Complexity. In general individual decision makers must be assumed to have multidimensional values which attach nonmonetary subjective cost or value t… - Vernon L. Smith

One of the most intriguing discoveries of experimental economics is that (1) as we have seen, people invariably behave non-cooperatively in small and large group ‘impersonal’ market exchange institutions; (2) many (up to half in single play; over 90% in repeat play) cooperate in ‘personal’ exchange (two-person extensive form games); (3) yet in both economic environments all interactions are between anonymous players.

Microeconomics, including the study of individual choice and of group choice in market and nonmarket processes, has generally been considered a field science as distinct from an experimental science. Hence microeconomics has sometimes been classified as "non-experimental" and closer methodologically to meteorology and astronomy than to physics and experimental psychology (Marschak, 1950, p. 3; Samuelson, 1973, p. 7). But the question of using experimental or nonexperimental techniques is largely a matter of cost, and generally the cost of conducting the most ambitious and informative experiments in astronomy, meteorology, and economics varies from prohibitive down to considerable. The cost of experimenting with different solar system planetary arrangements, different atmospheric conditions, and different national unemployment rates, each under suitable controls, must be regarded as prohibitive.

In economics the tendency of theory to lag behind observation seems to be endemic, and, as theorists, few of us consider this to be a "terrible state." But as noted by Lakatos (1978, p. 6), "where theory lags behind the facts, we are dealing with miserable degenerating research programmes."