Abstract

Circadian rhythm influences cognitive performance: some people think best in the mornings (morning chronotypes), others at night (evening chronotypes). Furthermore there are large age differences in the distribution of morning and evening chronotypes in the population. Young people (aged 18-23 years) are predominantly evening or neutral types, while older adults are predominantly morning types, and fewer than 3% are evening types. (Yoon, May, & Hasher, 2000). Within the cognitive aging literature the existence of a “synchrony effect” is discussed, meaning that persons tested at their preferred time of time (e.g. morning persons tested in the morning) perform better in a range of cognitive tasks than those tested not at their optimal time of day (e.g. morning persons tested in the evening). However, this effect has never been tested within the field of eyewitness psychology.

This talk will present the results of two experiments examining the effect of circadian rhythm and of matching chronotype and interviewing time on two eyewitness tasks for two age groups (younger adults aged under 30 years and older adults aged 60 and above). The studied variables were completeness and accuracy of eyewitness memory in an interview, and the accuracy of person identification decisions. The results have implications for the creation of practical interventions in forensic interviewing practice, and for the academic study of age differences in eyewitness psychology.