Monday, May 19, 2008

Darwin's Mistake and Darwin's Triumph

After Chris of Mixing Memory and Deric Bownds of Deric Bownds' Mindblog had already drawn attention to the prefinal version of this article, “Darwin’s mistake: Explaining the discontinuity between human and nonhuman minds” by Derek Penn, Keith Holyoak and Daniel Povinelli has now finally been published in the current issue of the Behavioral and Brain Sciences.

Penn, who’s affiliated with the Cognitive Evolution Group at the University of Louisiana, and the University of California, Los Angeles, Holyoak, Professor of Psychology at the University of California, and Povinelli, Professor of Biology at the University of Louisiana, and also a member of the Cognitive Evolution Group, argue that

“Over the last quarter century, the dominant tendency in comparative cognitive psychology has been to emphasize the similarities between human and nonhuman minds and to downplay the differences as “one of degree and not of kind” (Darwin 1871). In the present target article, we argue that Darwin was mistaken: the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds. To wit, there is a significant discontinuity in the degree to which human and nonhuman animals are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system (PSS) (Newell 1980). We show that this symbolic-relational discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture alone can explain. We propose a representational-level specification as to where human and nonhuman animals’ abilities to approximate a PSS are similar and where they differ. We conclude by suggesting that recent symbolic-connectionist models of cognition shed new light on the mechanisms that underlie the gap between human and nonhuman minds.”

As was to expected the article sparked quite a lot of heated responses in the comment section both for it’s title and for its discontinuist view of human cognitive which emphasizes the large gulf that lies between human and nonhuman cognition. Those who are afraid that again a creationist/ID paper has made it into a respectable science journal, can calm down. In their first footnote Penn et al. make clear that:

"All similarities and differences in biology are ultimately a matter of degree. Any apparent discontinuities between living species belie the underlying continuity of the evolutionary process and largely result from the fact that many, and often all, of the intermediate steps are no longer extant. In the present article, our claim that there is a “discontinuity” between human and nonhuman cognition is based on our claim that there is a significant gap between the functional capabilities of the human mind and those of all other extant species on the planet. Our point, to cut to the chase, is that the functional discontinuity between human and nonhuman minds is at least as great as the much more widely acknowledged discontinuity between human and nonhuman forms of communication. But we do not doubt that both evolved through standard evolutionary mechanisms. (Penn et al. 2008: 129)

Interestingly, when you google “Darwin’s mistake” your fist hit is an amazon link for a book called “Darwin's Mistake: Antediluvian Discoveries Prove Dinosaurs and Humans Co-Existed” to which I won’t link because I don’t want to raise the page rank of such junk. The second link is a funny little poem called "Darwin's mistake", which goes like this:

“Three monkeys sat on a coconut tree

Discussing things as they're said to be.

Said one to the others, "Now listen, you two,

There is a certain rumor that can't be true

That man descended from our noble race.

That very idea is a disgrace.

No monkey ever deserted his wife,

Starved her babies or ruined her life.

And another thing you will never see:

A monkey build a fence around a coconut tree

And let the coconuts go to waste

Forbidding all the other monkeys to taste.

If I put a fence around this tree,

Starvation would force you to steal from me.

Here's another thing a monkey won't do:

Go out at night and get on a stew,

And use a gun, or club, or knife

To take some other monkey's life.

Yes, man descended, the ornery cuss -

But, brother, he didn't descend from us.”

I must say this poem is actually pretty funny (given that it's not meant as anti-evolutionary propaganda), although, as primatologists and the Machiavellian intelligence hypothesis tell us, non-human primates surely aren’t saints either.

But Penn et al. make their scientific standpoint absolutely clear with the title of their response, which is called:

Darwin’s triumph: Explaining the uniqueness of the human mind without a deus ex machina”

I am particularly excited by the comment of Graeme Halford, professor emeritus at the University of Queensland, Australia, and his colleagues, who write that they

“agree with Penn et al. that the ability to recognise structural correspondences between relational representations accounts for many distinctive properties of higher cognition. We propose to take this argument further by defining both a conceptual and a methodological link between animal and human cognition. The conceptual link is to treat relational processing (Halford et al. 1998a) as dynamic bindings of chunks to a coordinate system in working memory (Oberauer et al. 2007). Such a coordinate system consists of slots and relations between them, and includes relational schemas (Halford & Busby 2007)” (Halford et al. 2008: 138)

This of course reminds me of Karl Bühler’s (1934) coordinate system of subjective orientation which I tried to use as a starting point for a cognitive theory which sees mental representations as intersubjectively overlapping and thus shared systemic spaces in the form of a cognitive coordinate system/frame of reference into which and in which conceptual representations are imported, integrated, unified, and blended. In the future, I will have another look at both Penn et al.’s and Graeme Halford’s claims.

Another ‘interesting’ comment is that of R. Allen Gardner, a Professor of Cognitive and Brain Sciences at the University of Nevada, Reno. Here’s the abstract:

Sound comparative psychology and modern evolutionary and developmental biology emphasize powerful effects of developmental conditions on the expression of genetic endowment. Both demand that evolutionary theorists recognize these effects. Sound comparative psychology also demands experimental procedures that prevent experimenters from shaping the responses of human and nonhuman beings to conform to theoretical expectations.” (Gardner 2008: 135).

What now, you may ask, is ‘interesting’ about this article?. Well let’s take a look at what agrdner had to say about another important Paper on the difference between human and nonhuman cognition, namely Tomasello et al.’s (2005): Understanding and Sharing Intentions: The Origins of Cultural Cognition:

Sound comparative psychology and modern evolutionary and developmental biology (often called evo-devo) emphasize powerful effects of developmental conditions on the expression of genetic endowment. Both demand that evolutionary theorists recognize these effects. Instead, Tomasello et al. compares studies of normal human children with studies of chimpanzees reared and maintained in cognitively deprived conditions, while ignoring studies of chimpanzees in cognitively appropriate environments.” (Gardner 2005: 699)

To me this sounds a bit like flogging a dead horse, but what do I know. (not much about evo-devo, that’s for sure)

At least both feature this nice photo of the test apparatus for chimpanzee Basso, who first was believed to be able to count but, as was found out in 1917, instead was only reacting to the unconscious cues of the experimenter:


Chris of Mixing Memory, John Wilkins of Evolving Thoughts and George Junior have already posted about the article, I hope there are more to come!


Bühler, Karl (1934) Sprachtheorie. Die Darstellungsfunktion der Sprache. Jena: Gustav Fischer.

Gardner, R. Allen (2005): Animal cognition meets evo-devo. In: Behavioral and Brain Sciences 28:5. 699-700.

Gardner, R. Allen (2008): Comparative intelligence and intelligent comparisons. In: Behavioral and Brain Sciences (31:2): 135-136.

Halford, Graeme S..Steven Phillips, and William H Wilson (2008): The missing link: Dynamic, modifiable representations in working memory. In: In: Behavioral and Brain Sciences (31:2) : 137-138.

Penn, Derek C, Keith J. Holyoak. and Daniel J. Povinelli (2008): Darwin's mistake: Explaining the discontinuity between human and nonhuman minds. In: Behavioral and Brain Sciences (31:2): 109-130.

Tomasello, Michael Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll (2005a): Understanding and Sharing Intentions: The Origins of Cultural Cognition. In: Behavioral and Brain Sciences 28:5, 675–691

1 comment:

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