Neuroticism is correlated with drift in serial time interval production

Low neuroticism and high intelligence are both related to lower intertrial variability in reaction time tasks. However, intelligence and neuroticism are weakly related traits, which suggests that they may be related to different sources of timing variability. The relation between intelligence and timing variability has recently been investigated using isochronous serial interval production (ISIP). This is a simple, automatic timing task where participants first synchronize movements with an isochronous sound sequence and then continue with self-paced production of a sequence of intervals with the same inter-onset interval (IOI). For all IOIs, local interval-to-interval variability correlated strongest with intelligence. The purpose of the present study was to test whether neuroticism, in contrast, is related to the non-local component of ISIP variability, i.e. drift or gradual changes in response IOI. We found a significant correlation of r = 0.42 between drift and neuroticism, thereby confirming the hypothesis. We suggest that this finding reflects that individuals high on neuroticism have more frequent slips in top–down cognitive control mechanisms. These cognitive failures may in turn interfere with the processing of previously produced intervals in short-term memory, which gives an unstable IOI in the ISIP task, i.e. drift.