Adults display a category effect in visual search paradigms i.e., when searching an array for the presence of a target letter, subjects detect the letter faster when the array is composed of numbers rather than letters, and vice versa. Groups of 8-yr-old, 10-yr-olds and adults searched for the presence of a target in fields of items that were either of the same or a different category (letter or number) than the target. Highly significant category effects were evident in the search times of all 3 age groups. While search times decreased with development, there was no evidence of an increasing effect of category with age. The feature extraction process that mediates the category effect is apparently fully automated by age 8.