A menagerie of human concepts

Tomasello is one of the most productive proponents of a theoretical stance that characterises behavioural innovation – development – as an expression of a cascade of evolutionary adaptations to selective regimes lost in the mists of time. According to this approach, our ancestors evolved unique capacities for representing others' minds and unique motivations for engaging in collaborative activities. Humans, in Tomasello's view, are a profoundly different kind of being; explanations for human behavioural development are radically discontinuous with the kinds of explanations we might use to explain development in other kinds of creatures, animals who learn through associative learning, for example.  

Tomasello's theory is, in a compound word, anti-Darwinian. Darwin looked at the expressive capacities of animals and saw a continuum, a deep unity between animals and humans; Tomasello, unabashedly, does not. Rather than appeal to developmental processes well-described in other organisms, Tomasello wheels out a veritable smorgasboard of uniquely human cognitive and motivational states: we have a sense of 'We-ness' unique in the world; other animals might display intentional behaviour, but we have uniquely human 'shared intentionality'; humans, but not other animals, display a kind of 'true' joint attention; and so on.  

Tomasello and his colleagues have produced a body of work that is breath-taking in its breadth and originality. There is no question that Tomasello is one of the most creative and productive scientists of our generation. At the end of the book, he urges the reader to consult some of the videos from his experimental work. The reader will most definitely be rewarded by perusal of these stunning visual records in which we see skilled young children displaying their expertise in environments for which they have been well-prepared by their prior learning histories (and apes who are not well-prepared for these testing environments). Apparently, Tomasello sees organisms without regard to their prior learning experiences, relevant or not. Hence, he rejects over a century's worth of psychological study into principles of learning and instead invents a menagerie of novel theoretical concepts that he deems necessary to account for the skills these children display.

The bulk of Tomasello's evidence was gained from the experimental study of children raised in what Joseph Henrich and colleagues termed Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies – these represent less than 5 per cent of the world's population. In Tomasello's theory, development in WEIRD societies is taken as representative (and a gold standard) of all humans, everywhere and everywhen. Moreover, the experiments bolstering this theory of human uniqueness are what has been termed 'Observation-and-Description-Deprived' (ODD, a term coined by Tage Rai and Alan Fiske): almost none of the evidence cited is based in naturalistic observations. Finally, much of the foundation for Tomasello's claim of human exceptionalism is based on comparison of young children raised in WEIRD societies with, typically, much older apes that have been raised in what we (with William Hopkins) have called Barren, Institutional, Zoo, And other Rare Rearing Environments (BIZARRE), without acknowledging that institutionalised rearing, for example, negatively impacts the cognitive and socio-emotional skills of chimpanzees (as it does for humans). It turns out that orphaned apes raised in cages don't act very much like Western middle-class children raised by their parents – how Tomasello can take this as evidence of evolutionary, rather than developmental differences between apes and humans is an enduring mystery.

Therefore, we think this book might have been better titled, 'Becoming a WEIRD human: an ODD theory of ontogeny with BIZARRE comparisons'. 

Reviewed by Kim A. Bard (University of Portsmouth) and David A. Leavens (University of Sussex).