Ecological Rationality

Definition

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.

History

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 a single blade, one cannot understand human cognition by studying either the environment or cognition alone. Second, the concept of ecological rationality can be employed to evaluate more than just people's behavior; it is additionally presumed that people's reasoning is the result of an adaptation of the individual to his or her environment.

The concept of ecological rationality has been strongly influenced by the psychologist Egon Brunswik's work on human perception. Brunswik argued that human perception cannot be understood when it is studied in a nonrepresentative laboratory setting that eliminates the ecological structure of real-world environments. When following the common experimental practice of using a factorial design, objects are constructed or selected such that the cues describing the objects, which are the focus of interest, are independent of each other. This procedure does not acknowledge that the same cues are often correlated with each other in everyday life and that human perception could take these correlations into account. Ignoring these environmental aspects in an experimental setting has profound consequences: It severely limits the generalizability of the results and, in particular, obscures the adaptation and ecological rationality of cognitive mechanisms.

According to Brunswik, to understand cognition one needs to explore the characteristics of the environment on which cognition is based. This point has inspired many researchers, including John R. Anderson, James J. Gibson, Gerd Gigerenzer, David Marr, and Roger Shepard. Anderson, for instance, argues that any study of psychological mechanisms should be preceded by an analysis of the environment. His point is that such an analysis may help to identify the cognitive mechanisms that underlie human behavior. This process can be problematic, however, given that different mechanisms often predict very similar behavior. Therefore, the behavior alone does not allow one to infer unambiguously which of the mechanisms produced that behavior. However, when one also analyzes what mechanisms are able to produce adaptive behavior in a specific environment, the set of mechanisms can be reduced. If a limited set of adaptive mechanisms is focused on to explain cognition, the identification of the most adequate mechanism is simplified.

[Page 274]The identification of cognitive mechanisms that govern human behavior can further be improved when it is taken into account that people's reasoning is constrained by limited resources, such as time, memory, or computational power. Faced with these limitations, it is reasonable to assume that humans will aim for solutions to a problem that do not require many resources. Thus, when two potential cognitive mechanisms are able to produce adaptive behavior in a specific environment, it is likely that humans will apply the mechanism that requires the least amount of resources. In this vein, researchers such as Gigerenzer, Peter Todd, and the ABC Research Group have argued that people apply fast and frugal heuristics that are adapted to an environment. A heuristic is frugal when it does not require much information, and it is fast when it relies only on simple computations. From the perspective of ecological rationality, a heuristic that does not require many resources and, in addition, is able to solve a problem well is a very promising candidate to describe the cognitive process that underlies human behavior.

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