Social behavior is determined by multiple and interactive forces. This persuasively simple insight is still not fully appreciated within psychology. People have argued (and some continue to argue) about nature-nurture percentages, attitude-behavior relationships, and person vs. situation causes.

Historical unfolding of the person-situation controversy

1. Lewin's critique of the "Aristotelian" trend in psychology and his declared situationism. Lewin happened to be one of the fathers of social psychology, so social psychology has a strong situationist bent as well.

2. The misunderstood analysis by Heider (1958) of how ordinary people explain behavior (allegedly by reference to either person causes or situation causes).

3. Mischel's (1968) critique of trait research, suggesting that (a) .20 correlations between two behaviors or a trait and a behavior are theoretically negligible and not worth studying and that (b) situational influences on behavior are stronger.
   Mischel's doubts about the cross-situational consistency of traits triggered a long and relentless controversy. Personality researchers defended the value of trait thoeries and related research on several fronts, among them:
   • 1-item "tests" (one single behavior correlated with another single behavior) can never yield high correlations; aggregation is the solution (because traits are general causal factors they can be identified only across many instances, after averaging out all the other causal factors that impinge on the behaviors);

   • situations and traits are impossible to compare; studies trying to pit one against the other are always subject to criticism that one had been "favored";

   • When one compares a decent number of studies with "situation" manipulations and a comparable number of studies with trait measures, the average effect size is quite similar (already shown by Funder & Ozer, 1983);

4. In response to these replies, situationists pointed to small situational manipulations that had large effects (while admitting that some large manipulations had small effects; see Ross & Nisbett, 1991). By comparison, they claimed, there are no large effects from personality traits. (Not true, argues Goldberg.)

5. As some kind of conclusion one might say that traits and situations virtually always interact with each other. However, exactly what that means (and implies for research practice) has not been made explicit.

6. The consequences of this controversy have been partly negative (e.g., social and personality psychologists still show a lot of in-group/out-group tendencies and some animosities) and partly positive (e.g., more attention to measurement issues, interactionism, multiple determinism).

7. Ross and Nisbett highlight the contrast between scientific view and lay view (charging the lay person with the ugly label of "dispositionist"). However, the data are quite weak in support of this dispositionist charge. In a couple of weeks we will return to this point.

   Notes on interactionism

   Some further thoughts on the person-situation dichotomy and its only reasonable alternative, interactionism.

   First, person factors include traits but also include many more, and more complex, mechanisms, such as sensitivity to norms, responsiveness to communication, etc. Some of these factors are present in almost every person in a given culture, but they are not traditional "individual difference" factors because everybody has them.

   Second, some situation factors are physical and directly exert some causal influence on behavior (e.g., heat, crowdedness). But many situation factors are only efficacious to the extent that people interpret them a certain way. The same physical utterance can be taken as a joke or an insult, and only the latter will be a causal antecedent to aggression.

   Third, the distribution of causal influence is sometimes less important than an analysis as to which causal factor is most likely to change the behavior. In the Milgram experiment, for example, it is easier to remove the authority figure than to wipe out all subjects' sensitivity to norms of obedience, even though both factors critically contribute to the obedient behavior. So sometimes we treat a phenomenon as if it were due to a "main effect" even though the causal analysis shows numerous interactions.

   Fourth, causal analysis can be focused on many levels of analysis, such as on broad societal structures, on interpersonal patterns, on individual differences, or on universal physiological substrates. None of these levels necessarily compete with each other for causal influence. Which factor is important for description and explanation depends on the question being asked - so, ultimately, personality and social psychologists have to realize that they often ask different questions rather than offering competing answers to the same question.