefully there will be more studies on the neural basis of imitation in macaques.

Quite Remarkably, adult macaques are also able to notice when someone else is imitating their actions (e.g. a human experimenter), but it is unclear whether they are able to grasp the fact that the experimenter is intentionally imitating them, or if they just recognize it implicitly (Paukner et al. 2005). In the second case, the macaques would just exhibit this knowledge via metacognition, i.e. the awareness of some inner state, something which macaques seem to be able to do.
Evidence for metacognition in macaques comes from research done by H.S. Terrace and his team, who taught their macaques a matching game, and then offered them the options to either play the game and get some food if they won and nothing if they lost, or the option to not play the game and get less food. Interestingly, sometimes the macaques chose the latter, option, and sometimes they chose the former, but if they chose the first option, they performed pretty well, indicating that the macaques had a means of assessing how accurate they were at getting the game right. In another experimental setting, macaques also learned to ask for hints if they otherwise had to solve the problem by trial and error, again indicating that they had some metacognitive means of assessing what they knew and what they didn’t (Kornell et al. 2007).
It is much more questionable if macaques exhibit metarepresentation, i.e. the awareness of mental states of others (Hurford 2007: 35)

This of course taps into the discussion of which primates exhibit a Theory of Mind, or an awareness of the mental states of others, and whether the transition from nonhuman to human minds should be seen as continuous or discontinuous. The two main camps in this debate are that of Povinelli and his colleagues on the one side, who argue that nonhuman primates do not exhibit abstract inferences of others mental states, and that there is a qualitative gap between human and nonhuman cognition (Povinelli & Vonk 2003), and Tomasello and his team on the other side, who argue that chimpanzees are able to understand some psychological states to a certain degree, and that human cognition should be seen as much more continuous (Tomasello et al. 2003). It seems as if Povinelli and his colleagues are just about to launch their next major attack (to be publish in the journal Behavioral and Brain Sciences in 2008) awe-inspiringly called “Darwin’s mistake: Explaining the discontinuity between human and nonhuman minds” . As BBS consists of the target article along with 25 or so commentaries other researchers, I’m really interested in how this will turn out.

For now it is quite interesting enough (and also somewhat amusing) how both parties assess the importance of the debate:

Whereas Tomasello et al. (2003) claim that:

“At issue is no less than the nature of human cognitive uniqueness” (Tomasello et al. 2003: 156)

Povinelli et al. take a much more relaxed stance:

"the idea that theory of mind is the ‘holy grail’ of comparative cognition needs to be abandoned. Neither chimpanzees nor evolutionary theory will be insulted if the very idea of ‘mental states’ turns out to be an oddity of our species’ way of understanding the social world.“ (Povinelli et al. 160)

Dang, I still haven’t posted about either the Lyons et al. (2007) paper or the genetic differences between humans and chimpanzees. But I will do so next year. Promise. Cross my Heart and Hope to Die. As an apology, here’s a link to a great song by Jonathan Coulton, performed live in front of an audience of (judging by the chorus) zombies. Gotta love that.

So merry Christmas & Happy New Year, and see you in 2008.

References:

Blackmore, Susan. 2007. “Those dreaded memes: The advantage of memetics over “symbolic inheritance.” Behavioral and Brain Sciences 30.4: 365-366.

Ferrari PF, Visalberghi E, Paukner A, Fogassi L, Ruggiero A, et al. (2006) Neonatal imitation in rhesus macaques. PLoS Biol 4(9): e302. DOI: 10.1371/journal.pbio.0040302

Gross L (2006) Evolution of Neonatal Imitation. PLoS Biol 4(9): e311 doi:10.1371/journal.pbio.0040311

Hurford, James M. 2007. The Origins of Meaning: Language in the Light of Evolution. Oxford: OUP.

Kornell, Nate, Son, Lisa K. and Herbert S. Terrace. 2007. “Transfer of Metacognitive Skills and Hint Seeking in Monkeys. Psychological Science” 18.1: 64-71.

McEwen, Fiona. 2007. “Review: Perspectives on Imitation: From Neuroscience to Social Science.” Mind & Language, 22.2 April : 207–213

Meltzoff AN, Moore MK .1977. Imitation of facial and manual gestures by human neonates. Science 198: 75–78.

Meltzoff AN, Moore MK (1989) Imitation in newborn infants: Exploring the range of gestures imitated and the underlying mechanisms. Developmental Psychology 25: 954–962

Myowa-Yamakoshi M, Tomonaga M, Tanaka M, Matsuzawa T .2004. “Imitation in neonatal chimpanzees (Pan troglodytes).” Developmental Science 7: 437–442

Paukner A, Borelli E, Visalberghi E, Anderson JR, Ferrari PF (2005) Macaques (Macaca nemestrina) recognize when they are being imitated. Biology Letters 1: 219–222.

Povinelli, D.J. and Vonk. J. (2003) Chimpanzee minds: Suspiciously human? Trends in Cognitive Sciences, 7.4, 157–160.

Tomasello, Michael, Josep Call and Brian Hare. 2003. Chimpanzees understand psychological states – the question is which ones and to what extent. Trends in Cognitive Sciences, 7- 153-156.

Links

moar funny pictures

Sorry, no time for a real post today. I hope I'll be able to make up for it on Thursday.
Instead, here's a small compilation of cool links:

For those who enjoyed (or at least read and tolerated) my three to five part discussion of Baboon Metaphyiscs: Dorothy Cheney and Robert Seyfarth give an Interview over at NPR.

On Cheney & Seyfarth’s Lab website you can listen to baboon vocalizations and the famous referential Vervet alarm calls. It is quite interesting to think that some distant precursor of language could’ve actually sounded something like this.

In addition, over at the website of Marc Hauser’s Lab there are also some videos and recordings of vervet, cotton-top tamarin, rhesus macaques, and chimpanzees.

One especially interesting piece is a video of a macaque apparently investigating his image in the mirror

Maybe it’s old news, but some of you may still not know the Chomsky Garden Gnome

To complete the Hauser et al. (2002) pack, on W. Tecumseh Fitch’s site you can listen to Hoover the talking seal

and you can also listen to some very nice songs he has written.

My favorite is the fantastic and incredibly funny “I Don’t Believe in Evolution”

Go check it out!

Speaking of Language Evolution, The University of Edinburgh's Language Evolution and Computation has a very nice and extensive bibliography which it is really worth checking out.

Finally A while back, Carl Zimmer linked to this New Scientists Video of a Wasp which can transform cockroaches into zombies How cool is that? (Warning, some people may find the footage a bit gross)

Carl Zimmer also linked to Derek Lyon's (whose paper I will blog about on thursday) new and impressive website, Hello Felix, which might be of interest to those of you who want to know more about imitation in human children and chimpanzees.

That's all for today, see you on Thursday.

Well, Mimes Still Suck

So in my last post I wrote about the importance of vocal imitation for the evolution of language. According to Hauser et al. (2002), it is one of the most important species-specific, but not language-specific components that make up the faculty of language in the broad sense (FLB), as opposed to the faculty of language in the narrow sense, (FLN), which they equate with the

"core computational mechanisms of recursion as they appear in narrow syntax and the mappings to the interfaces [of the conceptual-intentional system (e.g. vocal imitation, sound-pattern discrimination, language perception and production, etc.) and the sensory-motor system(e.g. Theory of Mind, nonlinguistic conceptual representations, voluntary control over signal production, etc.) - and whatever you think should be seen as a part of it, Hauser et al. don't care]" (Hauser et al. 2002: 1573)

Whatever that is supposed to mean.
Hauser et al. also list

"Imitation as a rational, intentional system" (Hauser et al. 2002: 1573)

as a component of the conceptual-intentional system, and cite

"Comparative studies of chimpanzees and human infants suggesting that only the latter read intentionality into action, and thus extract unobserved rational intent" (Hauser et al. 2002: 1573).This remark touches upon the messy theory of mind debate in the cognitive sciences and elsewhere. Hauser et al. seem to assume that there is an intrinsic link between some forms of imitation and the attribution of intent to the other. They report that chimpanzees seem to have only minimal visual-imitative capacities, and that there is almost no evidence for them in monkeys (Hauser et al. 2002: 1575). According to Hauser et al. this seems to confirm that non-human apes and monkeys are not able to attribute intentions to others.

However, it seems that chimpanzees at reading others behavioral programs, and predicting their future actions without needing to attribute mental states to con-specifics. (Byrne and Russon 1998) In general, just as language is not a monolithic whole, imitation probably is also a cognitive capacity consisting of various component parts. Byrne and Russon (1998) propose that Imitation is in fact a task that is hierarchically divided in separate forms of imitation, that is

1. Imitation as Goal Imitation (i.e. achieve the same result, e.g. eating a fruit, possibly in a roughly similar as someone before you).
   
2. Imitation at the Program Level (i.e. simulate the actions at a broad behavioral level, representing the organizational structure of an action, without imitating it in detail)
   
3. Impersonation, or "True Imitation" (i.e. simulate the other's motoric actions in detail)
   

According to Byrne and Russon (1998), all great apes are able to imitate behavior at the second level, and the use of "action level" imitation is primarily restricted to humans (although they speculate that in non-human great apes, this may be more a matter of motivation than ability), but only plays a minor role, because even such complex skills as the learning of language (e.g. sound production) are achieved on the program level because they do not actually imitate the physical sounds but the organizational structure of the sound system. However, they don't really come up with a good explanation why action level imitation exists in humans at all, and even doubt that it plays an important or even frequent role at all.

As Tomasello (1998) rightly criticizes, this largely downplays the role of shared human cultural and cognitive artifacts and the creative use to which they can put in order to facilitate new functional dimensions and therefore progress, and fails to explain what it is that is special about humans, and why cultural transmission in humans is so much more powerful than in other apes.
They also greatly underestimate the importance of the arbitrary, conventionalized nature of the (Saussurean) linguistic sign, which is crucial for the establishment of a successfully communicating group of agents (Which is also why my blog's title alludes to this principle. I'll come back to this in a subsequent post)
I think it is interesting to contrast Byrne and Russon's model with evidence of so-called conformity bias in chimpanzees.
Whiten et al. (2005) taught two distinct tool-use techniques to two high-ranking female chimpanzees, and then brought them back to their groups. 30 of 32 chimpanzees adopted the female chimpanzees technique. Some chimpanzee at first discovered different means of tool-use, which could be explained in terms of broad organizational imitation, but later also adopted the predominating technique of their group, even if they were able to use both techniques and both very equally successful. If chimpanzees would act only at a broad behavioral level, then this effect surely wouldn’t have occurred. Thus, there is evidence that even in chimpanzees there is the convergence of complex behavioral patterns (we could even call them ‘memes’ if we felt like it) to a cultural norm. Thus, such tendencies must have a deeper evolutionary heritage than assumed before.
Furthermore, Byrne and Russon write that

"We suspect, however, that action level imitation is less common in children than it seems, and that, often, children’s “imitation” may reflect response facilitation." (Byrne and Russon 1998: 683)"

This, however, is clearly refuted by experiments done by Lyons et al. (2007), which I will describe in my next post. (In the meantime, however, you should rather go read Carl Zimmer's heartening and much more enjoyable blog post and article in the New York Times about the fate of his daughter in comparative tests between human children and chimpanzees. )
Without question, Byrne and Russon's model is not able to give a complete theory of imitation, which is why I will look at some other approaches in my next post

References:

Byrne, Richard W and Anne E. Russon. 1998. “Learning by Imitation: a Hierarchical Approach.” Behavioral and Brain Sciences 21.5: 667-684

Hauser, Marc D., Noam Chomsky and W. Tecumseh Fitch 2002. “The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?” Science 298: 1569-1579.

Lyons, Derek E.. Andrew G. Young, and Frank C. Keil. 2007. “The Hidden Structure of Overimitation” PNAS 105.50: 19751–19756.

Tomasello, Michael. 1998. “Emulation learning and cultural learning.” Behavioral and Brain Sciences 21.5: 703-704.

Whiten, Andrew, Victoria Horner & Frans B. M. de Waal. 2005. “Conformity to Cultural Norms of Tool Use in Chimpanzees.” Nature 437: 737-740.

Oh, I Forgot Something

In my last post I wrote that two main approaches to comparing human and other animals’ cognition are ethological and genetic comparisons, but I think with such a statement I strongly downplayed the importance of anatomical features when comparing two species, such as the differences in brain anatomy (for a stake at this topic, see my earlier posts on brain evolution), and other features that bear a more indirect bearing on the structure of human cognition, yet it has a much stronger bearing on questions of human uniqueness.

These considerations are of course not exactly new. as early as in 1589, for example, George Puttenham wrote in his Arte of English Poesie that:

“Speach is not naturall to man sauing for his onely habilitie to speake, and that he is by kinde apt to vtter all his conceits with sounds and voyces diuersified many maner of wayes, by meanes of the many & fit instruments he hath by nature to that purpose, as a broad and voluble tong, thinne and mouable lippes, teeth euen and not shagged, thick ranged, a round vaulted pallate, and a long throte, besides and excellent capacitie of wit that maketh him more disciplinable and imitatiue then any other creature […].”

I will stick with this example because language evolution is this blog’s main topic.
What I find interesting in this paragraph is that Puttenham actually directs attention to a lot of physiological features that are acknowledged by modern linguists and phoneticians to be crucial for the production of speech. As Jean Aitchision puts it, we are “The Articulate Mammal” (1998), and many of her observations actually concur with that of Puttenham.
Just as he does she stresses the difference between the long thin tongues of monkey and the muscular, thick and mobile tongues of humans, which allows them to vary the size of the oral cavity, and thus allows the pronunciation of a great range of vowels.
She also stresses the fact that the muscles in the lips of humans are more intricately interlaced and more developed than the muscles in the lips of other primates. Aitchision also observes that the regularity of human teeth is not needed for eating but probably for articulatory purposes. (Aitchison 1998: 48f., Lieberman 2007: 40-47 , Fitch 2005: 198f.)

I doubt that Puttenham was the first to notice the importance of the specially structured and descended larynx of humans for speech, but he definitely wasn’t the last. Whereas in most mammals, simultaneous breathing and swallowing is possible, humans (or at least those who aren’t babies anymore), don’t posses this ability because their larynx lies too low to be engaged into the nasal passages. (Fitch 2000: 260)
This anatomical change expands the vocal repertoire of humans significantly and can be seen as “a key innovation in the evolution of speech” (Fitch 2000: 261) because it enabled us to form highly discriminable different phonetic sounds (“formant patterns”) (Fitch 2000:261),
However, it has lately been discovered that animals exhibit a remarkable plasticity in regards to the lowering of the larynx during vocalization (for a example, a dog bark) Furthermore, the descension of the larynx doesn’t seem to be unique to humans, and is also found in lions, koalas, and deer. (Fitch 2005: 199).

This has led some researchers, such as Tecumseh Fitch, to suggest that this shared property is an instance of convergent evolution and thus evolved for a different purpose than speech production, namely size exaggeration, the function the descension of the larynx fulfills, for example, in deer (Fitch and Reby 2001, Fitch 2005).
In this view, the descension of the larynx was prior to speech and was only later co-opted for language. The first fully modern human speech anatomy is dated to 50,000 years ago, and is missing in earlier humans as well as Neanderthals. (Lieberman 2007). This still fits with the a scenario in which the speech tract was only later adapted and further shaped for language, and it definitely shows that language/speech is a driving force in human evolution, given the long evolutionary trajectory it has had.

But what then, is special to speech? Again it seems that Puttenham was on the right track. Hauser et al. (2002), for example, also stress the importance of vocal imitation in language learning and production. Whereas dolphins, whales, seals, songbirds, parrots, hummingbirds and some other species seem to share humans’ aptness regarding vocal imitation, it seems that in other primates this trait is either absent or only exists in a rather rudimental form (Hauser et al. 2002, Fitch 2000, Fitch 2005).
This is supported for example by evidence from cross-fostered Japanese/rhesus macaques. Although both species have a very similar social structure, their vocalizations are quite different in some context. Whereas juvenile Japanese macaques give clear cooing sounds when playing, rhesus macaques give gruffy grunts in the same situation. Did the Japanese macaques growing up in the Rhesus macaque adopt the vocalizations of their foster species? What about the Rhesus macaques growing up among Japanese Macaques?
Interestingly, although they are in fact able to produce such sounds (and do so in other contexts), the Japanese Macaque splaying with Rhesus macaques gave coos whereas their playmates gave gruffs. The same lack of vocal adaptation could be seen in the cross-fostered rhesus macaques. Certain calls in the macaques seem to be genetically bound to specific contexts(Cheney & Seyfarth 2007: 225, Owren et al. 1993), something which clearly isn’t the case with humans (otherwise there wouldn’t be 250 different languages spoken alone in Brooklyn, for example).

So the case Hauser et al. make for vocal imitation seems quite a strong one. Yet, as they themselves acknowledge, the question what vocal imitation evolved for is still hotly debated. There is still further evidence that supports the notion that vocal imitation is a more crucial component that led to human language than mere voluntary vocal control per se.
As we have seen, in some situations primate and generally animal signaling is closely bound to specific contexts. However, there are other situations where call production is much more plastic and seems to be much more under voluntary control.

One example is a study by Hihara et al. (2003), in which they trained macaques to use a rake in order to retrieve food, and subsequently brought them to either request the food directly, or request the rake, via cooing (Something the monkey is probably inclined to utter naturally in the context of food.) Astonishingly, the monkeys came up with two distinct calls all on their own, one for requesting the rake, the other for requesting for food (Cheney & Seyfarth 2007: 227, Hihara et al. 2003).
An even more intriguing example of signal transformation (albeit not in the auditory modality), called schematization of action, is the following: (Which I took from Hurford 2007, who took it from Gomez 2005 – yeah, recursion rocks!)

“Thorndike (1898) found that cats that were released from a puzzle-box upon performance of an arbitrarily chosen action (e.g., licking their paw), instead of by the accidental activation of the releasing device, tended to develop an abridged, sketched-out version of the relevant behaviour — something like a “gesture” of paw-licking“ (Gomez 2005: 93, Hurford 2007: 199,)

Of course, Puttenham wasn’t only referring to vocal imitation. In fact, things lie a bit differently when we speak about general imitation, and I’ll discuss some of the evidence on human vs. non-human imitation in my next post.

References:

Aitchison, Jean. 1998. The Articulate Mammal. An Introduction toPsycholinguistics. London / New York: Routledge.

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. University of Chicago Press, Chicago

Fitch W. Tecumseh. 2000. The evolution of speech: a comparative review. Trends in Cognitive Sciences. 4: 258 – 267.

Fitch, W. Tecumseh. 2005. “The Evolution of Language: A Comparative Review” P Biology and Philosophy 20: 193–230

Fitch, W. Tcusmeh and David Reby. 2001. “The descended larynx is not uniquely human.” Proclamations of the Royal Society B: Bioliogical Sciences 268: 1669 – 1675.

Gómez, Juan Carlos. 2005. “Requesting gestures in captive monkeys and apes: Conditioned responses or referential behaviours?“ Gesture 5.1/2: 91-105.

Hauser, Marc D., Noam Chomsky and W. Tecumseh Fitch 2002. “The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?” In: Science 298, 1569-1579

Hihara, Sayaka, HirokoYamada, Atsushi Iriki, and Kazuo Okanoya. 2003. “Spontaneous vocal differentiation of coo-calls for tools and food in Japanese monkeys” Neuroscience Research 45.4

Hurford, James M. 2007. The Origins of Meaning: Language in the Light of Evolution. Oxford: OUP.

Lieberman, Phillip. 2007. “The Evolution of Speech: Its Anatomical and Neural Bases.” Current Anthropology 48.1: 39-66.

Owren MJ, Dieter JA, Seyfarth RM, Cheney DL.. 1993 “Vocalizations of rhesus (Macaca mulatta) and Japanese (M. fuscata) macaques cross-fostered between species show evidence of only limited modification “ Developmental Psychobiology 26.7: 389-406.

Thorndike, Edward L. 1898. “Animal intelligence: An experimental study of the associative processes in animals.” Psychological Review: Series of Monograph Supplements, 2.4: 1-109.

A Zombie’s Inquiry Into the Evolution of His Most Favorite Meal IV: Genes that Code for Tasty brains

There are two main approaches to look at the differences between humans and other non-human primates such as chimpanzees: ethological studies of animal behavior and their cognitive abilities (it looks like there is a difference between Cognitive Ethology, Comparative Ethology & Comparative Psychology, but as it seems this is more a matter of whether you emphasize the biological, cognitive science, or psychological aspect of behavior) and genomic comparisons.

On the side of genetic comparisons, we already have the sequenced genome of humans, chimpanzees, and macaques, which, somewhere in the relatively near future, the future, are to be joined by the genomes of Neanderthals, bonobos, (both sequenced by our friends at the Max Planck Institute for Evolutionary Anthropology - gosh! it would really have been a tremendous loss for science if its members had been eaten by zombies… So thanks for that George) gorillas, and gibbons. As Kambiz Kamrani pointed out over at primatology.net, the more primate genomes we get together, the better we are able to make out human specialness (as well as Chimpanzees-Specialness, Bonobo-Specialness, Gorilla-Specialness etc.), as well as the things we share with other primates, in terms of specific genes.
This may indeed help us ““to find out what being human is.” James Watson originally hoped this would be the result of the sequencing of the human genome. (Pennisi 2007: 218) but now, with an ever-growing genetic database, we somewhere in the future we may indeed be able “to trace back the evolutionary changes that occurred at various time points, leading from the common ancestors of the primate clade to Homo sapiens,” as Bruce Lahn puts it. (Pennisi 2007: 218). Researchers all over the world further plan on sequencing the genomes of the orangutan, the marmoset, the tarsier, the mouse lemur, the galago, the tree shrew as well as the lemur in order get an ever broadening picture of our evolutionary history, ultimately tracing back 83 million years of evolutionary time.
Within this comparative context, we of course may really see the “dawn of cognitive genetics” (Pinker 2001: 465). In the field of language evolution, for example, we may finally establish the genetic foundations and extensions that made human language possible. But at the moment, it seems as if there are still so much things that are maddeningly unclear, (and I as layman, naturally don’ understand anything about “regulatory sequences”, “junk DNA” and messy genetic differences at the molecular level…) so it’s definitely still a very long way until we can go beyond FOXP2, MPH1, and ASPM (not to speak of understanding even the exact roles of these genes.)

On the side of ethological studies, the methods employed and results obtained (which I describe in my last post) by Herman et al. (2007) clearly show interesting avenues of future research, and hint at a possible meeting point between the two approaches:

“A major avenue of future research is thus to use [the research methodologies employed by Herman et al.] to characterize the behavioral-cognitive phenotype of a wide variety of primate species. This could be done through systematic testing of carefully chosen representatives of the more than 50 genera of primates, which should then enable us to map out cladistically the evolution of primates’ most important cognitive skills at the level of both the phenotype and, ultimately, the genotype.” (Herman et al. 2007: 1365)

For our Zombie-Scientist George the main question remains: “Why are human brains so tasty ?” (let’s presume that in our Parallel zombieverse, the zombie-gourmet is only fond of human brains and not that of other non-human brains.) The Theory by which George now arrives looks like this: “The unique tastiness of human brains basically must boil down to some uniquely human genes (or genetic combinations or gene expressions)” That’s why I will lok a bit at the differences between human and chimp-genes in my next post.

References:

Hermann, Esther Josep Call, María Victoria Hernández-Lloreda, Brian Hare, and Michael Tomasello. 2007. “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis” Science 317: 1360-1366.

Pennisi, Elisabeth. 2007 “Genomicists Tackle The Primate Tree.” Science 316: 218-221.

Pinker, Steven. 2001. “Talk of genetics and vice versa“ Nature 413: 465-466

A Zombie’s Inquiry Into the Evolution of his Most Favorite Meal III: What are Humans Good at?

Except running away from poor, starving zombies, that is (– the Selfish Bastards!)

A while back Juan Uarigerika wrote an article in Seed magazine about language evolution. In it he proposed that maybe language is responsible for most of our especially human intelligence, as well as precursor for our more advanced sensorimotor capacities, and that in the end it could turn out that research into our cognitive architecture would come up with the formula ‘Finch + Chimp = Human.’ Uarigerika’s article is written, for a magazine, so it’s clear that he doesn’t really do much in order of presenting evidence and arguments in a really ‘scientific’ way but rather presents his ideas in a in a popular style, but still I think his proposal is quite problematic (Mark Liberman has written a nice rebuttal of Uarigerika’s reductionsit view over at Language Log)


moar funny pictures

A better way to study the differences between human and animal cognition effectively is to compare differences and similarities of certain cognitive traits and analyze how these may come about and how the cognitive function in question is enabled in the given organism.
In a massive comparative study, Hermann et al. (2007) had Chimpanzees, Orangutans and 2.5 year-old children perform various task and then evaluated and compared the species’ qualitatively differing performances. The tasks were divided into two “domains”, physical and social, each consisting of three “scales” (physical: space, quantitiy, causality; social: social learning, communication, theory of mind). Among the 20 tasks there were such things as “using a stick in order to retrieve a reward which is out of reach.” (causality), “Locating a reward.“ (space), “Solving a simple but not obvious problem by observing a demonstrated solution” (social learning), “Following an actor’s gaze direction to a target” or “Understanding what an actor intended to do (unsuccessfully” (both Theory of Mind).

On average, the results of humans and chimpanzees were very similar in the physical domain, and scored much higher than the orangutans. In the social domain, however, humans outperformed chimpanzees and orangutans by far. The non-human apes were right only half as often as the human children. This means that chimpanzees outcompete orangutans when it comes to things as causal reasoning and quantities, but are equally bad at imitating others or assessing their intentions. Whereas in the physical tasks chimps sometimes performed better than humans (e.g. Tracking of a reward after location changes or Using a stick in order to retrieve a reward which is out of reach, something where human children performed much worse than both chimps and orangutans), interestingly

“Children were better than both ape species at the three causality tasks in which a judgment must be made before manipulation or choice, whereas chimpanzees were better than children and orangutans at the one causality task involving active tool use.” (Hermann et al. 2007:1362)

as well as in regard to inhibitory control, which could partly be due to the prominence and dominance of prefrontal circuitry in the human brain and its importance in cognitive control— “the ability of the brain to coordinate processing mong its millions of neurons in order to direct them toward future goals.” (Miller et al. 2002: 1131) — which I alluded to in my earlier posts.

Chimps and orangutans both performed a little better than human children when it came to “Producing communicative gestures in order to retrieve a hidden reward.”, which was the only social domain task in which the difference between the human and non-human primates wasn’t significant. The authors conclude that

“the current results provide strong support for the cultural intelligence hypothesis that human beings have evolved some specialized social-cognitive skills (beyond those of primates in general) for living and exchanging knowledge in cultural groups: communicating with others, learning from others, and “reading the mind” of others in especially complex ways“ (Hermann et al. 2007: 1365).

But they caution against the conclusion that social intelligence as a whole, or a “Theory of Mind-module” is the distinctive property separating humans, chimps and orangutans. Instead, taking into account that human children were better than chimps in causality tasks that didn’t include the active manipulation of tools, they speculate that

“what may be distinctive is the ability to understand unobserved causal forces in general, including (as a special case) the mental states of others as causes of behavior. Even in this case, however, it is a plausible hypothesis that understanding hidden causal forces evolved first to enable humans to understand the mental states of other persons, and this generalized only later to the physical domain.”

Which fits well with the evidence that humans are especially good at displaced mental and conceptual simulation (Miller et al. 2002, Barsalou 2005) and such things as mental time travel (Gilbert & Wilson 2007).
In my next post I will expand a bit on complementary approaches to comparing human and other non-human primate cognition and differences in general.

References:

Barsalou, Lawrence W. 2005. “Continuity of the conceptual system across species.” Trends. Cog. Sc. 9.7: 309-311.


Gilbert, Daniel T. and Timothy D. Wilson. 2007. “Prospection: Experiencing the Future.” Science 317: 1351-1354.

Hermann, Esther Josep Call, María Victoria Hernández-Lloreda, Brian Hare, and Michael Tomasello. 2007. “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis” Science 317: 1360-1366.


Miller, Earl K., David J. Freedman and Jonathan D. Wallis 2002. “The Prefrontal Cortex: Categories, Concepts and Cognition.” In: Phil. Trans. R. Soc. Lond. B 357: 1123–1136

A Zombie’s Inquiry Into the Evolution of his Most Favorite Meal II

In my last post I listed some important factors in the evolution of the human brain, or better imagined what a zombie evolutionary biologist, named George, might dig up when investigating the evolutionary path of his Dinner Nr. 1. As Terrence Deacon (1997) puts it, there is no escaping the fact that human brains are unusually large. There are several factors why humans could develop large brains, but what is still at stake is the question why they actually did, and how they came into a position that allowed them to devote so much energy to a walnut-shaped pink lump of tissue with the consistency of a half-baked egg.
This question is critical, because organisms do not normally develop new traits just because they can. This of course also happens, in combination with random genetic drift and populations bottlenecks. But because evolution is a ‘miserable and greedy tinkerer’, or put more nicely, an economical process, it is highly unlikely that it produces needless and incredibly complex capacities that are extremely costly to maintain. As a consequence,

“some proportionately beneficial advantage must have driven brain evolution against the steep selection gradient created by the high costs of brain tissue.” (Dunbar & Shultz 2007)

Why, Dunbar and Shultz ask further, do primates have so much bigger brains than squirrel, with both facing about the same foraging decisions? (Dunbar & Shultz argue that ecological explanations fail to account for this differences, but their Chimpanzee-Squirrel dichotomy nevertheless is a bit hyperbolical, given that, among primates, those whose diet includes insects and fruits show higher encephalization rates than leaf-eaters, and strategic hunting and gathering of food and prey places additional demands on navigational, representational and other cognitive skills. However, their general argument is still valid. (Park et al. 2007))

To shed light on this issue, we can divide the big picture into several smaller ones. Useful questions include: What are we good at? Split into What are we (primates) good at? And What are we (humans) even better at than other primates? What could the ecological niche favoring big brains in humans have looked like? How exactly does our brain differ from that of other primates?
These questions essentially depend on comparative ethology (how do our minds work compared to how the minds of other animals work?), comparative (neuro)anatomy (On which evolutionary foundations are our modern cognitive abilities, and other phenotypic traits built upon?), and the kind of scenario we envision or infer from these observations togther with the fossil record and other lines of evidence. Of course it is also crucial what we think what the most salient and essentially aspects of our ancestors were. Do we see our ancestor as “Man the Tool Maker”, “Man the Hunter” or “Man the Social Animal”, or just as “Man with the extraordinarily big & expensive (and extremely delicious, George might add) brain”.

Well, of course Man should probably rather be seen as “Man the cooperative, competitive, tool-making, hunting, {…}, articulate social animal.” And all of these property probably contributed (co-evolutionary, we might say, without adding much in terms of explanatory adequacy) to our cognitive abilities and brain size, but in which order? And which driving forces were a little more pushy than others?
As Cheney & Seyfarth (2007) have show in baboons, interactions in primate groups are cognitively highly demanding and require sophisticated representational and predictive abilities, because of the intricate and complex networks and ‘friendships’ they inherit. Thus rising complexity in social life could be seen as a key selection pressure in the evolution of cognitive abilities in primates in general, and especially in humans. (Lewin 2005: 220f.)
Depending on which aspect one wants to stress, this correlations can be described in different terms. Scholars who wanted to stress the competitive aspect of social life dubbed it the “Machiavellian Intelligence Hypothesis.” (Byrne & Whiten 1988: who themselves, interestingly, didn’t want to stress the competitive aspect by giving the hypothesis the title). Now it is most widely called the “Social Brain Hypothesis” to emphasize the general complexity of primate groups including all arising affordances (Dunbar 1998, Dunbar & Shultz 2007).
Unfortunately, this is still rather vague. To get a clearer picture, it is important to make explicit the advantages and disadvantages of large social groups and the specific problems which need to be solved. However, group size indeed seem to contribute advantageously to genetic fitness by minimizing predation risk, but paired with greater ecological and reproductive competition and suppression, affording higher behavioral flexibility (Dunbar & Shultz 2007). Brain expansion theories stressing the importance of ’technological intelligence’ as a driving force. (without neglecting the importance of social factors, but seeing the latter as less crucial). According to these views, the ‘behavioral drive’ for cultural transmission and innovation is more frequent in species with large brains. As a consequence these species are led to exploit the environment in new way, opening up new possibilities regarding new selective pressures. ´(Reader and Laland 2002). Certainly, these tendencies were important, but where do they come from? Big-brains seem to be a prerequisite for ‘technological intelligence’, but how did these evolve in the first place? Rather it seems probable that

“Although innovation, tool use, and technological invention may have played a crucial role in the evolution of ape and human brains, these skills were probably built upon mental computations that had their origins and foundations in social interactions.” (Cheney & Seyfarth 2007: 283).

Supporting Reader and Laland’s emphasis on the importance of technological aspects on human cognitive evolution, Tomasello and his colleagues propose that human’s advanced Theory of Mind-skills were amplified not in the context of intention-reading present in great apes, but rather during learning and imitation of hierarchical planned and structured tool-making and tool-using. (Tomasello et al. 2005: 687). I’m not sure whether George would like this speculation. Probably, he would argue this to be a ‘just-so story’ and propose that all scientist coming up with these should be eaten. So thank God scientists are not really zombies, I wouldn’t miss the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany (and especially its co-director) for anything in the world (OK, except for the really important things such as love, life, family, donuts.

I haven’t addressed much of the questions stated in the beginning, especially What we as humans are especially better at than other primates. I will come to this issue in my next post (relying again on research done by scientists from the Max Planck Institute for Evolutionary Anthropology, so again, glad they haven’t been eaten.)

References:

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. Chicago: University of Chicago Press.

Deacon, Terrence William 1998. The Symbolic Species. The Co-evolution ofLanguage and the Brain. New York / London: W.W. Norton

Dunbar, Robin I.M.1998.“The Social Brain Hypothesis” Evolutionary Anthropology 6: 178-190.

Dunbar, R. I. M. and Susanne Shultz. 2007.“Evolution in the Social Brain” Science 317: 1344-1347

Park, Min S., Andrew D. Nguyen, Henry E. Aryan, Hoi Sang U, Michael L. Levy, Katerina Semendeferi. 2007. “Evolution of the Human Brain: Changing Brain Size and the Fossil Record.” Neurosurgery 60:555–562.

Reader, S.M. and K.N. Laland. 2002. “Social Intelligence, innovation, and enhanced brain size in primates” PNAS 99: 4436-4441

Tomasello, Michael, Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll. 2004. “Understanding and Sharing Intentions: The Origins of Cultural Cognition.” Behavioral and Brain Sciences 28

Zombies have Taste

In my last post I wrote about the fact that human brains are selfish energy-hungry little bastards, which makes the stuff they’re made of extremely ‘expensive tissue’ (Aiello & Wheeler 1995). This means that zombies have a quite extraordinary taste, equivalent to a caviar-gourmet (either that, or they are ‘informavores’ just like we are (Miller 1991)).
Now imagine (instead of the oft-cited martian scientist) a zombie-evolutionary biologist (Insert joke about the parasitic tendencies of the ‘mindless new atheism’ and/or Intelligent Design, the Idea of theistic evolution, greedy reductionism, Evolutionary Psychology or whatever floats you boat here) puzzling over the evolutionary emergence of his most favorite meal. Let’s take it for granted that our zombie-scientist is not easily satisfied by zombie-centric evolutionary concepts, just as Steven Pinker warns us that, if Elephants were the most culturally advanced species (well, and maybe they are, who knows), their evolutionary biologist (albeit only the bad ones) would probably search for the evolutionary path that inevitably climaxed in the highest form, the evolutionary optimum of trunkitude. Let’s also assume our zombie-scientist isn’t a friend of ‘just-so’ stories like ‘humans evolved bigger brains to run away from zombies more effectively’. Assuming, too, that human scientist like Aiello, Wheeler, Dunbar and others weren’t eaten before publishing their caveats about the expensiveness of brain evolution and maintenance, or that some other zombie-scientists could hold back their hunger long enough to test human subjects before eating them, coming to similar conclusions as Aiello and others did – or, rather would have come if they hadn’t been eaten beforehand. Assuming this, we could be sure that our zombie-scientist would not regard the evolution of a ‘general being-eaten-avoidance intelligence’ as unlikely.

What then, our zombie-scientist, call him George, would ask, was the reason humans developed such large, specialized brains. Looking for homologues or convergent evolution in other (hopefully not entirely eat… I mean extinct) species, and considering what makes the human mind special. George could come up with a lot of possible hypotheses as driving forces and triggers of brain evolution, and other facts he would have a hard time to make sense of such as:

• positively selected genes involved in regulating (Microcephalin: Evans et al. 2005) and determining brain size (ASPM: Mekel-Brobov et al. 2005), development of the human neocortex (HAR1F: Pollard et al. 2006), and playing a part in progressive changes in cognitive abilities (Neuropsin: Li et al. 2004)
  
• 
  
• cooking, paired with gastrointestinal shrinkage (our intestinal tract is only 60% the size expected of a primate with similar size) may have saved energy from digestion which in turn could be used to help fuel the brain. Together with the possible role of meat and more efficient upright walking and running, this could have expanded the human energy budget significantly (Gibbons 2007)
  
• 
  
• supporting this hypothesis, AMY1, a gene improving the digestion of food containing starch, is found in much greater numbers in humans than in chimpanzees (Perry et al. 2007)
  
• 
  
• Correlations between group size and neocortex size (Dunbar 1993, Dunbar & Shultz 2007) on the one hand, and significant positive correlation between innovation, social learning, tool use and brain size on the other, (Reader and Laland 2002, Reader 2003), making it likely that social and technological innovative intelligence (mediated by social learning) both played a crucial and inseparable role in human brain evolution (Cheney & Seyfarth 2007)
  
• 
  
• The possibility that the ability to evolve fat babies was the precursor for the evolution of the big and metabolically expensive brain (The article proposing this hypothesis is called ‘survival of the fattest’, What a great pun! Er… or maybe not) . In a resting newborn baby, the brain consumes 74% of the baby’s energy intake. In a 4-6 months old baby the rate is 64%, further dropping during ontogenetic development until reaching a rate of about 23% in adults. And whereas in chimpanzee infants, there is virtually no body fat, in human infants body fat contributes about 11-14% of the baby’s weight (as does the baby’s brain) (Cunnane & Crawford 2003)
  

So one thing is clear: a stable high-energy food supply was essentially necessary for human brain development, as were the possibility for longer ontogenetic development (as often observed, human (and generally primate) newborns are pretty much helpless compared to newborns of other species, with some even able to walk following almost immediately after birth).
Another important aspect is the general tendency in mammals to develop bigger brains compared to other species (they are about 10 times ‘brainier’ than amphibians or reptiles). Then, humans are part of the order of primates, which (along with toothed whales) have bigger brains than other mammals. And among primates, monkeys and apes have the biggest brains. But, as I said, our brains are even three times bigger than that expected of an ape of similar size. Another factor is the fact that the pre-natal rapid brain growth observed in other species whose infants are relatively helpless continues post-natally in human babies for about twelve months instead of changing into a slower pace.
As a consequence, human infants are even more helpless than that of other primates. This requires a much greater devotion of time, energy and other resources from the parent’s side. (Lewin 2005: 217f., John L. Locke and Barry Bogin (2005) make a similar argument concerning the unique human life history and ontogenetic development, but extending it not only to brain growth in general, but also to the evolution of language).
Making such a list, George would probably have a lot of trouble to distinguish preconditions, epiphenomena, co-evolutionary processes and driving forces of brain expansion. In my next post I will try to shed some light on this issue (Of course I will fail even more grotesquely than someone who is not a complete layman, but I hope that I will at least clarify some points)

References:

References:

Aiello L.C. and P. Wheeler 1995. ”The expensive tissue hypothesis: the brain and the digestive system in human and primate evolution.” Current Anthropology 36:199–221

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. Chicago: University of Chicago Press.

Cunnane Stephen C. and Michael A. Crawford. 2003. “Survival of the fattest: fat babies were the key to evolution.” Comparative Biochemistry and Physiology Part A: 136.1: 17-26

Dunbar, R.I.M. 1993. “Co-evolution of Neocortex size, group size and language in humans.” Behavioral and Brain Sciences 16.4: 681-735

Dunbar, R. I. M. and Susanne Shultz. 2007.“Evolution in the Social Brain” Science 317: 1344-1347

Evans, Patrick D., Sandra L. Gilbert, Nitzan Mekel-Bobrov, Eric J. Vallender, Jeffrey R. Anderson, Leila M. Vaez-Azizi, Sarah A. Tishkoff, Richard R. Hudson, Bruce T. Lahn “Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans” Science 309: 1717-1720.

Gibbons, Ann. 2007. “Food for Thought.” Science 316. 1558-1560.

Lewin, Roger. 2005. Human Evolution: An Illustrated Introduction. Fifth Edition. Suffolk: Blackwell.

Locke, John L. and Barry Bogin. 2005. “Language and life history: A new perspective on the development and evolution of human language” Behavioral and Brain Sciences

Mekel-Bobrov, Nitzan, Sandra L. Gilbert, Patrick D. Evans, Eric J. Vallender, Jeffrey R. Anderson, Richard R. Hudson, Sarah A. Tishkoff, Bruce T. Lahn. “Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens.” Science 309: 1720-1722

Li, Yi, Ya-ping Qian, Xiao-jing Yu,* Yin-qiu Wang, Ding-gui Dong’ Wei Sun, Run-mei Ma and Bing Su. 2004. “Recent Origin of a Hominoid-Specific Splice Form of Neuropsin, a Gene Involved in Learning and Memory.“ Molecular Biology and Evolution 21.11: 2111-2115.

Miller, G.A. 1991. The Science of Words. New York: W.H. Freeman

Reader, S.M. 2003. “Relative brain size and the distribution of innovation and social learning across the nonhuman primates.” The Biology of Traditions: Models and Evidence. Eds. D.M. Fragaszy and S. Perry, 56-93.

Reader, S.M. and K.N. Laland. 2002. “Social Intelligence, innovation, and enhanced brain size in primates” PNAS 99: 4436-4441.

Pollard, Katherine S., Sofie R. Salama, Nelle Lambert, Marie-Alexandra Lambot4, Sandra Coppens, Jakob S. Pedersen, Sol Katzman, Bryan King, Courtney Onodera, Adam Siepel, Andrew D. Kern, Colette Dehay, Haller Igel, Manuel Ares Jr, Pierre Vanderhaeghen & David Haussler. 2006 “An RNA gene expressed during cortical development evolved rapidly in humans.” Nature 443: 167-172.

Perry, George H, Nathaniel J Dominy, Katrina G Claw, Arthur S Lee, Heike Fiegler, Richard Redon, John Werner, Fernando A Villanea, Joanna L Mountain, Rajeev Misra, Nigel P Carter, Charles Lee, & Anne C Stone. 2007 “Diet and the evolution of human amylase gene copy number variation“ Nature Genetics Advanced Online Publication doi :10.1038/ng2123

Brains are Expensive

A while back, Larry Moran over at the Sandwalk wrote about previous expectations of scientist about the number of genes in the human genome. (See also his discussion of Pennisi 2005) The guesses ranged from 140,000 to 15,000 genes. Reading this I was reminded of a statement from Thompson (2001) which I quoted in a term paper about language evolution: 30,000 to 50,000 genes of the human DNA are present in all cells, but only activated in brain cells. This would be a quite extraordinary feat, given that there seem to be only about 20,488 genes at all in the human genome. (Pennisi 2007). But there are other statements that characterize the ‘hyperastronomical’ dimensions (Quine 1987) of the brain quite well. (Quine used the word when describing the vastness of Borges’ fictional Library of Babel, a universe-sized library which contains books with all possible combinations of characters there are, making it impossible to find even one comprehensible sentence. But as a complete layman, I sure sometimes feel the same when reading an article about neuroscience… or anything else for that matter)

The Brain consists of an incredible 10¹⁰ neurons and 10¹³ synapses (Gegenfurtner 2005) and the number of possible connectional combinations between is sometimes estimated to be greater than the number of molecules in the universe (Ramachandran) no wonder it is sometimes called the most complex structure in the know universe. Further, with its about 1251.8 cubic centimeters (cc) (compared to the 316.7 cc of greater apes) (Rilling 2006),our brain is about three times bigger than that of an ape would be, given the same body-size (Lewin 2005).
Just as remarkable is the amount of energy the brain consumes. Although the human brain weighs only 2% of an adult’s body weight, it accounts for 20-25% of its resting energy intake. As a comparison, a chimpanzee’s brain only consumes about 8-9% of its resting metabolism. Thus, the brain uses energy at the same rate consumed by leg muscles of a marathon runner when running (Attwell & Laughlin 2001. It seems like that one could make a good joke out of this fact, but sadly I can’t really imagine how.) The costs to run a human brain are, per unit mass, about 8 to 10 times higher than those for skeletal muscles. In the energy-consuming business, it is only topped by the heart. (Dunbar & Shultz 2007).

At the moment there doesn’t seem to be enough data to estimate which brain areas consume how much energy, but there are two promising candidates for the title of ‘hungriest brain area’. 50% to 60% of the human cerebral cortex are devoted to the perception and interpretation of visual stimuli and the reactions to it. Given that, perception is an incredibly complicated and complex task, this seems quite understandable: In sum, the brain receives about two gigabyte of data per second from approximately 200 million photo receptors in the eyes (Gegenfurtner 2005). Another aspirant for the title are the auditory areas, where metabolic rates seem to be 40% greater than in other parts of the brain (Attwell & Laughlin 2001).
Brains really are made out of “expensive tissue” (Aiello & Wheeler 1995). Because of this, specialized intelligence is far more likely to be created by natural selection than general intelligence, or a brain that is ‘just large’ due to the sheer cost of evolving and maintaining such a thing. (Cheney & Seyfarth 2007: 11) (Ha! Suck on this Jean Piaget! ;) ) As Robin Dunbar puts it: “Because the cost of maintaining a large brain is so great, it is intrinsically unlikely that large brains will evolve merely because they can. Large brains will evolve only when the selection factor in their favor is sufficient to overcome the steep cost gradient“ (Dunbar 1998: 179). In my next post I will consider some of the proposals why we do have such damn hungry and huge brains.

References:

Aiello L.C. and P. Wheeler 1995. ”The expensive tissue hypothesis: the brain and the digestive system in human and primate evolution.” Current Anthropology 36:199–221

Attwell, David and Simon B. Laughlin. 2001. “An Energy Budget for Signaling in the Grey Matter of the Brain.” Journal of Cerebral Blood Flow and Metabolism 21:1133–1145.

Dunbar, Robin I.M.1998.“The Social Brain Hypothesis” Evolutionary Anthropology 6: 178-190.

Dunbar, R.I.M. and Susanne Shultz. 2007. .“Evolution in the Social Brain” Science 317: 1344-1347

Lewin, Roger. 2005. Human Evolution: An Illustrated Introduction. Fifth Edition. Suffolk: Blackwell.

Quine, W. V. 1987. Quiddities: An Intermittently Philosophical Dictionary. Cambridge, MA: Belknap Press

Pennisis, Elizabeth. 2005. "Why do Humans have so Few Genes?" Science 309: 80.

Pennisis, Elizabeth. 2007. "Working the (Gene Count) Numbers: Finally, a Firm Answer?" Science 316: 1113.

Rilling, James K. 2006. Human and NonHuman Primate Brains: Are They Allometrically Scaled Versions of the Same Design? Evolutionary Anthropology 15: 67-77.

Thompson, Richard F. 2000. The Brain: A Neuroscience Primer. Third Edition. New York: Worth Publishers.

Evolutionary Metaphysics V

So this is my last post about “Baboon Metaphysics” and what we get if we try to combine it with some other lines of research. Now which steps were necessary for the evolution of the human mind and language, and in which order?
As a starter, our LCAs with chimpanzees should have exhibited or later evolved the following traits:

1 A rudimentary Theory-of-Mind and a conceptual system which enabled them to form multimodal mental-representations had to be present (Cheney & Seyfarth 2007, Barsalou 2005, Gil-da-Costa et al. 2004)

2a enhanced displaced conceptual control somehow evolved, probably due to prefrontal enlargement, resulting in higher frontal control over neural processes (Barsalou 2005, Deacon 1998, Miller et al. 2002, Rilling 2006)

2b enhanced ToM-abilities, probably influenced by greater frontal control, but also due to some elaboration of an existing mirror neuron system (which is present, for example in maqaques) which then was integrated into a higher order system together with cortical midline structures responsible for social and self-evaluation and possibly other information structures, forming the ‘social network.’ (Cheney & Seyfarth 2007, Uddin et al. 2007, Wheatley et al. 2007, Barsalou in press a, Rizzolatti & Craighero 2004)

3. Greater social and cultural complexity paired with the motivation to cooperate and share mental states with others (Tomasello et al. 2005, Herrmann et al. 2007), possibly co evolutionary influences of social complexity, theory of mind (Dunbar 1998, Dunbar & Shultz 2007) as well as technological advances (Reader and Laland 2002, Reader 2003) and brain expansion.

4. higher ability of displaced, goal-directed an planning simulation of physical categories (physical stance, folk physics) functional categories (design stance, folk biology, mechanics) and intentional categories (intentional stance, folk psychology, ToM) aiding survival and reproductive success trough comprehensive prediction in dangerous environments and socially complex groups (Dennett 1987, Poirier et al. 2005, Tooby & DeVore 1987, Ryder & Favorov 2001)

5. Evolution of extensive symbolic capacities and ‘protolanguage’(which I haven’t addressed here) aided among other factors by displaced frontal control and other selective pressures such as the need to communicate displaced information, share intentions and cooperate, foraging, competition, sexual selection such as display of genetic fitness, establishment of trust, etc. etc. (Deacon 1998, Bickerton 2006, Jackendoff 2002, Pinker 1994, Tomasello et al. 2005, Desalles 2007, Franks and Rigby 2002).

6. Further enhancement of symbol-usage through interactions between language and embodied simulation and ‘symbolic theft’ (embodied-experience to language mapping) (Barsalou in press b, Cangelosi et al. 2002)

7. Evolutionary/cultural feedbacks from language to the conceptual system (Lupyan 2006, Burling 2005, Barsalou 2005, in press a) and further influence of metaphorical structure to language (Lakoff and Johnson, 1987, 1999). The ability to blend mental spaces together and form what-if structures and envision technological/cultural innovations, and goal-directed actions (Turner 2003, Miller et al. 2002,Cheney and Seyfarth 2007) Cheney & Seyfarth write that if you search for what-if on Google you’ll get about 150,000,000 hits, which as they say, might be too much of a good thing.

Oh yeah, and mirror neurons also possibly played a rule in language evolution (Arbib 2005). And I didn’t say anything about syntactic/grammatical evolution (Jackendoff 2002) And I forgot recursion (Hauser et al. 2002) as well. And as almost everyone else I’m sure the Baldwin Effect has something important to do with language evolution (Jackendoff 2002, Kirby 2000). Neither did I address the fact that… oh well, as you see, language evolution is a pretty darn complex interdisciplinary field, but I think I pinpointed some of the (if not all) key issues critical for the evolution of language and the human mind. Hope you enjoyed my digressions inspired by Cheney and Seyfarth’s book. Cheers.

References:

Arbib, Michael A. 2005. “From monkey-like action recognition to human language: An evolutionary framework for neurolinguistics.” Behavioral and Brain Sciences 28: 105-167

Barsalou, Lawrence W. 2005. “Continuity of the conceptual system across species.” Trends. Cog. Sc. 9.7: 309-311.

Barsalou, Lawrence W. In press. “Grounded Cognition.” In: Annual Review of Psychology 59

Barsalou, Lawrence W. in press b. “Grounding symbolic operations in the brain’s modal systems.” Embodied grounding: Social, cognitive, affective, and neuroscientific approaches. Eds. G.R. Semin & E.R. Smith. New York: Cambridge University Press.

Bickerton, Derek. 2006. “Language Evolution”

Burling, Robbins. 2005. The Talking Ape. Oxford: OUP

Cangelosi, A., Greco, A., & Harnad, S. 2002. “Symbol Grounding and the Symbolic Theft Hypothesis”. Simulating the Evolution of Language. Eds. A.Cangelosi & D. Parisi . London: Springer

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. Chicago: University of Chicago Press.

Deacon, Terrence William 1998. The Symbolic Species: The Co-evolution of Language and the Brain. New York / London: W.W. Norton.

Dennett, Daniel C. 1987. The Intentional Stance. Cambridge, M.A.: Bradford Books.

Desalles, Jean-Louis. 2007. Why We Talk. Oxford: OUP.

Dunbar, Robin 1998. “Theory of Mind and the Evolution of Language.” In: James
R. Hurford, Michael Studdert-Kennedy and Chris Knight (eds.). Approaches to the Evolution of Language. Social and Cognitive Bases. Cambridge: Cambridge University Press

Dunbar, R. I. M. and Susanne Shultz. 2007.“Evolution in the Social Brain” Science 317: 1344-1347

Franks, Bradley and Kate Rigby 2005. “Deception and mate selection: some implications for relevance and the evolution of language” Language Origins: Perspectives on Evolution. Ed. Maggie Tallerman. Oxford: OUP.

Gil-da-Costa, Ricardo, Allen Braun, Marco Lopes, Marc D. Hauser, Richard E. Carson, Peter Herscovitch and Alex Martin. 2004. “Toward an evolutionary perspective on conceptual representation: Species-specific calls activate visual and affective processing systems in the macaque.” PNAS 101.50: 17516–17521.

Hauser, Marc D., Noam Chomsky and W. Tecumseh Fitch 2002. “The Faculty ofLanguage: What Is It, Who Has It, and How Did It Evolve?” In: Science 298, 1569-1579.

Herrmann, Esther, Josep Call, María Victoria Hernández-Lloreda, Brian Hare, and Michael Tomasello. 2007. “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis.” Science 317: 1360-1365.

Jackendoff, Ray. 2002.. Foundations of language: brain, meaning, grammar, evolution. Oxford: Oxford University Press.

Kirby, Simon 1998. “Fitness and the Selective Adaptation of Language.” In: James R. Hurford, Michael Studdert-Kennedy and Chris Knight (eds.). Approaches to the Evolution of Language. Social and Cognitive Bases. Cambridge: Cambridge University Press, 359-383.

Lakoff, George, and Mark Johnson 1980. Metaphors we live by. Chicago: University of Chicago Press.

Lakoff, George and Mark Johnson. 1999. Philosophy in the Flesh: The Embodied Mind and its Challenge to Western Thought. New York: Basic Book

Lupyan, Gary. 2006. “Labels Facilitate Learning of Novel Categories.” The Evolution of Language: Proceedings of the 6th International Conference. Eds. A. Cangelosi, A.D.M. Smith & K.R. Smith Singapore: World Scientific,190-197

Miller, Earl K., David J. Freedman and Jonathan D. Wallis 2002. “The Prefrontal Cortex: Categories, Concepts and Cognition.” In: Phil. Trans. R. Soc. Lond. B 357: 1123–1136

Poirier, Pierre, Benoit Hardy-Vallée and Jean-Frédéric Depasquale.2005. “Embodied Categorization.” Handbook of Categorization in Cognitive Science. Eds. Henri Cohen and Claire Lefebvre. Amsterdam: Elsevier, 2005.

Pinker, Steven 1994. The Language Instinct: The New Science of Language and Mind. London: Lane Penguin Press.

Reader, S.M. 2003. “Relative brain size and the distribution of innovation and social learning across the nonhuman primates.” The Biology of Traditions: Models and Evidence. Eds. D.M. Fragaszy and S. Perry, 56-93.

Reader, S.M. and K.N. Laland. 2002. “Social Intelligence, innovation, and enhanced brain size in primates” PNAS 99: 4436-4441.

Rilling, James K. 2006. Human and NonHuman Primate Brains: Are They Allometrically Scaled Versions of the Same Design? Evolutionary Anthropology 15: 67-77.

Ryder, Dan and Oleg V. Favorov. 2001. “The New Associationism: A Neural Explanation for the Predictive Powers of Cerebral Cortex.” Brain and Mind 2.2. 161-194.

Tomasello, Michael, Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll. 2004. “Understanding and Sharing Intentions: The Origins of Cultural Cognition.” Behavioral and Brain Sciences 28.4

Tooby, John and Irven DeVore 1987. “The Reconstruction of Hominid Rvolution Through Strategic Modelling.” The Evolution of Human Behavior: Primate Models. Ed. W.G. Kinzey. Albany: SUNY.

Turner, Mark. 2003. “Double-Scope Stories.” Narrative Theory and the Cognitive Sciences. Ed. David Herman

Rizzolatti, Giacomo and Laila Craighero. “The Mirror-Neuron System.” Annual Review of Neuroscience 27 (2004): 169–192.

Uddin, Lucina Q., Marco Iacoboni, Claudia Lange and Julian Paul Keenan. 2007.“The Self and Social Cognition: The Role of Cortical Midline Structures and Mirror Neurons.” Trends in Cognitive Sciences 11.4 53-157.

Wheatley, Thalia, Shawn C. Milleville and Alex Martin. “Understanding Animate Agents: Distinct Roles for the Social Network and Mirror System.” Psychological Science 18.6 (2007): 469-474.

Evolutionary Metaphysics IV

Since I drifted away from discussing baboons and Cheney and Seyfarth’s book quite a bit, I decided to name this post (jokingly) ‘Evolutionary Metaphysics, because, according to the OED, metaphysics includes questions about

"the underlying concepts or first principles on which a particular branch of knowledge is based."

OK, there actually is already such a field, called evolutionary epistemology, or its evil twin brother, evolutionary psychology, but I’ll still go with this title.
In my last post, I considered some proposals how our – in some parts species-continuous – conceptual system had been extended. Deacon (1998) and Barsalou (2005) both observed the higher frontal cortical control which humans show compared to other animals. Whereas Deacon proposed that we had a ‘front heavy’ cognitive style, Barsalou broke our conceptual extensions down into component parts. Some of them explicitly seem to be reliant on frontal control, such as Mental Time Travel and Conceptual Blending.
Another proposal for a human specialization similar to these traits is cause-and-effect reasoning, in order to outwit defences of plants and animals, as well as competitors (Tooby and DeVore 1987). The enhancement of these capacities in humans is congruent with the fact that the prefrontal cortex synthesizes the information received from other areas into representations of concepts, rules and contingencies, and that this structure is especially elaborate in primates and especially so in humans (Miller et al. 2002, Deacon 1998, Ivry & Knight 2002). Prefrontal enlargement could have led to enhanced cognitive control over the conceptual system, and thereby to a greater cognitive control over our own actions and their goals.

However, when taking into account human ToM-abilities, there seems to be a lot more to it than just prefrontal enlargement. How wan we take different perspectives and attribute false beliefs to others? Regarding the blending of incompatible concepts, Mark Turner asks: ”How can we fire up incompatible mental patterns simultaneuously […] Evolutionary, how did our species develop this ability?” (Turner 2003: 118). What are the evolutionary steps complementing higher frontal control?
Cheney and Seyfarth amassed evidence for the existence of mental representations in baboons; neuroimaging studies showed the same for macaque monkeys (Gil-da-Cost et al. 2004). Following Barsalou (2005) in assuming a common architecture for human and animal conceptual systems, what are the foundations of social cognition in other animals, on which human ToM-abilities were built?
One part of the answer seems to lie in the discovery of ‘mirror neurons’ “a particular class of visuomotor neurons, originally discovered in area F5 of the monkey premotor cortex, that discharge both when the monkey does a particular action and when it observes another individual (monkey or human) doing a similar action” (Rizzolatti et al. 2001: 661). A similar mirror neuron system crucial to the understanding of action, imitation, and also involved in language is argued to exist in humans (Rizzolatti/Craighero 2004). Mirror neurons sometimes seem to be hyped as the answer to every open question in the cognitive studies, but at the moment no one really seems to know what to conclude from them.

So how do we understand others? Gallese and his colleagues (2004) propose that we understand others and infer mental states to them by simulating their actions in our ‘mirror system.’ These proposals are in accordance with Barsalou’s view of conceptualization as integrated simulations of experience-based concepts in our conceptual system (Barsalou in press) But as Barsalou himself stresses, mirror circuits seem to be part of a larger system which also involves inhibitory processes that keep simulated and own mental states apart from each other (Decety and Grazes 2006) and the establishment of joint attention (Sebanz et al. 2006).
This larger system is sometimes identified as a functional system called ‘social network’ which integrates contributed information from others systems into the mental representation of an animate being (Wheatley et al. 2007). Wheatley and colleagues found that the mirror system does not respond selectively to biological actions, but to actions in general. The failure of the mirror system to be modulated by the interpretation of animacy when observing or simulating an action makes it unlikely to be the origin of general social cognition. Instead, Wheatley and his colleagues argue that inferring animacy is done by the ‘social network’ and propose to see the mirror system as a general simulation machinery which is employed in tandem by the social network, imagery and other cognitive processes.They conclude that the social network’s ability to infer animacy should be seen as an important component of, as well as an evolutionary precursor to our complex social cognition and Theory of Mind-abilities.

Yet another component of the social network may be the so-called cortical midline structures (CMS), which process information about others and the self in more evaluative and abstract and ways (Uddin et al. 2007). Uddin and her colleagues see CMS and the mirror system as interactive components. They propose that the mirror system is responsible for the ability to map representations of others onto our own mental architecture, and that the CMS evaluates and underscores these mappings. It would be interesting to know if CMS exist in non-human primates and other animals, and if not, if there are possible homologues. Another question is if Wheatley et al.’s and Uddin et al’s proposals are compatible. I, for instance, have no idea. In my next post I will sum up my previous observations and see if I can draw some rough skeletal evolutionary scenario from it.

References:

Barsalou, Lawrence W. In press. “Grounded Cognition.” In: Annual Review of Psychology 59

Barsalou, Lawrence W. 2005a. “Continuity of the conceptual system across species.” Trends. Cog. Sc. 9.7: 309-311.

Deacon, Terrence William 1998. The Symbolic Species: The Co-evolution ofLanguage and the Brain. New York / London: W.W. Norton.

Decety, Jean, & Julie Grèzes. 2006. “The power of simulation: Imagining one's own and other's behavior.” Brain Research 1079: 4-14.

Gil-da-Costa, Ricardo, Allen Braun, Marco Lopes, Marc D. Hauser, Richard E. Carson, Peter Herscovitch and Alex Martin. 2004. “Toward an evolutionary perspective on conceptual representation: Species-specific calls activate visual and affective processing systems in the macaque.” PNAS 101.50: 17516–17521.

Ivry Richard and Robert T. Knight. 2002. “Making order from chaos: the misguided frontal lobe” Nature Neuroscience 5.5: 394-396.

Miller, Earl K., David J. Freedman and Jonathan D. Wallis 2002. “The Prefrontal Cortex: Categories, Concepts and Cognition.” In: Phil. Trans. R. Soc. Lond. B 357: 1123–1136

Rizzolatti, Giacomo and Laila Craighero. “The Mirror-Neuron System.” Annual Review of Neuroscience 27 (2004): 169–192.

Rizzolatti, Giacomo, Leonardo Fogassi and Vittorio Gallese. “Neurophysiological Mechanisms Underlying the Understanding and Imitation of Action.” Nature Reviews Neuroscience 2 (2001): 661–670.

Sebanz, N., Bekkering, H., & Knoblich, G. 2006. Joint action: Bodies and minds moving together. Tr. Cog. Sc. 10: 70-76.

Tooby, John and Irven DeVore 1987. “The Reconstruction of Hominid Rvolution Through Strategic Modelling.” The Evolution of Human Behavior: Primate Models. Ed. W.G. Kinzey. Albany: SUNY.

Uddin, Lucina Q., Marco Iacoboni, Claudia Lange and Julian Paul Keenan. 2007. “The Self and Social Cognition: The Role of Cortical Midline Structures and Mirror Neurons.” Trends in Cognitive Sciences 11.4 (2007): 153-157.

Wheatley, Thalia, Shawn C. Milleville and Alex Martin. “Understanding Animate
Agents: Distinct Roles for the Social Network and Mirror System.” Psychological Science 18.6 (2007): 469-474.

Baboon Metaphysics III: Links with other Fields of Cognitive Science

In my last post I argued that “Baboon Metaphysics” only mentioned half of the story of what makes the human conceptual system unique. What Cheney and Seyfarth did not address in their still absolutely excellent and insightful book, is the way our conceptual system has been extended in respect to that of other animals, and the way language may interact with conceptualization and other cognitive processes, instead of simply being the expression of cognitive processes absolutely independent from it. (Although I don’t want to attribute such a view to Cheney and Seyfarth just because they haven’t said anything about it, this theory still seems to be quite prominent. See, for example, Edmund Blair Bolles' review of Steven Pinker’s new book “The Stuff of thought (2007) ).
In the words of Robbins Burlings (2005): “What has language done to us?” Work by Gary Lupyan and others shows that there is evidence that language, thinking, and concepts interact and that language helps us organize and categorize the world and sometimes alters how we process information (Kenneally 2007: 106-111). This is certainly not a return to strong versions of the Sapir-Whorf thesis, considering that Cheney and Seyfarth clearly showed that there are concepts and conceptualization without language, and evidence that language itself is partly grounded in embodied cognition (Lakoff and Johnson 1980, Lakoff and Johnson 1999). But these interactive processes, and the way our own extended conceptual abilities rely on enhanced cognitive supplements to our basic neural architecture, are definitely part of the whole picture.

In my last post, I mentioned that Barsalou (2005) argued that frontal lobe control is a critical factor enhancing the displacement- and computation-abilities of conceptual simulation, and therefore a crucial factor of defining what makes the human extended conceptual system different from animal mental representations, which evolutionary are the basic architecture for our cognitive abilities, and which Cheney and Seyfarth described marvelously. Terrence Deacon has a similar proposal what makes us human. According to him

“The prominent enlargement of the prefrontal cortex and the correlated shifts in connection patterns that occurred during human brain evolution introduced strong biases into the learning process and gave human prefrontal circuits a greater role in many neural processes unrelated to language. Though intense selection was directed toward this one aspect of mind and brain, its secondary effects have also ramified to influence the whole of human cognition. (Deacon 1998: 417)

Because the prefrontal cortex is the most important structure that supports symbolic reference (Deacon 1998: 266) and in human beings, prefrontal circuits play a greater role in all neural processes of the brain than in any other species (Deacon 1998: 265), we are “The Symbolic Species” inhabiting mental worlds mediated by thousands of hierarchical structured symbol-symbol relationships (see also Kenneally’s (2007) prelude for a quite poetic description of the semiotic universes we create and communicate about) intertwined with our physical lives, our embodied experience of the outside world. As I mentioned in my last post Barsalou (2005), too, sees our symbolic capacities mediated by greater frontal control as crucial:

“What results is control of the distributed property architecture to represent components of situations and to combine them in novel ways.“

These combination of representations into an ‘integrated simulation’, can be found in another field of inquiry, namely mental images:

“Mental images need not result simply from the recall of previously perceived objects or events; they can also be created by combining and modifying stored perceptual information in novel ways.” (Kosslyn et al. 2001).

Interestingly “most of the neural processes that underlie like-modality perception are also used in imagery; and imagery, in many ways, can ‘stand in’ for (re-present, if you will) a perceptual stimulus or situation“ (Kosslyn et al. 2001). This supports Barsalou’s view that conceptualization consists of integrated “reenactments of perceptual, motor, and introspective states acquired during experience with the world, body, and mind “ (Barsalou in press). Also interesting in this regard is Mark Turner’s stance at what makes us uniquely human: conceptual blending - the integration of two mental spaces/conceptual structures to form a new one, enabling mental time travel and escape, as well as what-if relations. Turners describes it as “a basic human mental operation, with constitutive and governing principles. It played a crucial role, probable the crucial role, in the descent of our species over the last fifty or one hundred thousand years” (Turner 2003).

By the way, Edmund Blair Bolles has posted a great discussion of a paper by Don Ross which deals with the evolution of human culture and joint attention. Go check it out!

References:
Barsalou, Lawrence W. 2005a. “Continuity of the conceptual system across species.”
Trends. Cog. Sc. 9.7: 309-311.

Barsalou, Lawrence W. In press. “Grounded Cognition.” In: Annual Review of Psychology 59

Burling, Robbins. 2005. The Talking Ape. Oxford: OUP.

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. University of Chicago Press, Chicago

Deacon, Terrence William 1998. The Symbolic Species. The Co-evolution of
Language and the Brain. New York / London: W.W. Norton.

Pinker, Steven 2007. The Stuff of Thought: Language as a Window into Human Nature. New York: Viking.

Kenneally, Christine. 2007. The First Word: The Search for the Origins of Language. New York: Viking.

Kosslyn, Stephen M., Giorgio Ganis and William L. Thompson. 2001.“Neural Foundations of Imagery.” Nature Reviews Neuroscience 2: 635-642.

Lakoff, George, and Mark Johnson 1980. Metaphors we live by. Chicago: University of Chicago Press.

Lakoff, George and Mark Johnson. 1999. Philosophy in the Flesh: The Embodied Mind and its Challenge to Western Thought. New York: Basic Book

Turner, Mark. 2003. “Double-Scope Stories.” Narrative Theory and the Cognitive Sciences. Ed. David Herman

Baboon Metaphysics II

In my last post, I wrote about Dorothy Cheney’s and Robert Seyfarth’s new book “Baboon Metaphysics” and their claim that

“Baboons teach us that it is possible to have a complex society based on cognitive processes that are both computational and representational without either language or a theory of mind. Concepts (of a sort) can exist without words; computation can occur without grammar, Along with many other species of animals, baboons provide us with a natural experiment that allows us to ask “What it thought – what can it possibly be – without language and a theory of mind.?” (p. 276)

In their book, the authors refer to a wealth of other literature about animal communication, cognition and human evolution, and I will write about some of these papers from then to then.

One important implication of Cheney and Seyfarth’s argument is the “Continuity of the conceptual system across species“ (Barsalou 2005a), which outright contradicts the strong versions of the Sapir-Whorf-thesis, radical constructivism and cultural relativism. The Conceptual system is a “system distributed throughout the brain that represents knowledge about the world“(Barsalou 2005b: 621). Primates and monkeys have rich conceptual systems, they therefore can think without language. Conceptual representation in humans and monkeys has common neural substrates, suggesting how human cognition build upon these evolutionary precursors (Gil-da-Costa 2004).
Additional systems seem to have extended the conceptual abilities of humans significantly (Barsalou 2005a). And this is where, Cheney and Seyfarth’s “First thought, then language” ceases to tell the whole story. I don’t think this can really be called a shortcoming of the book, but I’m a bit disappointed that the authors didn’t at least hint at what makes our conceptual system different from that of other animals, and in which ways it could be influence by language. Though they stress that the human ability to have a theory of mind “favored an ability to speak, expand one’s vocabulary, and combine words in sentences to convey novel meanings” (p.281) and they concur with Tomasello et al. (2005) that “shared intentionality”, the motivation to cooperate with others and to share intentions and mental states with them, is a crucial principle of humanness, culture, and language, they still don’t go further than “Thought came first; speech and language appeared later, as its expression”(p.281).
But for me, the story doesn’t end here. Cheney and Seyfarth stress the fact that the “same basic architecture for representing knowledge is present in humans” (Barsalou 2005a), and rightly so. As Barsalou (2005b) puts it, conceptualization processes work

"via integrated simulations of agents, objects, settings, actions, and introspections. On recognizing a familiar type of category instance, an entrenched situated conceptualization associated with it becomes active to provide relevant inferences via pattern completion". (Barsalou 2005b: 645)

This pattern completion seems to be an essential feature of all cognitive systems, because it allows an organism to prepare for and predict actions and events, thus aiding survival. (Barsalou 2005). Many neuroscientists are convinced that the brain’s main task is prediction in order to survive in dangerous environments (Ryder/Favorov 2001), and, we can add with Cheney and Seyfarth, to be able to function in large social groups. With a theory of mind, humans have much better predictive strategies at hand, and thus are even better equipped to cooperate and function in large societies. This is one of the key themes in “Baboon Metaphysics.” But what else makes our conceptual system different, and how so? Besides having a ToM, Barsalou (2005a) argues that another uniquely human complement of the conceptual system is that they “represent situations that are completely unrelated to the current situation,” enhancing learning and future performance by mentally simulating past events, an maximizing the achievement of goals by simulation of planned events in the future.

Barsalou stresses the importance of the frontal lobe for such activations. He adds language as another possibility for the extensions of the human conceptual system. Barsalou speculates that “the linguistic system provides exquisite control over the simulation system as it represents non-present situations.” Thus, what could make humans essentially different, along with higher social ToM-competence, may be their “control of the distributed property architecture to represent components of situations and to combine them in novel ways.“ This ability again is hugely reliant on frontal activation. These observations resonate with Terrence Deacon’s (1998) depiction of our ‘front-heavy” cognitive style, which makes us “The Symbolic Species”, Mark Turner’s theory of Conceptual Blending, as well as with work by Stephen Kosslyn, which I will address in my next post on the book.
In sum, this combinations of Cheney and Seyfarth’s work with Barsalou’s and others considerations about the human conceptual system is, I think, extremely interesting, and makes “Baboon Metaphysics” – coming from one side and looking to meet with research such as Barsalou’s, Deacon’s, and Turner’s – an important milestone in our quest of unravelling the human mind.

References:
Barsalou, Lawrence W. 2005a. “Continuity of the conceptual system across species.” Trends. Cog. Sc. 9.7: 309-311.

Barsalou, Lawrence W. 2005b “Situated Conceptualization.” Handbook of Categorization in Cognitive Science. Eds. Henri Cohen and Claire Lefebvre. Amsterdam: Elsevier. 619-650.

Cheney, Dorothy L. and Robert M. Seyfarth. 2007. Baboon Metaphysics: The Evolution of a Social Mind. Chicago: University of Chicago Press.

Deacon, Terrence William. 1998. The Symbolic Species: The Co-evolution of Language and the Brain. New York / London: W.W. Norton.

Gil-da-Costa, Ricardo, Allen Braun, Marco Lopes, Marc D. Hauser, Richard E. Carson, Peter Herscovitch and Alex Martin. 2004. “Toward an evolutionary perspective on conceptual representation: Species-specific calls activate visual and affective processing systems in the macaque.” PNAS 101.50: 17516–17521.

Ryder, Dan and Oleg V. Favorov. 2001. "The New Associationism: A Neural Explanation for the Predictive Powers of Cerebral Cortex.” Brain and Mind 2.2. : 161-194.

Tomasello, Michael, Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll. 2004. “Understanding and Sharing Intentions: The Origins of Cultural Cognition.” Behavioral and Brain Sciences 28.5