Sensorimotor Synchronization and Individual Differences in Intelligence: A Chronometric Perspective on Music Evolution

The ability to adapt movement, such as drumstick-tapping, to synchronize with external rhythmic stimuli has been extensively studied in experimental research, but the causes of individual differences in synchronization error are only beginning to be understood. Several studies have demonstrated that differences in the ability to accurately maintain an equal-interval beat and in the ability to synchronize accurately with an equal-interval pulse are moderately related to measures of general intelligence. Based on a signaling hypothesis of music evolution, and by analogy to mental chronometry research, it was hypothesized that additional time-sensitive cognitive requirements that are present when humans synchronize with groups of other performers may be important causes of the relationship between rhythmic synchronization accuracy and intelligence. This hypothesis predicted (1) that perceptible differences in the quality of improvised creative output by musical non-experts are related to quantitative differences in interval timing and synchronization abilities, and (2) that the relationship between general intelligence and rhythmic synchronization accuracy is increased when elements of stimulus ambiguity and unpredictability are introduced. Two studies demonstrated links among mental traits, timing accuracy, and social perception of creative output. The strongest predictor of average accuracy across synchronization tasks was self-rated prior skill attainment with musical instruments. For particular tasks that included unpredictable phase shifts in rhythmic stimuli, synchronization accuracy was related to differences in general intelligence. Differences in measurable rhythmic timing accuracy were in turn predicted by subjective ratings of the quality of improvised drumming performances. However, because intelligence did not account for additional variability in rhythmic accuracy beyond that accounted for by self-rated musical instrument skill attainment, only weak support was found for the hypothesis that complex background stimuli produced by group musical synchronization were ecologically important as part of a system for signaling mental speed.PsychologyDoctoralUniversity of New Mexico. Dept. of PsychologyMiller, GeoffreyGangestad, StevenRuthruff, EricBoone, Jame