We investigated the influence of stimulus base rates on the Implicit Association Test . Using an East/West-German attitude-IAT, we demonstrated that both overall response speed and differential response speed underlying IAT effects depend on the relative frequencies of the stimulus categories. First, when those stimuli that are more common in reality also occurred more frequently in the stimulus list, response speed generally increased. Second, IAT effects increased when congruent blocks profited from the compatibility of frequency-based response biases , whereas IAT (...) effects decreased when incongruent trial blocks profited from response compatibility. These findings demonstrate that the stimulus context moderates the magnitude of the IAT effect. Simultaneously, they highlight the need to explore the extent to which implicit measures reflect properties of the task or the environment rather than attributes of test-takers. (shrink)

Many philosophers have challenged the ideal of value-free science on the grounds that social or moral values are relevant to inferential thresholds. But given this view, how precisely and to what extent should scientists adjust their inferential thresholds in light of nonepistemic values? We suggest that signal detection theory provides a useful framework for addressing this question. Moreover, this approach opens up further avenues for philosophical inquiry and has important implications for philosophical debates concerning inductive risk. For example, the signal (...) detection theory framework entails that considerations of inductive risk and inferential-threshold placement cannot be conducted in isolation from base-rate information. (shrink)