Auditory inspection time: on the importance of selecting the appropriate sensory continuum

Auditory Inspection Time (AIT) is an index of mental speed which correlates moderately with measures of intelligence. This study shows that a loudness version (AIT-L) of an AIT task correlated higher with Ravenʹs Advanced Progressive Matrices (RAPM) than a pitch version (AIT-P). When pitch discrimination ability was partialled out, the correlation between AIT-P and RAPM dropped to 0, while the correlation between AIT-L and RAPM was largely unaffected. The overall pattern of correlations between AIT-P, AIT-L, musical ability, loudness discrimination ability, pitch discrimination ability, and RAPM suggests that AIT-L provides a purer index of mental speed, whereas AIT-P is strongly affected by pitch discrimination ability and musical ability. The results also suggest that the proposed association between sensory discrimination and intelligence might be restricted to the pitch continuum.