Prenatal maternal cortisol measures predict learning and short-term memory performance in 3- but not 5-month-old infants.

Little is known about relations between maternal prenatal stress and specific cognitive processes-learning and memory-in infants. A modified crib-mobile task was employed in a longitudinal design to test relations between maternal prenatal cortisol, prenatal subjective stress and anxiety, psychosocial variables, and learning and memory in 3- and 5-month-old infants. Results revealed that maternal prenatal cortisol was affected by particular psychosocial variables (e.g., maternal age, whether or not the infant's grandmother provided childcare, financial status), but was unrelated to measures of maternal depression, anxiety, and stress. Although maternal prenatal cortisol was not predictive of learning or memory performance in 5-month-old infants, higher levels of basal maternal cortisol and reduced prenatal cortisol response was predictive of some learning and short-term memory measures in 3-month-old infants. These results suggest an influence of maternal neuroendocrine functioning on fetal neurological development, and the importance of separate examination of subjective and biological measures of stress.

Self-regulation and working memory in musical performers.

Performing music in front of others can be stressful, even for experienced performers. The physiological effects of stress, namely, increases in cortisol and sympathetic nervous system activity, have been shown to have detrimental effects on cognition, particularly working memory. This study used an audition-like performance scenario to elicit a stress response in performers who differed in their degree of musical experience. We expected that participants with more musical experience would be better able to regulate their stress response, would report lower levels of anxiety, insecurity, and nervousness, and would show better working memory following the stressor, compared to participants with less musical experience. Although we did not find differences between more and less experienced performers in their sympathetic nervous system activity or their self-reported feelings of anxiety and nervousness, we did find some important differences: following the stressor, more experienced performers were less insecure, they showed better regulation of their cortisol response, and they demonstrated better working memory.

Retrospective and prospective metacognitive judgments in rhesus macaques (Macaca mulatta).

A growing body of research suggests that some non-human animals are capable of making accurate metacognitive judgments. In previous studies, non-human animals have made either retrospective or prospective judgments (about how they did on a test or how they will do on a test, respectively). These two types of judgments are dissociable in humans. The current study tested the abilities of two rhesus macaque monkeys to make both retrospective and prospective judgments about their performance on the same memory task. Both monkeys had been trained previously to make retrospective confidence judgments. Both monkeys successfully demonstrated transfer of retrospective metacognitive judgments to the new memory task. Furthermore, both monkeys transferred their retrospective judgments to the prospective task (one, immediately, and one, following the elimination of a response bias). This study is the first to demonstrate both retrospective and prospective monitoring abilities in the same monkeys and on the same task, suggesting a greater level of flexibility in animals' metacognitive monitoring abilities than has been reported previously.

Does visual information influence infants' movement to music?

Humans are often exposed to music beginning at birth (or even before birth), yet the study of the development of musical abilities during infancy has only recently gained momentum. The goals of the present study were to determine whether young infants (ages four to seven months) spontaneously moved rhythmically in the presence of music, and whether the presence of visual information in addition to music would increase or decrease infants' movement. While nearly all infants moved in the presence of music, very few infants demonstrated rhythmic movement. Results revealed that, when visual information was present, and particularly when infants appeared to show focused attention toward the visual information, infants moved less than when only auditory information was present. The latter result is in agreement with most studies of sensory dominance in adults in which visual stimuli are dominant over auditory stimuli.

Increases in cortisol are positively associated with gains in encoding and maintenance working memory performance in young men.

Past studies have demonstrated that increases in cortisol secretion are associated with either enhancements or impairments of long-term memory, depending on the subprocess involved. However, working memory is generally studied as a unified system within the cortisol literature. The present study sought to determine if cortisol increases are positively associated with increases in performance in the encoding subprocess of working memory, and whether increases are positively or negatively associated with performance changes in the maintenance subprocess. Thirty-three young men (M = 19.4 years, SD = 0.89) participated in a change-detection task, consisting of a condition requiring encoding only and a condition requiring both encoding and maintenance. To elicit a cortisol response, participants completed the Trier Social Stress Test (TSST) between two administrations of the task. Cardiovascular measurements and saliva samples were obtained before the TSST (T1), and mid-way between blocks of the second administration of the change-detection task (T2), to measure autonomic and cortisol responses to the TSST evident during the second change-detection task. Cortisol increases between T1 and T2 were positively correlated with both encoding (r(32) = 0.503, p = 0.003) and maintenance (r(32) = 0.463, p = 0.007) performance. This is a novel finding as previous studies have shown an impairing effect of cortisol on working memory. The positive relation between cortisol and working memory has likely been obscured in previous tasks, which did not examine these specific subprocesses in isolation from each other. The beneficial role of cortisol in the stress response is discussed.

Sequential planning in rhesus monkeys (Macaca mulatta).

In the current study, we examined the planning abilities of rhesus monkeys (Macaca mulatta) by training them on a five-item list composed of coloured photographs and then testing them on switch and mask trials. In contrast to previous studies where monkeys made responses using a joystick, in the current study, monkeys made responses directly to a touch screen. On switch trials, after a response to the first list item, the on-screen positions of two list items were exchanged. Performance on trials in which the second and third list items were exchanged was poorer compared to normal (non-switch) trials for all subjects. When the third and fourth items were exchanged, however, only one subject continued to show performance deficits. On mask trials, following a response to the first item, the remaining items were covered by opaque white squares. When two items were masked, all four subjects responded to each masked item at a level significantly above chance. When three items were masked, however, only one subjected was able to respond to all three masked items at a level significantly above chance. The results of the present study indicate that three of our four monkeys planned one response ahead while a single monkey planned two responses ahead. The significance of these findings is discussed in relation to previous studies on planning in chimpanzees and monkeys.