The effect of pain on reference memory for duration.

Previous research has consistently reported that pain related stimuli are perceived as lasting longer than non-pain related ones, suggesting that pain lengthens subjective time. However, to date, the investigation has been limited to the immediate effects of pain on time perception. The current study aims to investigate whether pain affects how a duration is recalled after a period of delay. In two experiments, participants were asked to complete four temporal generalisation tasks, where they were required first to remember the duration of a standard tone (learning phase) and then to compare the standard duration to a series of comparison durations (testing phase). Using a 2 × 2 design, the four tasks differed in terms of whether participants were exposed to a painful or non-painful stimulus during the learning phase, and whether the testing phase started immediately or 15 min after the learning phase. Participants were exposed to low pain in Experiment 1 and high pain in Experiment 2. Two possible results were expected: pain could decrease temporal accuracy, because pain disrupts cognitive processes required for accurate timing, or pain could increase temporal accuracy, because pain facilitates memory consolidation. Contrary to expectations, results from both Experiments indicated that participants' temporal performances were similar in the pain and no-pain conditions when testing occurred 15 min after the learning phase. Findings, therefore, suggest that pain neither disrupts nor enhances long-term memory representations of duration.