Post-event review in older and younger adults: improving memory accessibility of complex everyday events.

Recalling an event at 1 time often increases the likelihood that it will be remembered at a still later time. The authors examined the degree to which older and younger adults' memory for everyday events that they watched on a videotape was improved by later seeing photographs or reading brief verbal descriptions of those events. Both older and younger adults recalled more events, in greater detail, with than without review. Verbal descriptions enhanced later recall to the same degree as reviewing photographs. Younger adults generally gained more from review than older adults on measures of the absolute number of details recalled and when facilitation was assessed relative to a no-review control condition, but not when memory for reviewed events was expressed as a proportion of each individual's total recall. Post-event review has clear potential practical benefits for improving memory of older adults.

Development of depression from preadolescence to young adulthood: emerging gender differences in a 10-year longitudinal study.

The authors investigated the emergence of gender differences in clinical depression and the overall development of depression from preadolescence to young adulthood among members of a complete birth cohort using a prospective longitudinal approach with structured diagnostic interviews administered 5 times over the course of 10 years. Small gender differences in depression (females greater than males) first began to emerge between the ages of 13 and 15. However, the greatest increase in this gender difference occurred between ages 15 and 18. Depression rates and accompanying gender differences for a university student subsample were no different than for a nonuniversity subsample. There was no gender difference for depression recurrence or for depression symptom severity. The peak increase in both overall rates of depression and new cases of depression occurred between the ages of 15 and 18. Results suggest that middle-to-late adolescence (ages 15-18) may be a critical time for studying vulnerability to depression because of the higher depression rates and the greater risk for depression onset and dramatic increase in gender differences in depression during this period.

False recollection induced by photographs: a comparison of older and younger adults.

Looking at photographs constitutes an important everyday memory activity for older adults. The authors found that reviewing photographs of events seen earlier in a videotape increases the likelihood that both older and younger adults remember specific details from the reviewed event (W. Koutstaal, D. L. Schacter, M. K. Johnson, K. E. Angell, & M. S. Gross, 1977). In the present study, the authors report 2 experiments demonstrating that photo review can also produce false recollection in elderly adults: After reviewing photos of events that had not been shown earlier in a videotape, older but not younger adults were later more likely to "remember" that those events had been shown in the videotape. False recollection induced by photo review appears to reflect an age-related deficit in source-monitoring abilities.

Effects of trimethyltin on repeated acquisition (learning) in the radial-arm maze.

Trimethyltin (TMT) was used as a positive control neurotoxicant to evaluate a repeated acquisition procedure for the 8-arm radial maze. Ten male Long-Evans rats were trained to collect a single food pellet at the end of each baited arm on each trial of a daily 12-trial test session. Four of the eight arms were baited on all trials of a given session. The set of four baited arms was changed each day: thus the rats were required to learn a new set of baited arms in each session. In trained rats, error frequencies (entries into unbaited arms) declined from about 4 on Trial 1 to less than 1 on Trials 4-12 in each session: this within-session error reduction thus defined an acquisition baseline which was evaluated for its sensitivity to TMT. Learning was impaired after 7 mg/kg (iv) TMT, as shown by a slower decline in within-session error frequencies in all treated rats. Errors and response times were elevated for 5 weeks after TMT but returned to control levels thereafter. Histological examination of hippocampi showed damage in all treated rats 18 weeks after treatment; however, no significant relationship between degree of damage and behavioral effect was observed. Analysis of errors showed that TMT more strongly impaired the rats' ability to avoid arms in the current unbaited set than those baited arms already entered on a given trial (i.e., working memory). These dissociations between behavior and hippocampal morphology in terms of time course, magnitude of effect across animals, and error type suggest that performance of this task does not depend upon hippocampal integrity, as do other tasks involving spatial working memory. Recovery of function in this kind of task may shed light on processes of neural plasticity after exposure to neurotoxic compounds.