The meaning of rational behaviour depends critically on the context of the situation and there are generally many ways of being rational. We distinguish axiomatic rationality, as used by economists, from evolutionary rationality, was practiced by people. Many so-called 'biases' are responses to the complex world of radical uncertainty. Evolution in this uncertain world has led characteristics which are primarily adaptive to become embodied in human reasoning. Humans are successful at adapting to the environment in which they find themselves, and have not evolved to perform rapid calculations of well-defined problems at which computers excel. This is because the problems which humans face, whether sparkling at dinner party conversations or conducting international trade negotiations, are not well-defined problems amenable to rapid calculation.
-John Kay and Mervyn King, Radical Uncertainty: Decision-Making Beyond The Numbers