Working memory dynamics bias the generation of beliefs: The influence of data presentation rate on hypothesis generation

Although temporal dynamics are inherent aspects of diagnostic tasks, few studies have investigated how various aspects of time course influence hypothesis generation. An experiment is reported that demonstrates that working memory dynamics operating during serial data acquisition bias hypothesis generation. The presentation rate (and order) of a sequence of serially presented symptoms was manipulated to be either fast (180 ms per symptom) or slow (1,500 ms per symptom) in a simulated medical diagnosis task. When the presentation rate was slow, participants chose the disease hypothesis consistent with the symptoms appearing later in the sequence. When the presentation rate was fast, however, participants chose the disease hypothesis consistent with the symptoms appearing earlier in the sequence, therefore representing a novel primacy effect. We predicted and account for this effect through competitive working memory dynamics governing information acquisition and the contribution of maintained information to the retrieval of hypotheses from long-term memory.     

Early Predictors of Urban Adolescents’ Community Violence Exposure

This study examined the extent to which individual, peer, and family factors predicted the onset of community violence exposure in middle and high school, as well as the indirect effects of early factors. We were particularly interested in the timing of exposure to community violence during adolescence, and thus conducted survival analyses on data from 632 urban youth, followed from first grade through high school. Early aggressive behavior and poor academic readiness were associated with an earlier onset of community violence exposure in adolescence. The effects of early aggression on community violence exposure and victimization were accounted for, in part, by peer rejection and deviant peer affiliation; there was no evidence of moderation by gender or parental monitoring. Findings highlight potential targets for preventive interventions with youth at risk of community violence exposure.     

Divided attention: An undesirable difficulty in memory retention

How can we improve memory retention? A large body of research has suggested that difficulty encountered during learning, such as when practice sessions are distributed rather than massed, can enhance later memory performance (see R. A. Bjork & E. L. Bjork, 1992). Here, we investigated whether divided attention during retrieval practice can also constitute a desirable difficulty. Following two initial study phases and one test phase with Swahili–English word pairs (e.g., vuvi–snake), we manipulated whether items were tested again under full or divided attention. Two days later, participants were brought back for a final cued-recall test (e.g., vuvi–?). Across three experiments (combined N = 122), we found no evidence that dividing attention while practicing retrieval enhances memory retention. This finding raises the question of why many types of difficulty during practice do improve long-term retention, but dividing attention does not.     

Sailing between Scylla and Charybdis1: Incorporating qualitative approaches into child psychotherapy research

Starting from the acknowledged gap between research and practice in child psychotherapy, this paper offers an historical perspective on the relation between these two activities, and suggests that qualitative approaches to research may offer new ways of bringing them together. After introducing the fundamental concepts of qualitative analysis, three areas where qualitative forms of research may be useful to child psychotherapists are explored: relevant but non-psychotherapy research; accounts of therapy research; and therapy process research. Examples of all of these types of research are presented, and some of the challenges to incorporating qualitative approaches into child psychotherapy research are discussed.     

Simulated Visual Field Loss Does Not Alter Turning Coordination in Healthy Young Adults

Turning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.     

Young adult e-cigarette users’ reasons for liking and not liking e-cigarettes: A qualitative study

Objective: To gain an in-depth understanding of what young adult electronic- or e-cigarette users like or dislike about e-cigarettes. We aimed to determine the reasons that may encourage young adults to use e-cigarettes or discourage them from using e-cigarettes.

Design: Twelve focus group discussions were conducted with 62 current daily e-cigarette users (63% men) of mean age = 25.1 years (standard deviation = 5.5). Data were analysed following principles of inductive content analysis.

Results: Results indicated 12 categories of reasons for liking e-cigarettes (e.g. recreation, smoking cessation) and 6 categories of reasons for not liking e-cigarettes (e.g. poor product quality, poor smoking experience).

Conclusions: Young adults’ motives for using or not using e-cigarettes appear to be varied and their relative importance in terms of predicting e-cigarette use initiation, dependence, and cigarette/e-cigarette dual use needs to be carefully studied in population-based, empirical studies. The current findings suggest that e-cigarettes may serve social, recreational, and sensory expectancies that are unique relative to cigarettes and not dependent on nicotine. Further, successful use of e-cigarettes in smoking cessation will likely need higher standards of product quality control, better nicotine delivery efficiency and a counselling component that would teach smokers how to manage e-cigarette devices while trying to quit smoking cigarettes.     

Memory for Faces in Children with Autism

Previous research has established that children with Autistic Disorder have deficits in aspects of social cognition and in verbal memory, but research on social memory is limited. Twenty-four autistic boys aged 7 to 12 years and normal controls matched for verbal mental age were administered parallel social and nonsocial matching and memory tasks. Results showed that the children with autism were impaired relative to the normal children on the social (face) memory task only. Furthermore, of the four experimental tasks, the social memory task had the highest and most consistent correlations with measures of social development and adaptive skills. Whereas the normal children used the special status of faces to recall them more easily than objects, the children with autism showed equal recall of objects and faces.     

The Peierls-Nabarro model revisited

We re-examine two important issues within the Peierls-Nabarro model, which are critical in obtaining accurate values for the Peierls stress. The first is related to the sampling scheme (double versus single counting) of the misfit energy across the glide plane and the second is the effect of atomic relaxation on the Peierls stress. We argue that the double-counting scheme is physically more appropriate. An analytical formula is derived for the Peierls stress of dislocations in alternating lattices. The atomic relaxation is shown to play an important role on the Peierls stress for narrow dislocations.     

The effects of distinctiveness on memory and metamemory for face–name associations

We examined the influence of face and name distinctiveness on memory and metamemory for face–name associations. Four types of monitoring judgements were solicited during encoding and retrieval of face–name pairs that contained distinct or typical faces (Experiment 1) or names (Experiment 2). The beneficial effects of distinctiveness on associative memory were symmetrical between faces and names, such that relative to their typical counterparts, distinct faces enhanced memory for names, and distinct names enhanced memory for faces. These effects were also apparent in metamemory. Estimates of prospective and retrospective memory performance were greater for face–name associations that contained a distinct face or name compared with a typical face or name, regardless of whether the distinct item was a cue or target. Moreover, the predictive validity of prospective monitoring improved with name distinctiveness, whereas the predictive validity of retrospective monitoring improved with facial distinctiveness. Our results indicate that distinctiveness affects not only the strength of the association between a face and a name, but also the ability to monitor that association.