Bistable perception in normal aging: perceptual reversibility and its relation to cognition

The effects of age on the ability to resolve perceptual ambiguity are unknown, though it depends on frontoparietal attentional networks known to change with age. We presented the bistable Necker cube to 24 middle-aged and OAs (older adults; 56–78 years) and 20 YAs (younger adults; 18–24 years) under passive-viewing and volitional control conditions: Hold one cube percept and Switch between cube percepts. During passive viewing, OAs had longer dominance durations (time spent on each percept) than YAs. In the Hold condition, OAs were less able than YAs to increase dominance durations. In the Switch condition, OAs and YAs did not differ in performance. Dominance durations in either condition correlated with performance on tests of executive function mediated by the frontal lobes. Eye movements (fixation deviations) did not differ between groups. These results suggest that OAs’ reduced ability to hold a percept may arise from reduced selective attention. The lack of correlation of performance between Hold and executive-function measures suggests at least a partial segregation of underlying mechanisms.     

Quick to the draw: How suspect race and socioeconomic status influences shooting decisions

We examined the role of both suspect race and socioeconomic status (SES) on shooting decisions during a first‐person shooter task. Two studies revealed that both suspect race and SES influenced shooting decisions. Non‐Black participants shot armed high‐SES Black suspects faster than armed high‐SES White suspects and responded “don't shoot” faster for unarmed high‐SES White suspects than unarmed high‐SES Black suspects. No race differences appeared in the low‐SES conditions—responses resembled high‐SES Black suspect. Signal detection, misses, and false alarm analyses revealed participants erred toward not shooting high‐SES White suspects. The current studies draw attention to considering both race and SES during shooting decisions.     

Addressing the “Replication Crisis”: Using Original Studies to Design Replication Studies with Appropriate Statistical Power

Psychology is undergoing a replication crisis. The discussion surrounding this crisis has centered on mistrust of previous findings. Researchers planning replication studies often use the original study sample effect size as the basis for sample size planning. However, this strategy ignores uncertainty and publication bias in estimated effect sizes, resulting in overly optimistic calculations. A psychologist who intends to obtain power of .80 in the replication study, and performs calculations accordingly, may have an actual power lower than .80. We performed simulations to reveal the magnitude of the difference between actual and intended power based on common sample size planning strategies and assessed the performance of methods that aim to correct for effect size uncertainty and/or bias. Our results imply that even if original studies reflect actual phenomena and were conducted in the absence of questionable research practices, popular approaches to designing replication studies may result in a low success rate, especially if the original study is underpowered. Methods correcting for bias and/or uncertainty generally had higher actual power, but were not a panacea for an underpowered original study. Thus, it becomes imperative that 1) original studies are adequately powered and 2) replication studies are designed with methods that are more likely to yield the intended level of power.     

Emigration and community

In this paper I consider Gillian Brock’s and Michael Blake’s discussion of emigration in Debating Brain Drain in relation to the particular case of South Africa, and explore whether skilled white people have a duty to remain in the country. Focusing on the role of community in this debate, I argue that communities and allegiances in South Africa are still too divided and antagonistic for them to play the duty-grounding role that Brock requires.     

Adjustment modes in the trajectory of progressive multiple sclerosis: a qualitative study and conceptual model

Objective: We examined cognitive and behavioural challenges and adaptations for people with progressive multiple sclerosis (MS) and developed a preliminary conceptual model of changes in adjustment over time.

Design: Using theoretical sampling, 34 semi-structured interviews were conducted with people with MS. Participants were between 41 and 77 years of age. Thirteen were diagnosed with primary progressive MS and 21 with secondary progressive MS. Data were analysed using a grounded theory approach.

Results: Participants described initially bracketing the illness off and carrying on their usual activities but this became problematic as the condition progressed and they employed different adjustment modes to cope with increased disabilities. Some scaled back their activities to live a more comfortable life, others identified new activities or adapted old ones, whereas at times, people disengaged from the adjustment process altogether and resigned to their condition. Relationships with partners, emotional reactions, environment and perception of the environment influenced adjustment, while people were often flexible and shifted among modes.

Conclusions: Adjusting to a progressive condition is a fluid process. Future interventions can be tailored to address modifiable factors at different stages of the condition and may involve addressing emotional reactions concealing/revealing the condition and perceptions of the environment.     

To what degree do situational influences explain spontaneous helping behaviour? A meta-analysis

Prosocial behaviour is an interdisciplinary topic, involving psychologists, philosophers, and educators. Based on experimental helping research, some moral philosophers have claimed that helping behaviour is entirely situationally determined. The dominance of situational factor experimentation gives the appearance that situational factors alone can explain helping behaviour. This meta-analysis investigated situational explanations of helping behaviour with 286 effects and 46,705 participants from experimental studies with non-manipulation control groups, and observed unilateral adult behavioural helping. Results indicated expected group differences in helping behaviour frequency among help encouraging or help discouraging experimental conditions and no-manipulation control conditions. Helping behaviour was also frequent in help discouraging and control conditions and far from universal in help encouraging conditions. Because helping occurred in control groups, situational factors cannot explain all observed helping. Because helping was not universal in help encouraging conditions, it raises the question of individual differences in responsiveness to helping cues.     

Anvil or Onion? Determinism as a Layered Concept

Kellert (In the Wake of Chars, University of Chicago press, Chicago, 1993) has argued that Laplacean determinism in classical physics is actually a layered concept, where various properties or layers composing this form of determinism can be peeled away. Here, I argue that a layered conception of determinism is inappropriate and that we should think in terms of different deterministic models applicable to different kinds of systems. The upshot of this analysis is that the notion of state is more closely tied to the kind of system being investigated than is usually considered in discussions of determinism. So when investigating determinism corresponding changes to the appropriate notion of state – and, perhaps, the state space itself – also need to be considered.