Rationality without optimality: Bounded and ecological rationality from a Marrian perspective

Ecological rationality provides an alternative to the view that rational responses toenvironmental uncertainty are optimal probabilistic responses. Focusing on the ecological rationality of simple heuristics, critics have enlisted Marr's levels of analysis and the distinction between function and mechanism to argue that the study of ecological rationality addresses the question of how organisms make decisions, but not the question of what constitutes a rational decision and why. The claim is that the insights of ecological rationality are, after the fact, reducible to instances of optimal Bayesian inference and require principles of Bayesian rationality to explain. Here, I respond to these critiques by clarifying that ecological rationality is more than a set of algorithmic conjectures. It is also driven by statistical commitments governing the treatment of unquantifiable uncertainty. This statistical perspective establishes why ecological rationality is distinct from Bayesian optimality, is incompatible with Marr's levels of analysis, and undermines a strict separation of function and mechanism. This argument finds support in Marr's broader but largely overlooked views on information processing systems and Savage's stance on the limits on Bayesian decision theory. Rationality principles make assumptions, and ecological rationality assumes that environmental uncertainty can render optimal probabilistic responses indeterminable.