The low-cost hypothesis predicts that the strength of effects of environmental concern on environmental behavior diminishes with increasing behavioral costs. Thus, environmental concern influences environmental behavior primarily in situations and under conditions connected with low costs and little inconvenience for individual actors. In a first step, we develop and specify this hypothesis. Referring to two procedures, we then test it on the basis of an environmental survey of a random sample of 2307 respondents from the German population. The empirical evidence is positive. The low-cost hypothesis is not confined to the area of environmental research. It points to general limits of attitude-research (in high-cost situations) and to general limits of rational-choice theory (in low-cost situations), and suggests a strategy for integrating research in social psychology, sociology, and economics.

A conflict game simulating social traps in which a collective good can be provided by a volunteer is discussed and some solution concepts are analyzed. There is a greater incentive for “free riding” than for the production of the collective good at the cost of the volunteer. However, if everybody defects, all players will lose. Such a result is frequently produced by “diffusion of responsibility” as described by Darley and Latané (1968). In contrast to other social traps, a dominant strategy does not exist. Also, the mixed-equilibrium strategy yields very low payoffs. The expected gain is not greater than the payoff achieved by the nonequilibrium maximum strategy. Superrationality might be a way out of the trap. However, this concept lacks the desirable equilibrium property. Only in the free communication version of the game can a definitive answer to the question of a rational strategy be given.

On the basis of an empirical study in Switzerland and Germany, it is shown that there are considerable inconsistences between citizens' environmental attitudes and their behavior. A disaggregation of the multidimensional concept of `environmental behavior' and a look at this behavior from the viewpoint of rational actors, are proposed as two perspectives from which to get a better understanding of these inconsistencies. Empirical analyses (making use of these two perspectives) lead to an identification of three cognitive strategies by which individual actors try to harmonize and to reconcile seemingly incongruent environmental attitudes and behaviors. These strategies can be subsumed under the short-hand labels `attention-shifting strategy', `low-cost strategy' and `subjective-rationality strategy'.

Digits in statistical data produced by natural or social processes are often distributed in a manner described by ‘Benford's law’. Recently, a test against this distribution was used to identify fraudulent accounting data. This test is based on the supposition that first, second, third, and other digits in real data follow the Benford distribution while the digits in fabricated data do not. Is it possible to apply Benford tests to detect fabricated or falsified scientific data as well as fraudulent financial data? We approached this question in two ways. First, we examined the use of the Benford distribution as a standard by checking the frequencies of the nine possible first and ten possible second digits in published statistical estimates. Second, we conducted experiments in which subjects were asked to fabricate statistical estimates (regression coefficients). The digits in these experimental data were scrutinized for possible deviations from the Benford distribution. There were two main findings. First, both digits of the published regression coefficients were approximately Benford distributed or at least followed a pattern of monotonic decline. Second, the experimental results yielded new insights into the strengths and weaknesses of Benford tests. Surprisingly, first digits of faked data also exhibited a pattern of monotonic decline, while second, third, and fourth digits were distributed less in accordance with Benford's law. At least in the case of regression coefficients, there were indications that checks for digit-preference anomalies should focus less on the first (i.e. leftmost) and more on later digits.

In two experiments, the existence and extent of altruistic reciprocity is exploredin the context of a simple experimental game, “the sequential dictator.” Findings show that altruistic reciprocity is frequent and robust, and the reciprocity norm does not erode if stakes are raised. Implications of the findings for social theory and further empirical research are discussed.