The Effects of Emergency Siren Noise Stress on State-Dependent Memory

Abstract

Acute stress is known to impose both adaptive and maladaptive effects on memory in the form of memory enhancement or impairment. Here, we investigated the effects of an acute noise stressor on the memory phenomenon, state-dependent memory which postulates when encoding and retrieval are performed in an identical state, memory will be improved. Currently, a gap in the literature exists in understanding the relationship between noise stress and state-dependent memory. The present study states two hypotheses. First, if participants encode and retrieve information both in a noise stress induced state, then a state-dependent memory effect exists for noise stress. Alternatively, noise stress exposure may be a detriment to encoding and retrieval facilitating in impairing memory and thus, a state-dependent memory effect does not exist. Eleven fire department personnel were placed in one of four groups: stress-stress, stress-neutral, neutral-neutral or neutral-stress. Participants were exposed to either an emergency siren noise audio or beach waves audio while simultaneously encoding information from a narrative. After a series of distractor tasks, participants once again were exposed to either the emergency siren noise audio or beach waves audio while simultaneously retrieving the previously learned narrative. Memory was measured by the number of correct and forgotten narrative items by a free recall. The study revealed no statistical significance between either the number of correct or forgotten items and any of the groups. Upon examining the median scores, a pattern emerged suggesting an effect where the stress-stress group (Mdn = 10) followed by the neutral-neutral group (Mdn = 8) correctly recalled the most items. Also, forgotten memory scores seemed to be on average higher than the correctly recalled memory scores. The research discusses possible explanations for the results and implications towards professionals where noise stress is inevitable, but an intact memory is integral to perform living saving tasks.