Research suggests that stress can trigger high levels of cortisol, which can in turn lead to memory deficits.  This is because cortisol has been found to inhibit the uptake of glucose in hippocampal cells, thereby resulting in a loss of their energy source and contributing to early hippocampal cell death (McEwen & Sapolosky, 1995).  The hippocampus has been shown to be involved in a variety of memory processes including object-location memory (Owen & Milner, 1996).  Examined in this study was whether laboratory induced stress would contribute to higher cortisol levels and poorer object-location memory scores.  A total of 13 participants completed the study with 6 randomly assigned to the stress condition (i.e., noise and a demanding cognitive task), and the remaining 7 assigned to the non-stress condition (i.e., reading a magazine).  Five cortisol levels and two object-location memory scores were recorded from each participant.  It was predicted that participants in the stress condition would show higher cortisol levels and lower object-location memory scores compared to participants in the non-stress condition.  In addition, it was expected that higher cortisol levels will be correlated with lower object-location memory scores in participants in the stress condition only.  Comparisons between the control and experimental group showed no significant differences in cortisol levels or object-location memory scores, which does not support the hypotheses set forth.  However, relationships were found in the experimental group between an increase in wrong hits and a decrease in cortisol level, whereas a decrease in cortisol level for the control group was positively correlated with the number of right hits in the object-location memory test.  Reasons for the observed results are discussed in terms of the inverted-U relationship between cortisol and memory performance as well as hypothalamic-pituitary-adreno cortical axis (HPA) and sympathetic-adrenal medullary system (SAM) activation.  Individual cases are discussed in terms of specific patterns of cortisol secretion following the object-location memory test.  Explanations such as stress inoculation and coping strategies are explored.  The findings demonstrate why it is important to examine individual cases and take into consideration individual differences.  Implications of this study are that in female college students, the perception of a stressor and mediating factors such as coping style can mediate the cortisol response.  Memory performance is thereby effected by these individual differences.
 
 

click here to return to main page

(to Introduction)