The construction of category membership judgments: Towards a distributed model

The classification of objects to natural categories displays a great deal of cross-person consensus and within-person consistency. At the same time, categorization also exhibits some degree of within-person instability and cross-person variability. We attempted to gain insight into the stable and variable contributions to category membership judgment by examining confidence judgments and response latency for one’s decision whether an object belongs or does not belong to a given category. According to an extension of the Self-Consistency Model (SCM) (Koriat, 2012), category membership decisions are constructed on the fly on the basis of a small set of cues sampled sequentially from a population of cues associated with the object-category item. This population is largely shared by participants with the same background. The decision is based on the balance of evidence in favor of a positive or a negative response, and confidence is based on the consistency with which that decision was supported across the accessed cues. The results confirmed several predictions: (1) Consensual responses were endorsed with higher confidence and shorter response latency than nonconsensual responses with the differences between the two types of responses increasing with item consensus-the proportion of participants who made the majority response for the item. (2) When the task was repeated several times, confidence and response speed were higher for each participant’s more frequent decision than for the less frequent decision. (3) Results suggested that confidence in a category membership decision reflects the participant’s assessment of the likelihood that the same decision will be reached in future encounters with the item. (4) Finally, the context that was provided for the category membership decision was found to bias the decision reached, but confidence also changed correspondingly, suggesting that context affected the sampling of cues underlying the decision. Altogether, the results provide support for the model, and indicate that confidence and response latency can track the sources of stability and variability in category membership decisions.