Processing Time Declines Exponentially during Childhood and Adolescence.

One hundred ninety-two 7.5- to 21-year-olds and 384 adults (17- to 43-years-olds) were tested on six speeded tasks: a) a simple response time task in which they released a button upon presentation of a stimulus, b) a tapping task in which they pushed a button as rapidly as possible for 5 s, c) a pegboard task in which they transferred 10 pegs from one row to another, d) a modified form of the coding subtest from the Wechsler Intelligence Scale for Children (WISC), e) a matching task in which they judged if pairs of pictures were identical physically or in name, and f) a mental addition task in which they judged the accuracy of problems such as 2+3=6