Adaptive Memory: Fitness Relevance and the Hunter-Gatherer Mind

ABSTRACT— Recent studies suggest that human memory systems are "tuned" to remember information that is processed in terms of its fitness value. When people are asked to rate the relevance of words to a survival scenario, performance on subsequent surprise memory tests exceeds that obtained after most other known encoding techniques. The present experiments explored this effect using survival scenarios designed to mimic the division of labor thought to characterize early hunter-gatherer societies. It has been suggested that males and females have different cognitive specializations due to the unique survival tasks (hunting and gathering, respectively) they typically performed during periods of human evolution; the present experiments tested whether such specializations might be apparent in memory for words rated for relevance to these activities. Males and females were asked to rate the relevance of random words to prototypical hunting and gathering scenarios or to matched, non-fitness-relevant control scenarios (gathering food on a scavenger hunt or in a hunting contest). Surprise retention tests revealed superior memory for the words when they were rated for relevance to hunting and gathering scenarios, compared with when they were rated for relevance to the control scenarios, but no sex differences were found in memory performance.     

Enhanced feminine sexual behavior and infertility in female rats prenatally treated with an antiestrogen

An attempt to elucidate the possible role of prenatal estrogen on the development of feminine sexual behavior and reproductive function was made by treating females with the antiestrogen CI628 prenatally on days 13-19. Control females were prenatally treated with saline or remained untreated. The animals were delivered by caesarian section on day 22 of pregnancy and placed with foster mothers whose newborn pups had been previously removed. Intact peripubertal females in each treatment group were observed for several reproductive measures, including the capacity to become pregnant. Other females were ovariectomized in adulthood and treated with estradiol benzoate (EB) (1, 1.5, 2 or 4 micro g/rat) and 0.5 mg progesterone and tested for receptivity, proceptivity and sexual partner preference. Two weeks after the completion of these tests, the females were injected daily for 7 days with 0.25 mg testosterone and tested for sexual partner preference and mounting behavior. The results obtained showed accelerated vaginal opening, and infertility in the antiestrogen-treated intact females and enhanced receptivity and proceptivity in response to 1 micro g EB in the antiestrogen ovariectomized females. Sexual partner preference and mounting behavior did not differ between groups. These results suggest an involvement of prenatal estrogen on the development of female reproductive function, but not on behavioral differentiation.     

The influence of the visual surrounding environment in older adults and young adults’ cognitive performance: an alternative paradigm

ABSTRACT

This study investigated how the characteristics of the visual surrounding environment influence older- and young-adults’ cognitive performance. Sixty-four older adults and 64 young adults performed four visual cognitive tasks (attention and memory tasks) in two independent sessions while being exposed to a high-load and a low-load visual surrounding environment. We expected that the high-load environment would hurt the older-adults performance due to typical difficulties in ignoring irrelevant stimuli, whereas no such effect would likely occur for the young-adults whose cognitive abilities are at their best. Overall, our results were consistent with our prediction in three tasks (go/no-go, choice reaction time, and Corsi block-tapping). Additionally, the older adults performed worse than the young adults in all tasks, thus confirming expected age-related differences. Our results are consistent with those obtained when distractors and targets are presented in the same display, now using a paradigm which locates the distractors in the surrounding environment.