Differential learning processes for categorization

Abstract

Category learning is a fundamental cognitive process enabling the creation of simplified representations of objects/events. We focus on comparison processes for category learning - learning categories by comparing pairs of exemplars identified to be from the same category (same-class exemplars) vs. pairs from different categories (different-class exemplars). We previously found that these two comparison processes differ dramatically: In the context of learning to categorize novel complex stimuli, training with different-class exemplars depends on pair selection and may require directions for use. On the other hand, same-class exemplars are generally more informative and their use more intuitive. We now report two additional characteristics of learning from same- and different-class pairs. Firstly, while the ability to learn from different-class exemplars develops in late childhood (age 10–14), learning from same-class exemplars seems to be present already in early childhood (6–10). We tested younger and older children and adults on a categorization task, using either same- or different-class exemplar pairs for defining categories. Younger children were unable to execute the different-class comparison strategy. In a related fMRI study, we tested adult participants in three conditions: category learning from same- or from different-class exemplars and a control task, using the same stimuli, but where participants performed a same/different judgment on background shapes. fMRI findings suggest that brain areas associated with complex object processing (V4, LOC), are dramatically more engaged during category learning. At the same time, frontal areas (left and right inferior frontal gyrus) are activated exclusively during the categorization task. Same- vs. different-class exemplar use leads to nuance differences in fMRI activation (when performance level is matched). We conclude that largely the same cortical areas are used for categorization by same- vs. different-class exemplars, though the mechanisms within these areas and degree of their use may differ, underlying different behavioral and developmental effects.

Footnotes

 This study was supported by a