Developmental Trends in Visual Search Performance on a Cancellation Task With Various Numbers of Targets: Adults With Intellectual Disabilities, Typically Developed Children, and University Students

― 232 ― The present study examined characteristics of the visual search performance of adults with intellectual disabilities on a cancellation task, and assessed developmental trends by comparing their performance with that of typically developed children and university students. From 55 adults with intellectual disabilities (average age 31.7 years; range 19 to 59 years; 38 men and 17 women), those with Down syndrome were excluded, leaving 26 participants with intellectual disabilities (17 men, 9 women; average IQ, 30.5, range 14 to 52; average MA, 62.8 months, range 32 to 110 months), 20 university students, and 198 typically developed children (101 boys, 97 girls; age range 3 to 12 years). Following instructions, the participants performed 3 types of cancellation tasks with 3 types of targets, and also completed a verbal cognitive test (Picture Vocabulary Test ― Revised) and a visuospatial cognitive test (Raven’s Colored Progressive Matrices Test). The results for the typically developed children and adults revealed 3 developmental stages: ages 3 to 6, 6 to 10, and 11 to adult. Differences were found between target type 1 and types 2 and 3 at all ages; some differences between target types 2 and 3 were observed in the typically developed individuals over 9 years old. A tendency found in the results from the typically developed children’s developmental trends on target types 1 and 2 was also found in the results from the participants with intellectual disabilities. No signifıcant correlations were found between mental age (MA) and any of the target types. However, a correlation was found between the data on cognitive function and the scores on Raven’s Colored Progressive Matrices Test in both the typically developed children and the participants with intellectual disabilities. The results suggest that differences may depend on memory load.