Depression and Cognitive Control across the Lifespan: a Systematic Review and Meta-Analysis

Neuropsychology Review - Depression has been shown to negatively impact neurocognitive functions, particularly those governed by fronto-subcortical networks, such as executive functions. Converging...     

Load effects in attention: Comparing tasks and age groups

Attention is limited in terms of both capacity (i.e., amount of information attended) and selectivity (i.e., the degree to which non-attended information is nonetheless processed). One of the seminal theories in the field, load theory, predicts that these two aspects of attention interact in systematic ways. Specifically, load theory predicts that when the amount of information to attend is less than the available capacity, spare attention will naturally leak out to unattended items. While load theory has found a great deal of empirical support, the robustness of the findings has recently been called into question, in particular with respect to the extent to which the predictions are borne out across different tasks and populations. Here we report tests of perceptual load effects in two different tasks (change detection and enumeration) and in two populations (adults and 7- to 8-year-old children). Adults’ accuracies did not demonstrate the predicted interaction between the capacity and selection dimensions, whereas children’s performance, in addition to being overall worse than adults, did show the interaction. The overall lower accuracy of children was seen to be the result of a larger performance decrement in response to capacity demands, distracting information, and their interaction. Interestingly, while these results were seen at the level of the two tasks, there was no within-participants correlation across tasks. Overall, these results suggest that maturation-related changes attenuate the magnitude of distractor effects in attention, which in turn limits the evidence for interactions between capacity and selection in high-functioning populations.

     

Estimating Gait Stability: Asymmetrical Loading Effects Measured Using Margin of Stability and Local Dynamic Stability

Changes to intersegmental locomotor control patterns may affect body stability. Our study aimed to (a) characterize upper body dynamic stability in response to the unilateral addition of mass to the lower extremity and (b) evaluate the efficacy of 2 different stability measures commonly used in the literature to detect resulting symmetrical step pattern modifications across the weighted segments (spatial) and between epochs of the gait cycle (temporal). Young adults walked on a treadmill while unloaded or with weights applied unilaterally to their foot, shank, or thigh. Both margin of stability and local dynamic stability (LDS) estimates detected similar trends of distal segment weighting resulting in more unstable upper body movement compared to proximal weighting; however only LDS detected anteroposterior changes in upper body stability over time.     

The Development of Sustained Attention in Children: The Effect of Age and Task Load

This study explored how children's sustained attention develops and the effect of manipulating task parameters on sustained attention. The sample comprised 57 children (5–12 years) who completed CogState and Score! (Test of Everyday Attention for Children). Novel variability and traditional indices indicated rapid development from 5–6 to 8–9 years on all measures and a developmental plateau from 8–9 to 11–12, with growth evident on some measures. Findings suggest that sustained attention improves to age 10, then plateaus with only minor improvements. Further, performance was generally poorer on high load tasks compared to low load, with the same developmental pattern uncovered.     

The Impact of the Testing Environment on Affective Changes Following Acute Resistance Exercise

Research has demonstrated the anxiolytic and affective changes following resistance exercise. However, several studies have allowed the participants to leave the testing facility and return at a later time to complete psychological assessments. This weakens internal validity, making it impossible to interpret findings as due to exercise per se. To address this issue, 23 male participants were randomly assigned to either a “stay” or “go” group. Within each group, all participants completed a non-exercise control session and a weight-training session based on 50% of their one repetition maximum for each of five exercises. All participants remained in the laboratory for 60 minutes following each session, at which time only those in the “go” group left the laboratory and returned at 90 and 120 minutes for their remaining affective assessments. The results indicate that despite transient disruptions in mood, an acute bout of resistance exercise results in positive psychological changes that occur within 60 minutes after completion of the exercise session and which persist up to 120 minutes post-exercise. Allowing participants to leave the laboratory or requiring them to remain in the testing environment was found to lead to different patterns of affective responses during the post-exercise assessment period. Future researchers must take into account such methodological issues when designing acute exercise studies requiring extended periods of post-exercise assessment.     

Magnitude comparison revisited: An alternative approach to binary choice under uncertainty

Two generations of psychologists have been interested in understanding binary choice under uncertainty. In the 1970s and 1980s, researchers assumed that people rely on a two-stage magnitude comparison process to make these decisions (Banks, 1977; Moyer & Dumais, 1978). More recently, the focus has shifted to approaches that rely on probabilistic cues and simple heuristics (Gigerenzer & Goldstein, Psychological Review 103, 650-669, 1996). Here, we test competing predictions derived from these two very different approaches and conclude that the magnitude comparison process plays a central role in this task. In support of this conclusion, we present an experiment in which participants were timed as they decided which of two vehicles was more expensive. Pairs composed of one luxury vehicle (e.g., BMW 323i) and one nonluxury vehicle (e.g., Toyota 4Runner) were critical because the magnitude comparison approach correctly predicted that reaction times would decrease with subjective distance, whereas the heuristics approach incorrectly predicted that there would be no relation.     

Emerging roles of epigenetic mechanisms in the enduring effects of early-life stress and experience on learning and memory

Epigenetic mechanisms are involved in programming gene expression throughout development. In addition, they are key contributors to the processes by which early-life experience fine-tunes the expression levels of key neuronal genes, governing learning and memory throughout life. Here we describe the long-lasting, bi-directional effects of early-life experience on learning and memory. We discuss how enriched postnatal experience enduringly augments spatial learning, and how chronic early-life stress results in persistent and progressive deficits in the structure and function of hippocampal neurons. The existing and emerging roles of epigenetic mechanisms in these fundamental neuroplasticity phenomena are illustrated.     

Comparing parent and child perceptions of stigmatizing behavior experienced by children with burn scars

This study examined perceptions of stigmatization in a sample of 85 pediatric burn survivors and their parents. Survivors and a parent independently completed the Perceived Stigmatization Questionnaire (PSQ) rating the frequency that the child experienced three types of stigmatizing behaviors: absence of friendly behavior, confused and staring behavior, and hostile behavior. The sample was divided into a high (top 25%) and low (bottom 75%) perceived stigmatization groups. The mean ratings of parents did not significantly differ from that of children reporting low stigmatization. The mean PSQ parent ratings were significantly lower than those of children reporting high stigmatization. Additionally, the concordance on PSQ subscale scores within child-parent dyads was significantly lower in children reporting high stigmatization relative to child-parent dyads of children reporting low stigmatization. Children surviving burns may experience stigmatization that is under-perceived by their parents. Clinicians should be alert to this potential discrepancy.