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.
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