Effect of stress on incidental explicit and implicit memory

Abstract

Objectives: This study examined the effect of stress on memory impairment by inducing acute stress on healthy human participants.

Methods: A total of 46 participants from Hong Kong were randomly assigned to either the stress group (i.e., mental arithmetic with loud noise) or the non-stress group. Within each group, participants were randomly assigned to either the declarative (i.e., explicit; conscious recollection of learned information) or the non-declarative (implicit; retrieved information without conscious or explicit access) memory test. The psychological stress levels of the participants were measured with the Mood Rating Scale immediately before the stressor, immediately after the stressor, and 15 min after the stressor.

Results: The results confirmed the priming effect for the implicit memory recall. However, it did not show any adverse effect of stress on the explicit memory performance. No difference was found between the stress and non-stress groups on almost all the stress levels showing different areas of emotional feelings when measured at different point in time.

Discussion: The verbal functions of the participants may be responsible for producing the priming effect and the failure of the cognitive impairment. Chinese materials should be developed and used to assess the verbal declarative memory performance of Chinese/Cantonese speaking people. Standardization of research paradigms should be developed and more cultural and language awareness is needed in order to promote the reliability and validity of future results.