Auditory inspection time, intelligence and pitch discrimination

Abstract

Irwin (1984) suggested that the correlation between auditory inspection time (AIT) and IQ was due to AIT being related to pitch discrimination ability. Previous forms of the AIT test have confounded temporal resolution speed and pitch discrimination. In this study, 59 undergraduates and 119 schoolchildren were tested on a new AIT test, pitch discrimination tests and verbal and nonverbal mental ability tests. AIT and IQ correlated at −.45 (verbal) and −.27 (nonverbal) in undergraduates and at −.36 (verbal) and −.26(nonverbal) in children. There was a small but significant correlation between pitch discrimination and IQ scores in children but not in undergraduates. Pitch discrimination tended to correlate with AIT in children but not in undergraduates. Children with high verbal ability appear to have superior auditory inspection times and pitch discrimination abilities. When the effects of pitch discrimination were partialled out, the AIT-IQ correlations were altered very little in either sample. We conclude that the AIT-IQ correlation is due to the AIT being an index of information intake speed. AIT appears not to develop (i.e., to decrease) from age 12.5 to 21.