Natural Rationality | decision-making in the economy of nature


Evolutionary cognitive neuroscience and evolutionary neuroeconomics

In a review paper in Evolutionary Psychology(pdf), Krill, Platek, Goetz and Shackelford present an overview of evolutionary cognitive neuroscience (ECN). Whereas evolutionary psychology and cognitive neuroscience tended to study the adapted mind without concerns for the brain, or the brain without concerns for its evolutionary history, this burgeoning field tries to fill the gap. Krill et al. 's paper is a pretty good overview of methods and issues in ECN. Platek and Shackelford, with other researchers, are also publishing two books on ECN:

  • Platek, S.M. and Shackelford, T.K. (under contract). Foundations in EvolutionaryCognitive Neuroscience. Cambridge University Press, Cambridge, UK.
  • Platek, S.M., Keenan, J.P., and Shackelford, T.K. (Eds.). (2007). Evolutionary Cognitive Neuroscience. Cambridge, MA: MIT Press.
One strenght of ECN is that it does not rely on a functionalist conception of mind, that is, the idea that "what makes something a mental state of a particular type does not depend on its internal constitution, but rather on the way it functions, or the role it plays, in the system of which it is a part."(SEP definition). ECN study the hardware, not the software. Instead of postulating functional modules, ECN try to identify adapted brain mechanisms.

ECN could certainly be a good teacher for neuroeconomics. The Standard View of neuroeconomics assumes that researches in this field explain how humans and other animals follow (or fail to follow) standards of rationality such as decision theory and game theory:

The research topics studied by neuroeconomists fall into two major categories: (i) identifying the neural processes involved in decisions in which standard economic models predict behaviour well; and (ii) studies of ‘anomalies’ where the standard models fail.
(Zak, P. J. (2004). Neuroeconomics. Philos Trans R Soc Lond B Biol Sci, 359(1451), p. 1740)

Neural mechanisms account for the formal rationality of irrationality of behavior. Although this conception is important, I think that another one would be relevant. According to what we might call The Adaptive View, mechanisms uncovered by neuroeconomic researches are (or at least could be) adaptations to ecological conditions. In this view, neural mechanisms account for the natural rationality of behavior. Just as a bird’s wing embodies information about gravity and air viscosity, brain functioning embodies information about the social and physical environment. Robust findings in neuroeconomics can be construed as candidate for adaptive explanations: e.g. if there is a striking difference between risk and ambiguity at the neural level (studies suggest that ambiguity - lack of information about the probability - elicit more activity in the amygdala, cf Hsu et al, Science, 2005), than maybe there is an adaptive function for such a dissociation. Of course, other hypothesis are necessary for these questions, but evolutionary neuroeconomics should be an important research program. Again, more collaboration is needed: the ECN paper do not mention anything about neuroeconomics, and neuroeconomists often neglect evolution.

At the end of the 19th century, American economist Thorstein Veblen wondered "Why is Economics Not an Evolutionary Science" (Veblen, 1898). The reason was that the whole conception of economic agency was based on desire-satisfaction. Veblen argued that economics should be a science of human action, not desire, coherent with biology, anthropology and psychology, not vaguely inspired by physics. One might also ask now "Why is Neuroeconomics Not an Evolutionary Science". Neuroeconomics may be too focused on preferences, and not enough on choice behavior and adaptation.