Human reasoning and behavior are ecologically rational when they are adapted to the environment in which humans act. This definition is in stark contrast to classical definitions of rationality, according to which reasoning and behavior are rational when they conform to norms of logic, statistics, and probability theory.

The notion of ecological rationality, that is, the interaction of cognition and environment, is highlighted in Herbert Simon's analogy of a pair of scissors: Human rational behavior is shaped by a pair of scissors, with one blade being the structure of the environment and the other blade the computational capabilities of the actor. This notion highlights two important aspects of the concept of ecological rationality. First, just as one cannot understand the function of scissors by looking at ...