2.2 Temporal "g" (general intelligence)
The relation between general intelligence (psychometric g) and temporal resolution capacity of the central nervous system was examined by assessing performance on eight different temporal tasks in a sample of 100 participants. Correlational and principal component analyses suggested a unitary timing mechanism, referred to as temporal g . Performance on single temporal tasks and individual factor scores on temporal g were substantially correlated with factor scores on psychometric g. Additional stepwise multiple regression analysis and commonality analysis showed that performance on temporal information processing provides a more valid predictor of psychometric g than traditional reaction time measures derived from the Hick paradigm. Findings suggest that temporal resolution capacity of the brain as assessed with psychophysical temporal tasks reflects aspects of neural efficiency associated with general intelligence.
The emergence of a very strong single component in the nonmusician group may be interpreted as evidence for a prominent source of shared variance among various aspects of temporal information processing. Since perceptual timing tasks require processing changes in information over time, several authors (e.g., Burle & Bonnet, 1997, 1999; Rammsayer & Brandler, 2002; Surwillo, 1968) put forward the idea that a general internal timing mechanism in the brain is responsible for various aspects of temporal information processing such as rhythm perception or interval timing. More specifically, performance on interval timing is often explained by the general assumption of a hypothetical internal clock based on neural counting (e.g., Creelman, 1962; Gibbon, 1977; Rammsayer & Ulrich, 2001; Treisman, Faulkner, Naish, & Brogan, 1990).