Examining Perceptual and Categorical Influences on Visual Working Memory

Visual working memory (VWM) refers to the limited capacity storage of visual information used for behaviors like problem-solving, planning, or reasoning. VWM is a crucial component of cognition, and individual differences in capacity during childhood have been linked to outcomes in academic achievement, fluid intelligence, and socioemotional development. VWM increases in capacity and precision throughout development. Very few studies have investigated what factors influence changes in VWM abilities in preschool-aged children. The first goal of this study was to examine VWM precision development in this age-range. This was accomplished by administering a delayed estimation task. In this task, children touched a color wheel to indicate the color of an item in memory from a two-item array. Mixture modeling was used to measure the likelihood of reporting the target color and precision of the color represented in memory. The second goal of this project was to investigate the underlying neural, perceptual, and categorical mechanisms of VWM development. To measure perceptual mechanisms, children completed a discrimination task where they touched a color wheel to indicate the color of a visually presented color. For categorical mechanisms, children completed production and comprehension tasks for colors. To assess comprehension, children touched a color wheel to indicate the location of ‘blue’ and ‘green’. Lastly, for production, children provided ‘blue’ or ‘green’ labels for stimuli that were randomly sampled between canonical blue and green color values. Forty-four children aged 36-48 months completed these tasks across two sessions, as well as nine adults. Results showed deactivation across the delayed estimation and discrimination tasks in left postcentral gyrus, as well as activation for both in right middle temporal gyrus. In addition, right inferior gyrus was more strongly activated for the discrimination task, and left inferior frontal gyrus was more strongly activated for the delayed estimation task. Activation during both tasks was associated with behavioral measures such as the location of children’s color category boundary during production, suggesting a relationship between VWM precision and perceptual and categorical mechanisms.