A framework for Bayesian optimality of psychophysical laws

The Weber–Fechner law states that perceived intensity is proportional to physical stimuli on a logarithmic scale. In this work, we formulate a Bayesian framework for the scaling of perception and find logarithmic and related scalings are optimal under expected relative error fidelity. Therefore, the Weber–Fechner law arises as being information theoretically efficient under the constraint of limited representability. An even stronger connection is drawn between the Weber–Fechner law and a Bayesian framework when neural storage or communication is the dominant concern, such as for numerosity. Theoretical results and experimental verification for perception of sound intensity are both presented.     

Testing conclusions from functional imaging of working memory with data from acute stroke

Functional imaging studies indicate that the left hemisphere mediates verbal working memory, while the right hemisphere mediates both verbal and spatial working memory. We evaluated acute stroke patients with working memory tests and imaging to identify whether unilateral dysfunction causes deficits in spatial and/or verbal working memory deficits. While left cortical stroke patients had verbal working memory impairments (p<0.003), right cortical stroke patients had both verbal p<0.007) and spatial working memory (p<0.03) impairments, confirming functional imaging results. Patients with transient ischemic stroke and patients with non-cortical stroke did not have significant deficits in working memory in either modality.     

A study of time management: the correlation between video game usage and academic performance markers.

This study analyzes the correlation between video game usage and academic performance. Scholastic Aptitude Test (SAT) and grade-point average (GPA) scores were used to gauge academic performance. The amount of time a student spends playing video games has a negative correlation with students' GPA and SAT scores. As video game usage increases, GPA and SAT scores decrease. A chi-squared analysis found a p value for video game usage and GPA was greater than a 95% confidence level (0.005 < p < 0.01). This finding suggests that dependence exists. SAT score and video game usage also returned a p value that was significant (0.01 < p < 0.05). Chi-squared results were not significant when comparing time spent studying and an individual's SAT score. This research suggests that video games may have a detrimental effect on an individual's GPA and possibly on SAT scores. Although these results show statistical dependence, proving cause and effect remains difficult, since SAT scores represent a single test on a given day. The effects of video games maybe be cumulative; however, drawing a conclusion is difficult because SAT scores represent a measure of general knowledge. GPA versus video games is more reliable because both involve a continuous measurement of engaged activity and performance. The connection remains difficult because of the complex nature of student life and academic performance. Also, video game usage may simply be a function of specific personality types and characteristics.     

When less is more and when more is more: The mediating roles of capacity and speed in brain-behavior efficiency

An enduring enterprise of experimental psychology has been to account for individual differences in human performance. Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individual differences but this burgeoning literature has been characterized by inconsistent results. We argue that careful design and analysis of neuroimaging studies is required to separate individual differences in processing capacity from individual differences in processing speed to account for these differences in the literature. We utilized task designs which permitted separation of processing capacity influences on brain-behavior relationships from those related to processing speed. In one set of studies, participants performed verbal delayed-recognition tasks during blocked and event-related fMRI scanning. The results indicated that those participants with greater working memory (WM) capacity showed greater prefrontal cortical activity, strategically capitalized on the additional processing time available in the delay period, and evinced faster WM-retrieval rates than low-capacity participants. In another study, participants performed a digit-symbol substitution task (DSST) designed to minimize WM storage capacity requirements and maximize processing speed requirements during fMRI scanning. In some prefrontal cortical (PFC) brain regions, participants with faster processing speed showed less PFC activity than slower performers while in other PFC and parietal regions they showed greater activity. Regional-causality analysis indicated that PFC exerted more influence over other brain regions for slower than for faster individuals. These results support a model of neural efficiency in which individuals differ in the extent of direct processing links between neural nodes. One benefit of direct processing links may be a surplus of resources that maximize available capacity permitting fast and accurate performance.     

What Makes for a Good Life? A Four-Nation Study

How do we assess the value of our lives? What makes the life we live a good or worthy one in our own eyes? What are its aims? The answers to these questions are implicit in the often unarticulated commitments by which people define their selves, purposes, and actions. These commitments structure the moral framework that guides our everyday qualitative distinctions and positions us within a unified narrative of continuity and change. The substantive conception of a good life, we argue, presupposes but is not reducible to a set of basic values. As an initial exploration of cultural variation, Canadian, Chinese, Indian, and Japanese university students were compared on what they held to be most important for assessing the worth of their lives. The results revealed considerable commonality of content with notable differences consistent with the cultural ethos of each group.     

Eschewing Community: Black Metal

There is a great deal of literature that examines community orientations, in particular consumption‐based subcultures rooted in the appreciation of music scenes such as heavy metal and its subgenres. Much of this literature focuses on aspects of community maintenance, reaffirmation of shared identities and building of social bonds. In the present article, we report a study in which consumption of, and fandom in a specific scene in extreme metal, namely black metal, may lead to very unique consumer cultural orientations. Our analyses reveal that black metal fans' identities reside in a realm outside of a desired collective identification and tightly knit community, but rather one that uses signification, or representational means to convey meaning and belonging, as a way to signal repugnance with society and a reverence of individuality. The study engages a mixed qualitative approach utilizing interviews, observational research and content analysis to demonstrate how self‐identity related to the black metal music scene can thrive through an ideological and semiotic rejection of traditional community orientations seen in the majority of other extreme metal music scenes. This paper challenges traditional conceptualizations of group identity in music scenes by closely examining aspects of signification and fandom in black metal that represent a unique system of shared identities devoid of community building. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of norms for executive functions in typically-developing Indian urban preschool children and its association with nutritional status

Executive functions (EFs) are essential and important for achieving success in children’s everyday lives and play a fundamental role in children’s cognitive, academic, social, emotional and behavioral functioning. A cross-sectional study was carried out to develop age- and sex-specific norms for EFs using the Behavior Rating Inventory of Executive Function – Preschool Version (BRIEF-P) among 2- to 5-year-olds from urban Bangalore, India. In addition, the association between EFs and anthropometric measures, a marker of nutritional status, is also examined. Primary caregivers of 412 children, equally distributed by age and sex, participated. Raw scores for each domain and indices were converted to standard t-scores and percentiles were computed. A t-score at or above 63 corresponding to the 90th percentile was considered as the cutoff for executive dysfunction in this sample. The prevalence of executive dysfunction is 10% based on the Global Executive Composite score of the BRIEF-P. The cutoff score for identifying executive dysfunction using existing United States (US) norms is higher compared to the cutoff score obtained in the current study. Therefore, using US norms for Indian children could result in the prevalence of executive dysfunction been underestimated. Multiple linear regression analysis revealed that stunted and underweight children have significantly elevated EF scores after adjusting for age, sex and socioeconomic status (SES; p < .01). A greater understanding of EFs in preschool children is important for the early identification of executive dysfunction and implementing interventions to improve their future prospects. This study also shows that undernourished children are more likely to have executive dysfunction.     

Validating age-related functional imaging changes in verbal working memory with acute stroke

Functional imaging studies consistently find that older adults recruit bilateral brain regions in cognitive tasks that are strongly lateralized in younger adults, a characterization known as the Hemispheric Asymmetry Reduction in Older Adults model. While functional imaging displays what brain areas are active during tasks, it cannot demonstrate what brain regions are necessary for task performance. We used behavioral data from acute stroke patients to test the hypothesis that older adults need both hemispheres for a verbal working memory task that is predominantly left-lateralized in younger adults. Right-handed younger (age ? 50, n = 7) and older adults (age > 50, n =21) with acute unilateral stroke, as well as younger (n =6) and older (n =13) transient ischemic attack (TIA) patients, performed a self-paced verbal item-recognition task. Older patients with stroke to either hemisphere had a higher frequency of deficits in the verbal working memory task compared to older TIA patients. Additionally, the deficits in older stroke patients were mainly in retrieval time while the deficits in younger stroke patients were mainly in accuracy. These data suggest that bihemispheric activity is necessary for older adults to successfully perform a verbal working memory task.