The impact of psychosocial stress and biological sex on false recognition memory
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University of Cape Town
Based on the premise that both the hippocampus and pre-frontal cortex are affected by cortisol and involved in declarative memory processes, the current research aimed to confirm that psychosocial stress can lead to increased rates of false recognition memory errors in humans. In addition, it attempted to show that false recognition error rates differ depending on biological sex and the original stimulus type, thus extending and validating the research done by Gallo and colleagues (2004) on material specificity in false memory. Participants in a Stress group (15 males and 13 females) were exposed to a procedure designed to induce mild psychosocial stress, whereas participants in a Relax group (15 males and 14 females) were exposed to a period of relaxation. Salivary cortisol, heart rate, and subjective self-report measures were used to determine participants' stress levels. All participants completed a false memory task, entailing 3 different recognition tests, on 2 consecutive days. Results showed that under both stressful and non-stressful conditions, pictures were better remembered than words, and that this effect was not mediated by biological sex. However, false recognition errors were greater for pictures compared to words, and neither experimental condition nor biological sex mediated this effect. It was also found that the amount of false memory recognition errors made was not affected by the presence of a stressor, as participants in the Stress and Relax groups performed equally. This result is in contrast with previous studies which indicate that false memories increase under stressful conditions. Furthermore, the impact of stress on false memory was not mediated by biological sex, as both male and female participants in the Stress group performed equally. False memory rates increased over a 24- hour retention period in all participants - however the decay of true memory yielded inconsistent results. This was the first study to examine the material specificity of false memory under stressful conditions. It was also the first study to examine whether the amount of false memory errors made under stressful conditions differed between male and female participants. Therefore, the question of whether the material specificity of false memory is affected under stressful conditions and mediated by biological sex remains open for further research. The use of varying false memory paradigms and larger sample populations would help clarify this question.
Includes bibliographical references (leaves 96-114).
Henry, M. 2010. The impact of psychosocial stress and biological sex on false recognition memory. University of Cape Town.