Age-related changes in time discrimination: The involvement of inhibition, working memory and speed of processing

Background: Researchers have devoted much effort in trying to understand how and why our subjective experience of time changes across the adult life-span. The cognitive apparatus that supports timing is integrally entwined with those supporting other cognitive processes including working memory, inhibition and speed of processing. Methods: One-hundred-eighty adults ranged from 19 to 87 years old participated in the study. A time discrimination task, with two standard intervals (short standard = 500 ms; long standard = 1500 ms) was used. Moreover, N-back and Stroop tasks were used to assess working memory, inhibition and speed of processing. Results: Data were analysed with a multilevel mixed model approach. Accounting for between-subject variability, we compared models in order to assess the better fit using chi-square likelihood-ratio test, Akaike information criterion and the Bayesian information criterion. Results showed a significant interaction between age, standard interval, comparison interval and speed of processing. Conclusion: Our study confirmed that younger participants were generally more accurate across conditions than older ones; we also showed that performance depended indeed on intervals, but also on speed of processing abilities across age