Event-related fMRI of category learning: differences in classification and feedback networks

Eighteen healthy young adults underwent event-related (ER) functional magnetic resonance imaging (fMRI) of the brain while performing a visual category learning task. The specific category learning task required subjects to extract the rules that guide classification of quasi-random patterns of dots into categories. Following each classification choice, visual feedback was presented. The average hemodynamic response was calculated across the eighteen subjects to identify the separate networks associated with both classification and feedback. Random-effects analyses identified the different networks implicated during the classification and feedback phases of each trial. The regions included prefrontal cortex, frontal eye fields, supplementary motor and eye fields, thalamus, caudate, superior and inferior parietal lobules, and areas within visual cortex. The differences between classification and feedback were identified as (i) overall higher volumes and signal intensities during classification as compared to feedback, (ii) involvement of the thalamus and superior parietal regions during the classification phase of each trial, and (iii) differential involvement of the caudate head during feedback. The effects of learning were then evaluated for both classification and feedback. Early in learning, subjects showed increased activation in the hippocampal regions during classification and activation in the heads of the caudate nuclei during the corresponding feedback phases. The findings suggest that early stages of prototype-distortion learning are characterized by networks previously associated with strategies of explicit memory and hypothesis testing. However as learning progresses the networks change. This finding suggests that the cognitive strategies also change during prototype-distortion learning.     

A decision theoretic and prototype conceptualization of possible selves: implications for the prediction of risk behavior

The present study explores a new framework for conceptualizing possible selves for the prediction of behavior. The framework uses decision theory, attitude theory, and classic expectancy-value models. The focus is on using possible-self constructs that (a) correspond to behavioral alternatives, (b) focus on self dimensions directly tied to the behavioral criterion, and (c) use expectancy-value constructs to assess the core features of a given possible self-dimension. A study of 305 college students was undertaken to predict alcohol use from possible self constructs using the framework. Results affirmed the utility of the approach, showing that possible-self constructs predicted behavior over and above current self-image and constructs in the Theory of Planned Behavior. Possible-self constructs associated with negative attributes of both binge drinkers and nonbinge drinkers were predictive of behavior.     

Non-symbolic arithmetic abilities and mathematics achievement in the first year of formal schooling

We examine the nature of motor representations evoked during comprehension of written sentences describing hand actions. We distinguish between two kinds of hand actions: a functional action, applied when using the object for its intended purpose, and a volumetric action, applied when picking up or holding the object. In Experiment 1, initial activation of both action representations was followed by selection of the functional action, regardless of sentence context. Experiment 2 showed that when the sentence was followed by a picture of the object, clear context-specific effects on evoked action representations were obtained. Experiment 3 established that when a picture of an object was presented alone, the time course of both functional and volumetric actions was the same. These results provide evidence that representations of object-related hand actions are evoked as part of sentence processing. In addition, we discuss the conditions that elicit context-specific evocation of motor representations.     

The effects of exergaming on physical activity among inactive children in a physical education classroom

Childhood obesity, which is due in part to lack of physical activity, is a serious concern that requires the attention of the behavioral community. Although excessive video game play has been noted in the literature as a contributor to childhood obesity, newer video gaming technology, called exergaming, has been designed to capitalize on the reinforcing effects of video games to increase physical activity in children. This study evaluated the effects of exergaming on physical activity among 4 inactive children in a physical education (PE) classroom. Results showed that exergaming produced substantially more minutes of physical activity and more minutes of opportunity to engage in physical activity than did the standard PE program. In addition, exergaming was socially acceptable to both the students and the PE teacher. Exergaming appears to hold promise as a method for increasing physical activity among inactive children and might be a possible intervention for childhood obesity.     

Learning of monotonic and nonmonotonic sequences in domesticated horses (Equus callabus) and chickens (Gallus domesticus)

[Hulse and Dorsky, 1977] and [Hulse and Dorsky, 1979] found that rats, like humans, learn sequences following a simple rule-based structure more quickly than those lacking a rule-based structure. Through two experiments, we explored whether two additional species—domesticated horses (Equus callabus) and chickens (Gallus domesticus)—would show this same propensity. In both experiments, subjects encountered either a structured or unstructured sequence of food quantities in a runway paradigm. In both experiments, subjects exposed to structured patterns of food quantities learned to track sequences of food quantities more efficiently than those exposed to patterns lacking such structure by running fast for large food quantities and slowly for small food quantities. These results provide evidence that horses and chickens track simple sequences similarly to humans and rats.     

Peer influence on event reports among adolescents and young adults

When two or more people witness an event together, the event report from one person can influence others’ reports. In the current study we examined the role of age and motivational factors on peer influence regarding event reports in adolescents and young adults. Participants (N=249) watched a short video of a robbery then answered questions with no co-witness information or with information believed to be from a co-witness. Public and private response conditions were included to explore motivations for peer influence. Co-witness information influenced participants’ responses, although the effect was equally strong in the private and the public co-witness conditions. Peer influence on event reports was steady across a large age range (11- to 25-year-olds).     

Organizational Citizenship Behavior in Sport: Relationships with Leadership,Team Cohesion,and Athlete Satisfaction

The purpose of this study was to introduce the construct of organizational citizenship behavior (OCB; Organ, 1988 Organ, D. W. 1988. Organizational citizenship behavior: The good soldier syndrome, Lexington, MA: Lexington Books. [Crossref] , [Google Scholar]) into the sport psychology literature and examine its utility in sport. Based upon OCB research in the organizational literature, the Multidimensional Model of Leadership (MML; Chelladurai, 1978 Chelladurai, P. 1978. “A contingency model of leadership in athletics”. In Unpublished doctoral dissertation, Waterloo: University of Waterloo, Canada.  [Google Scholar]), the conceptual framework of team cohesion (CFC; Carron & Hausenblas, 1998 Carron, A. V. and Hausenblas, H. A. 1998. Group dynamics in sport, 2nd., Morgantown, WV: Fitness Information Technology.  [Google Scholar]), and a model of athlete satisfaction (MAS; Chelladurai & Riemer, 1997 Chellardurai, P. and Riemer, H. A. 1997. A classification of facets of athlete satisfaction. Journal of Sport Management, 11: 133–159.  [Google Scholar]) were selected as theoretically sound antecedents to be associated with OCB in sport. A total of 193 student-athletes from a large Division I university and a smaller Division III university representing a variety of sports participated in the study. Results of the study provide preliminary evidence for OCB as a unique and meaningful construct in sport and support many of the predictions hypothesized in the MML, CFC, and MAS. Results are discussed in the context of previous literature as well as theoretical, research, and practical implications.     

The Science and Ethics of Placebo in Pediatric Psychopharmacology

Pediatric psychopharmacology is a relatively new science. Although the use of psychotropic medications in children has risen in the past decade, there are few standard treatments for serious psychiatric or developmental disorders of childhood. The relative absence of standard treatments is further complicated by the fact that many of the agents used in pediatric psychopharmacology have been adapted from other fields. Therefore, investigators have a responsibility to make incremental progress from concept through pilot studies and large-scale, multisite efficacy and safety trials. Thus, although there is a pressing need to conduct medication trials that can guide clinical practice, there are scientific and ethical considerations to bear in mind when designing clinical trials in pediatric psychopharmacology. This article reviews essential ethical and scientific issues that are relevant to designing clinical trials in children with psychiatric and developmental disorders. Using examples from recently published literature, the article describes the challenges and pitfalls of various clinical trial study designs. The application of sound ethical and scientific principles is necessary to ensure that clinical trials are properly conducted and to guard against ambiguous results that can not guide practice.