Neutral auditory words immediately followed by painful electric shock may show reduced next-day recollection.

In this study, we investigated the effect of experimentally delivered acute pain on memory. Twenty-five participants participated in experimental sessions on consecutive days. The first session involved a categorization task to encourage memory encoding. There were two conditions, presented in randomized order, in which participants listened to a series of words, which were repeated three times. In one condition, one-third of the word items were immediately followed by a painful electrical shock. This word-shock pairing was consistent across repetition and the pain-paired items were presented unpredictably. In the other condition, all word items were not associated with pain. Response times over these repeated presentations were assessed for differences. Explicit memory was tested the following day, employing a Remember-Know assessment of word recognition, with no shocks employed. We found evidence that recollection may be reduced for pain-paired words, as the proportion of correct Remember responses (out of total correct responses) was significantly lower. There were no significant reductions in memory for non-pain items that followed painful stimulation after a period of several seconds. Consistent with the experience of pain consuming working memory resources, we theorize that painful shocks interrupt memory encoding for the immediately preceding experimental items, due to a shift in attention away from the word item.

Psychometric and electrodermal activity data from an experimental paradigm of memory encoding with some items periodically followed by painful electric shock.

How pain influences explicit memory is an active area of investigation, and next-day recognition was the primary outcome of this experiment. The data reported here were secondary measures of psychometrics to quantify interindividual variability between subjects and measure electrodermal activity (EDA) changes in response to experimental stimuli. Reliable EDA responses following painful electric shocks were obtained in the Learning portion of the experiment. During next-day testing, however, no reliable EDA responses were elicited, including to previously pain-paired experimental items.