A male advantage for spatial and object but not verbal working memory using the n-back task.

Sex-related differences have been reported for performance and neural substrates on some working memory measures that carry a high cognitive load, including the popular n-back neuroimaging paradigm. Despite some evidence of a sex effect on the task, the influence of sex on performance represents a potential confound in neuroimaging research. The present study investigated sex-related differences in verbal, spatial, and common object versions of the high cognitive load "n-back" working memory task. Eighteen male and 18 female undergraduates completed all 3 versions of the task. A mixed ANOVA, with Sex (male and female) as the between-subjects factor and Condition (verbal, spatial, and object) as the within-subjects repeated measure revealed that males were significantly more accurate than females on the spatial and object versions of the n-back task and performed equivalently to females on the verbal version of the task. Although the expected female advantage for verbal working memory was not found using this effortful n-back task, these results support a male advantage for high cognitive load spatial and object working memory. Future research should take into account the influence of sex on performance of the n-back task, and examine sex-related differences in working memory using other paradigms.

Endocrine therapy is associated with low performance on some estrogen-sensitive cognitive tasks in postmenopausal women with breast cancer.

This study investigated the effects of endocrine therapy (i.e., tamoxifen and anastrozole) on cognitive functioning by comparing 28 postmenopausal women with breast cancer to 37 healthy age-equivalent controls. Participants completed neuropsychological tests previously shown to be estrogen sensitive (e.g., verbal memory, letter fluency). A significant treatment effect was observed on speeded measures of letter fluency, complex visuomotor attention, and manual dexterity, but not on measures of verbal or object-location memory, or on tests presumed to be estrogen insensitive (e.g., spatial ability). In partial support of previous research, these results indicate that endocrine therapy can have detrimental effects on speeded higher brain functions but not necessarily on memory.

The female advantage in object location memory is robust to verbalizability and mode of presentation of test stimuli.

This study extends Duff and Hampson's [Duff, S., & Hampson, E. (2001). A sex difference on a novel spatial working memory task in humans. Brain and Cognition,47, 470-493] finding of a sex-related difference in favor of females for an object location memory task. Twenty female and 20 male undergraduate students performed both manual and computer-generated versions of the task using stimuli that varied in degree of verbalizability. A 2x2x3 ANOVA with Sex as a between-subjects factor, and Presentation (manual or computer) and Stimuli (common objects, common shapes, and novel shapes) as within-subjects repeated measures revealed a significant main effect for Sex. Females made fewer errors than males regardless of presentation and across the three levels of verbalizability (i.e., stimulus types); moreover, the effect size was considered "large" [Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Berlin: Springer]. These findings are interpreted within the context of the current literature that demonstrates a female advantage for object location memory (e.g., [Voyer, D., Postma, A., Brake, B., & Imperato-McGinley, J. (2007). Gender differences in object location memory: A meta-analysis. Psychonomic Bulletin and Review, 14, 23-38]).

Hemispheric asymmetries for gap detection depend on noise type.

Studies of temporal processing asymmetries in the auditory modality have not produced consistent results. Some investigators have found a left hemisphere advantage, but others have failed to replicate this result. The present experiment investigated the possibility that differing properties of the noise employed between these experiments could be responsible for the conflicting results. Short bursts (300 ms) of white or brown noise were delivered monaurally to 42 participants. Half of the stimuli contained 3-5 ms gaps of silence. A right ear (left hemisphere) advantage in accuracy was observed in the white noise condition, but there was no such difference in the brown noise condition. This result demonstrates that the different acoustic properties of the stimuli between experiments can account for some of the discrepancies in their findings, and supports the position that the left hemisphere is superior at processing rapid temporal changes.