We critique the distinction Byrne makes between strong causes and enabling conditions, and its implications, on both theoretical and empirical grounds. First, we believe that the difference is psychological, not logical. Second, we disagree that there is a strict Third, we disagree that it is easier for people to generate causes than counterfactuals.

We emphasize the value of the socio-ecological approach in addressing the problem of population variances. The socio-ecological perspective studies how social and natural habitats shape human behaviors, and are in turn shaped by those behaviors. This focus on system-level factors is particularly well-suited to studying the origins of group differences in human behavior.

Humans appear to follow normative rules of inductive reasoning in "premise diversity tasks" that is, they know that dissimilar rather than similar evidence is better for generalising hypotheses. In three experiments, we use a "hypothesis limitation task" to compare a related inductive reasoning skill knowing how to limit hypotheses by using a negative test strategy. Participants are told that one category member has some property (e.g. Dogs have a merocrine gland) and are asked what evidence they would test to ensure (...) that either all (generalisation) or only (limitation) category members have that property (e.g. All/Only mammals have merocrine glands; tests: wolf, bull, crocodile). Despite participants' reluctance to use negative tests in the Wason 2-4-6 task and other reasoning tasks, participants do use normatively correct negative tests in the hypothesis limitation task as often as they use diverse positive tests in the premise diversity task. Moreover, when given a hypothesis limitation task before a rule evaluation task (similar to the 2-4-6 task), the use of negative tests increases. Thus, when testing hypotheses, people can and do use the right kind of test strategy for the task. (shrink)

When base rates are learned and used in an experiential manner subjects show better base rate use, perhaps because the implicit learning system is engaged. A causal framework in which base rates are relevant might also be necessary. Humans might thus perform better on more ecologically valid tasks, which are likely to contain those three components.