Episodic feeling-of-knowing accuracy and cued recall in the elderly: evidence for double dissociation involving executive functioning and processing speed

This research investigated adult age differences in a metamemory monitoring task-episodic feeling-of-knowing (FOK) and in an episodic memory task-cued recall. Executive functioning and processing speed were examined as mediators of these age differences. Young and elderly adults were administered an episodic FOK task, a cued recall task, executive tests and speed tests. Age-related decline was observed on all the measures. Correlation analyses revealed a pattern of double dissociation which indicates a specific relationship between executive score and FOK accuracy, and between speed score and cued recall. When executive functioning and processing speed were evaluated concurrently on FOK and cued recall variables, hierarchical regression analyses showed that executive score was a better mediator of age-related variance in FOK, and that speed score was the better mediator of age-related variance in cued recall.     

Gender and Diversity in Organizations: Past,Present, and Future Directions

This introduction reviews some of the key issues that have been studied by researchers focused on gender and diversity in organizations. Issues such as discrimination, affirmative action, barriers to career advancement, and sexual harassment at work are discussed. Although the study of gender and diversity in organizations has expanded in the last decade, key areas of research are still underrepresented. Issues for future research in this area are discussed.     

Discrimination reversal conditioning of an eyeblink response is impaired by NMDA receptor blockade

In the present study we examined the effects of the specific NMDA receptor antagonist CPP on discrimination reversal learning in rabbits. We report two primary findings. First, the institution of NMDA receptor blockade had no effect on a learned discrimination. Second, after stimulus reversal, CPP treatment impaired acquisition of the discrimination reversal. This impairment manifested itself early in training as a retardation in acquisition of a CR to the new CS+ and late in training as an inability to suppress responsiveness to the new CS-. Given the comparability of the present results with previously published results for phenytoin-treated rabbits, we suggest that the effects of phenytoin on learning in this paradigm is at least in part mediated by its effects on NMDA receptors. We further suggest that these findings emphasize the need to better define the role of NMDA receptor activation and hippocampally-mediated circuits in a variety of associative learning paradigms.     

A Psychometric Evaluation of the Approach and Avoidance of Alcohol Questionnaire (AAAQ) in Alcohol Dependent Outpatients

The Approach and Avoidance of Alcohol Questionnaire (AAAQ; McEvoy et al. in Addiction 99:482–497, 2004) was administered to a clinical sample of 138 alcohol dependent men and women. An exploratory factor analysis was used to determine the AAAQ factor structure and a confirmatory analysis run on a second administration of the AAAQ. Convergent validity was examined by conducting an alcohol cue reactivity test and by administering the Timeline Follow-Back (TLFB), a retrospective calendar method for assessing alcohol consumption, and several measures of alcohol-related problems. The factor analysis supported a two-factor solution representing approach and avoidance dimensions. Regressions predicting measures of alcohol cue reactivity, alcohol consumption, and other alcohol-related constructs with the AAAQ provide support for its convergent validity. The results suggest that alcohol craving may be viewed as a multi-dimensional construct that includes both approach and avoidance inclinations which may vary depending on the population under examination.

Comparative risk and perceived control: implications for psychological and physical well-being among older adults

As older adults become more susceptible to certain health crises, their preoccupation with their risk of suffering such events increases. Understanding the implications of risk perceptions is critical because they may have consequences for psychological and physical well-being in later life. In the present study of older adults living in the community, the authors examined participants' comparative risk estimates (CREs)--their perceptions of their own risk relative to a similar other's risk--of suffering a hip fracture. Using multiple regression analyses, the authors examined the role of CREs on psychological well-being (negative emotions, life satisfaction) and self-rated physical well-being (general physical health, recent physical health). The authors expected perceived control (PC) to moderate the relationship between CREs and well-being. The predicted interaction did occur: Among individuals with high PC, comparative optimism (perceiving a comparatively low risk) was associated with better psychological well-being (fewer negative emotions and greater life satisfaction) and better physical well-being (general and recent physical health) relative to comparative pessimism (perceiving a comparatively high risk). Among individuals with low PC, there were no differences in well-being between comparative optimists and comparative pessimists. These findings suggest that the protective effect of comparative optimism on well-being is limited to older adults who have a strong sense of control.     

Infants’ Brain Responses to Looming Danger: Degeneracy of Neural Connectivity Patterns

Abstract

A fundamental property of most animals is the ability to see whether an object is approaching on a direct collision course and, if so, when it will collide. Using high-density electroencephalography in infants and a looming stimulus approaching under three different accelerations, we previously found how visual information for impending collision is sustained in the young human nervous system. In the present study, using longitudinal data on 25 infants at 4–5?months and 12–13?months, we show that infants’ looming-related brain activity is clearly localized in the visual cortex (V1) following retinotopic mapping, but is highly adaptive in its organization otherwise. Analyzing the orientation of electrical source flow, we provide evidence for a high degree of variability, spread across a relatively large area of the visual cortex. The findings reveal a highly dynamic functional organization, with connectivity patterns constantly emerging and changing in many different directions between trials. This suggests degeneracy of neural connectivity patterns through reentry principles, where neurons temporarily assemble to enable an appropriate looming response with the necessary precision.     

When less is more: like humans,chimpanzees (Pan troglodytes) misperceive food amounts based on plate size

We investigated whether chimpanzees (Pan troglodytes) misperceived food portion sizes depending upon the context in which they were presented, something that often affects how much humans serve themselves and subsequently consume. Chimpanzees judged same-sized and smaller food portions to be larger in amount when presented on a small plate compared to an equal or larger food portion presented on a large plate and did so despite clearly being able to tell the difference in portions when plate size was identical. These results are consistent with data from the human literature in which people misperceive food portion sizes as a function of plate size. This misperception is attributed to the Delboeuf illusion which occurs when the size of a central item is misperceived on the basis of its surrounding context. These results demonstrate a cross-species shared visual misperception of portion size that affects choice behavior, here in a nonhuman species for which there is little experience with tests that involve choosing between food amounts on dinnerware. The biases resulting in this form of misperception of food portions appear to have a deep-rooted evolutionary history which we share with, at minimum, our closest living nonhuman relative, the chimpanzee.     

Do rhesus monkeys (Macaca mulatta) perceive the Zöllner illusion?

A long-standing debate surrounds the issue of whether human and nonhuman animals share the same perceptual mechanisms. In humans, the Zöllner illusion occurs when two parallel lines appear to be convergent when oblique crosshatching lines are superimposed. Although one baboon study suggests that they too might perceive this illusion, the results of that study were unclear, whereas two recent studies suggest that birds see this illusion in the opposite direction from humans. It is currently unclear whether these mixed results are an artifact of the experimental design or reflect a peculiarity of birds’ visual system or, instead, a wider phenomenon shared among nonhuman mammals. Here, we trained 6 monkeys to select the narrower of two gaps at the end of two convergent lines. Three different conditions were set up: control (no crosshatches), perpendicular (crosshatches not inducing the illusion), and Zöllner (crosshatches inducing the illusion in humans). During training, the degrees of convergence between the two lines ranged from 15° to 12°. Monkeys that reached the training criterion were tested with more difficult discriminations (11°–1°), including probe trials with parallel lines (0°). The results showed that monkeys perceived the Zöllner illusion in the same direction as humans. Comparison of these data with the data from bird studies points toward the existence of different orientation-tuned mechanisms between primate and nonprimate species.