Cognitive Gadgets is an impressive and convincing intervention in the debate on what makes us human. It does not raise essentialist questions, such as “what is human nature?” but attempts to understand why human animals have certain features that make them different from the rest of the animal kingdom. From the very beginning, the author makes however clear that she does not assume “that humans are the only particular animals, or that our particularities make us morally superior” (p. 8). In general, the book foregrounds the human mind (the main disciplinary background of the author is cognitive psychology from an evolutionary point of view), not the three other foci that are the body, the brain, and behavior – all of them complementary with the mind and vice versa. It defends and illustrates a third way between a purely genetic approach of evolution and intelligent design that Heyes calls “cultural evolutionary psychology” and which foregrounds the notion of “cognitive gadget.” In the debate on human evolution, one could consider cultural evolutionary psychology as a new step, after the debates on the distinction between genetics and epigenetics (which affects chromosome structure, but not the ADN structure). It should be clear however that no less than other forms of evolutionary thinking, cultural evolutionary psychology builds on the Darwinian and post-Darwinian idea of variation and selection.

For Heyes, cognitive gadgets are cognitive tools or mechanisms such as, for instance, mindreading or imitation, that are not genetically encoded (nor given by some intelligent design), but that are culturally inherited, that is developed through social interaction. Cognitive gadgets do not refer to “what” we culturally inherit (what Heyes calls the “grist” of the mind), but to “how” we do it (the “mills” of the mind), and throughout the book the cognitive gadget theory is opposed to and compared with the cognitive instinct theory, which insists on the genetic transmission of these mechanisms. For Heyes, “mills” are more important than “grist” (a good recent example of a “grist theory” is meme theory, which claims a strong link between the form and content of a certain item and its capacity to spread and survive), and these “mills” are not theorized in terms of “Big Special” psychological attributes, but as “small ordinary” ones that humans can use in order to build stronger cognitive mindsets via social interaction. In this regard literacy is a key element in human history and evolution, and it is still so recent (reading and writing appeared only five to six thousand years ago) that it helps make a strong claim in favor of non-genetic inheritance of cognitive features. Literacy is simply too recent a phenomenon to have left genetic traces so that its appearance can only be explained through cultural inheritance (the development of which can be seen as the result of a change in the human environment, with for instance stronger interactions between various groups).

The defense of cultural evolutionary psychology is based on hard evidence, and Heyes builds her case by combining three methods: One: the theoretical discussion of the flaws and advantages of the different theories (an example of this is Heyes’s critique of the mirror neurons, which she considers as a kind of black box with little or no explanatory power); two, laboratory tests involving the classic test groups (identical and fraternal twins, other individuals, human and nonhuman animals, always with different ages and in varying contexts); and three, field research to see in vivo how certain cognitive gadgets actually work –provided they can be really tested, which is according to the author not the case of the memetics theory).

In all these cases, Heyes’s thinking remains very nuanced and cautious. The author does not make overgeneralizing claims, she is not looking for a new Grand Theory, and she is perfectly aware of the relative character of the cognitive gadgets (which does not mean that she considers cultural evolutionary psychology itself a weak theory). Cognitive gadgets are at the same time extremely strong and dramatically vulnerable: They are strong because they are very adaptive (since they result from the use of “small ordinary” cognitive tools and so can develop and flourish in all kind of situations, which would not have been the case if they would have been “Big Special” faculties); they are however also very fragile, since the inheritance chain can be broken by a great number of circumstances. Besides, Heyes also recognizes the cultural resistance to the cognitive gadgets theory, as clearly demonstrated in her discussion of Universal Grammar, a typical cognitive instinct theory where the author observes that in spite of all empirical evidence many scholars are not willing to abandon the quest for genetically inscribed universals for the simple reason that they “want” to believe in Universal Grammar, that is to a certain kind of human singularity. Finally, Cognitive Gadgets is certainly not seen as an endpoint, for the author announces new research in domains that will link cognition and emotion: after the work on cultural learning, imitation, mindreading and language, there will be work on ethical issues such as shame and guilt, which are no less contributing to our human particularity than more strictly cognitive elements.

Cognitive Gadgets is a very readable account, even for non-specialists, of one of the most essential questions of scientific research. Its stakes are tremendous, for research as well as society, and therefore must-read for everybody.