(p. 127) Evolutionary neurobiology and cognition
Understanding brain evolution has obvious implications for psychology and cognition. One of the most important is that it reminds us not to expect perfection in our evolved cognitive architecture. Evolutionary design is never perfect because nothing is ever designed from scratch: evolution tinkers with what is already present. In this sense, evolutionary processes are constrained. At the same time, they are also liberated by the vast periods of time over which they operate. Cost-effective, but non-obvious, often somewhat messy, solutions, are the result. This is as true of the brain as it is for any other organ or anatomical structure, which means that understanding the evolved architecture and function of the brain is essential if we are to frame our theories of cognitive evolution appropriately.
For example, most of evolutionary history has been spent perfecting the perceptual and action-based mechanisms that allow an animal to deal effectively with its environment (Brooks, 1999)—as Barton points out, the fundamental behavioural function of the brain is to move bodies around the world in an adaptive manner, rather than act as a “disembodied, logical reasoning device” (Clark, 1997). Given this, it should be apparent that, over evolutionary time, the perception—action mechanisms that are in place will inevitably constrain the manner in which higher-level cognitive processes evolve and help to explain why cognition is structured in a particular way. The recent discovery of mirror neurons in the motor system of primates, and the implications they hold for the evolution of more sophisticated forms of social cognition, are a case in point, as discussed by Rizzolatti and Fogassi. Jellema and Perrett put forward a similar argument with respect to aspects of the visual sensory system. It is clear that paying attention to the evolution and function of perceptual and motor processes will shed light on how and why we think in the ways that we do.
Moreover, it is evident that an understanding of brain evolution helps to refocus our attention on the selection of particular networks and systems within the brain. The influential ‘social brain’ hypothesis (Dunbar, 1998) has, to date, focused attention on the neocortex due to its evolutionary expansion within the primate order. Both Barton and Panksepp, however, emphasise the importance of moving away from a focus on one particular brain area to one where the “social brain” is seen as a distributed (p. 128) neural (and neurochemical) system, in which several of the pathways involved can be traced back to our more distant mammalian ancestors, and are thus very ancient systems indeed.
Finally, it is also clear that, as well as being constrained by brain architecture and perceptuo-motor systems, cognitive structures will themselves be constrained by evolutionary processes. As Todd and Gigerenzer argue, we should expect humans and other animals to show ‘ecological rationality’, rather than the economists' perfect rationality. Solutions which, in the confines of certain laboratory set-ups, appear clunky or prone to mistakes may still be good enough to produce adaptive solutions under more evolutionarily relevant conditions. Expecting highly tuned perfection in either brain processes or cognitive processes, and theorizing on that basis, is simply not an evolutionarily sound position to take. Instead, we need to roll up our sleeves and get into the messy stuff of real life.
Brooks, R. A. (1999) Cambrian Intelligence: The Early History of the New AI. MIT Press, Cambridge, MA.
Clark, A. (1997) Being There: Putting Brain, Body, and World Together Again. MIT Press, Cambridge, MA.
Dunbar, R. I. M. (1998) The Social Brain Hypothesis. Evolutionary. Anthropology 6: 178–190.