Characteristics of visual search and brain activity in Japanese elementary schoolchildren: A cross-sectional study using functional near-infrared spectroscopy

Visual search is a crucial behavior that supports learning, work, and other daily activities. However, the specific characteristics of visual search and the associated brain activity in Japanese elementary school children have not been thoroughly investigated. This study aimed to elucidate these characteristics by examining visual search behavior and prefrontal cortex (PFC) activity in this population. Seventy-one schoolchildren were divided into three age groups (7-8 years, 9-10 years, and 11-12 years). Their PFC activity was measured using functional near-infrared spectroscopy (fNIRS) while they performed a cancellation task under two conditions: a structured array and a random array. Visual search behavior was evaluated using multiple indices, including the number of correct responses and the ratio of intersections, analyzed from multiple perspectives. The number of correct responses reflecting visual search processing ability, was significantly higher in the older age group. The ratio of intersections, an index of the systematicity of visual search, was significantly lower in the structured array condition compared to the random array condition, but only in the 11-12-year-old group. Additionally, this group showed significantly greater PFC activation during the structured array condition than during the random array, whereas the younger groups exhibited the opposite pattern. These findings suggest a developmental relationship between the systematicity of visual search and changes in PFC activity. A multifaceted approach combining physiological and behavioral measures may offer deeper insights into the characteristics of visual search in elementary school children.