The effect of time delay on young adults' prospective memory

This study examined the effect of time delay on prospective memory (PM) by manipulating the interval between encoding and retrieval of an event-based PM task. Seventy-four participants were randomly assigned to one of three delay conditions (immediate, 1-day, and 1-week) and were instructed on a classic dual event-based PM task during the first online experimental session. They were then asked to undertake the PM task after the designated delay period based on their assigned experimental condition in the second online session. Significant main effects of delay on PM performance (measured in terms of remembrance and accuracy) were found. Post hoc test results revealed that, when compared to the no-delay condition, the 1-week delay condition impacted both remembrance as well as accuracy of the PM task, while the 1-day delay condition affected only accuracy but not remembrance. This study provides a unique contribution to the PM literature by including longer delay intervals between PM encoding and retrieval to improve ecological validity. In future research, this factor should be considered when studying PM in different groups of participants, including children, older individuals, and clinical populations.