Newcomer et al. (1999)

Preperation for SAQ Hormones

aim

investigate whether high levels of cortisol interfere with verbal declarative memory

cortisol

stress hormone; receptor sites on hippocampus (responsible for STM-LTm transfer)

sample

employess and students at Washington university medical center

exclusion criteria

pregnant, history of mental illness, head trauma, or corticosteroid treatment

research design

double blind labratory experiment

condition 1 (high cortisol)

160mg cortisol/day for 4 days (major stress levels)

matching

participants matched by age and gender across conditions

condition 2 (low cortisol)

40mg cortisol/day for 4 days (minor stress levels)

condition 3 (placebo)

placebo tablets; no active ingredient

task

listen to and recall prose passapges of equal difficulty

testing times

baseline before pill, day 1, day 4, and day 6 to check for long-term effects

counterbalancing

different prose texts used across days; balanced to control difficulty

baseline

no significant group differenxes before treatment (controlled for individual differences)

high cortisol

worst perfomance in recalling prose (impaired verbal declarative memory)

low cortisol

slight improvement in recall compared to placebo

reversability

high cortisol group returned to normal after stopping treatment

conclusion

high cortisol interferes with recall; moderate cortisol may aid memory

strength; cause-and-effect

experimental design allowed clear link between cortisol elvels and memory

strength: baseline test

controlled for individual memory differences

strength; counterbalancing texts

contolled for differences in prose difficulty

limitation: limited control

participants not in lab full-time; possible extraneous stressors

limitation: ecological validtiy

prose recall not an authentic memory task (limited generalisability)

ethics

cortisol impaired memory temporarily; informed consent given and no permanent harm