On the relationship between general fluid intelligence and psychophysical indicators of temporal resolution in the brain

Abstract

One possible cause for the higher speed of information processing of more intelligent individuals may be that higher-intelligence scores are associated with higher temporal resolution capacity of the brain. Therefore, the present study was designed to investigate the potential relationship between timing performance and general fluid intelligence. For this purpose, a sample of 100 participants was divided into a lower-IQ and a higher-IQ group according to below and above median scores on Cattel's Culture Fair Intelligence Test Scale 3. Experimental tasks were duration discrimination of auditory intervals in the range of milliseconds and seconds, temporal-order judgments (TOJ), and auditory flutter fusion (AFF). Performance on duration discrimination of both filled and empty intervals in the range of milliseconds was significantly better for the high-IQ than for the low-IQ group. No IQ-related differences could be shown for temporal discrimination of intervals in the range of seconds, TOJ, and AFF. Furthermore, stepwise multiple regression analysis revealed that combining performance on duration discrimination with filled and empty intervals in the range of milliseconds accounted for 22% of the total variance of general fluid intelligence. Findings suggest that brain mechanisms specifically involved in discriminations of extremely brief intervals represent a sensitive indicator of general fluid intelligence.