A bilateral advantage for storage in visual working memory

Various studies have demonstrated enhanced visual processing when information is presented across both visual hemifields rather than in a single hemifield (the bilateral advantage). For example, Alvarez and Cavanagh (2005) reported that observers were able to track twice as many moving visual stimuli when the tracked items were presented bilaterally rather than unilaterally, suggesting that independent resources enable tracking in the two visual fields. Motivated by similarities in the apparent capacity and neural substrates that mediate tracking and visual working memory (WM), the present work examined whether or not a bilateral advantage also arises during storage in visual WM. Using a recall procedure to assess working memory for orientation information, we found a reliable bilateral advantage; recall error was smaller with bilateral sample displays than with unilateral displays. To demonstrate that the bilateral advantage influenced storage per se rather than just encoding efficiency, we replicated the observed bilateral advantage using sequentially presented stimuli. Finally, to further characterize how bilateral presentations enhanced storage in working memory, we measured both the number and the resolution of the stored items and found that bilateral presentations lead to an increased probability of storage, rather than enhanced mnemonic resolution. Thus, the bilateral advantage extends beyond the initial selection and encoding of visual information to influence online maintenance in visual working memory.     

Monitoring same/different discrimination behavior in time and space: Finding differences and anticipatory discrimination behavior

Discrimination behavior in a standard, two-alternative forced choice same/different task is usually measured by the pigeon’s pecking one or the other of two arbitrary report areas. We found that pigeons make anticipatory, discriminative responses to the visual display during the stimulus observing period prior to the availability of the report areas; the spatial distribution of these anticipatory discriminative responses strongly correlated with the upcoming choice response. These anticipatory pecks provide evidence that the process of discrimination occurs well before the moment of choice and that key aspects of this process can be revealed by looking at the distribution of observing responses. We also manipulated the variability of the displayed items to study the nature of these anticipatory responses; again, the spatial distribution of responding during the stimulus observing period strongly correlated with the upcoming choice response. The distribution of these prechoice pecks supports the theory that pigeons search for differences in the displayed items. If differences are found, then pigeons prepare to report “different”; if not, then they report “same.”     

Quantity,not quality: the relationship between fluid intelligence and working memory capacity

A key motivation for understanding capacity in working memory (WM) is its relationship with fluid intelligence. Recent evidence has suggested a two-factor model that distinguishes between the number of representations that can be maintained in WM and the resolution of those representations. To determine how these factors relate to fluid intelligence, we conducted an exploratory factor analysis on multiple number-limited and resolution-limited measures of WM ability. The results strongly supported the two-factor model, with fully orthogonal factors accounting for performance in the number-limited and resolution-limited conditions. Furthermore, the reliable relationship between WM capacity and fluid intelligence was exclusively supported by the number factor (r=.66), whereas the resolution factor made no reliable contribution (r=−.05). Thus, the relationship between WM capacity and standard measures of fluid intelligence is mediated by the number of representations that can be simultaneously maintained in WM, rather than by the precision of those representations.     

Cognitive-Behavioral Therapy for Adolescent Body Dysmorphic Disorder

The onset of appearance-related concerns associated with body dysmorphic disorder (BDD) typically occurs in adolescence, and these concerns are often severe enough to interfere with normal development and psychosocial functioning. Cognitive behavioral therapy (CBT) is an effective treatment for adults with BDD. However, no treatment studies focusing on adolescents with BDD have been conducted. The need for an effective treatment in this population led to the development of a brief CBT protocol with family involvement. The treatment focuses on enhancing an adolescent's quality of life through the reduction of maladaptive thoughts and behaviors, and incorporates skills training and parent training. Similar treatment packages have already been shown to be efficacious for children and adolescents with similar disorders, such as obsessive-compulsive disorder and social phobia. The following case illustrates the application of this brief CBT protocol for BDD in an adolescent, and highlights clinical considerations needed when adapting CBT for a pediatric population. Treatment was associated with clinically significant improvement in symptoms of BDD, self-esteem, depression, and quality of life. This report extends extant literature by suggesting that CBT may be a helpful treatment for adolescents with BDD.     

Improving Generalization of Academic Skills: Commentary on the Special Issue

Behavior analysts have long been interested in developing and promoting the use of effective generalization strategies for behavioral interventions. Perhaps because research on academic performance has lagged behind in the field of applied behavior analysis, far less research on this topic has been conducted for academic performance problems. The purpose of this article is to comment on the six reports of experimental studies that make up this special issue. The methods investigated by the authors in this special issue are innovative and raise many intriguing questions that should fuel further research and development of strategies for improving generalized academic skills. The article concludes with thoughts about what we know as a field, and what has yet to be examined through future research.     

Approaches to Wittgenstein: Collected Papers

Book reviewed:
Brian McGuinness, Approaches to Wittgenstein: Collected Papers , Routledge, 2002, xv + 299 pp, £55.00     

Static And Dynamic Dispositions

When it comes to scientific explanation, our parsimonious tendencies mean that we focus almost exclusively on those dispositions whose manifestations result in some sort of change – changes in properties, locations, velocities and so on. Following this tendency, our notion of causation is one that is inherently dynamic, as if the maintenance of the status quo were merely a given. Contrary to this position, I argue that a complete concept of causation must also account for dispositions whose manifestations involve no changes at all, and that a causal theory that fails to include these ‘static’ dispositions alongside the dynamic ones renders static occurrences miraculous.     

Effects of COMT genotype on behavioral symptomatology in the 22q11.2 Deletion Syndrome.

The 22q11.2 Deletion Syndrome (DiGeorge/velocardiofacial syndrome) is associated with elevated rates of psychosis, and is also characterized by severe attentional difficulties and executive dysfunction. Behavioral manifestations of this syndrome could result from haploinsufficiency of the catechol-O-methyltransferase (COMT) gene, located within the 22q11 region. The goal of the present study was to examine COMT genotype in relation to behavioral symptomatology in this syndrome. Val158/108Met was genotyped in 38 patients (16 Met/-, 22 Val/-) with confirmed 22q11.2 deletions who had received the Child Behavior Checklist (CBCL) as part of a comprehensive evaluation. Results indicated that the Val genotype was associated with significantly greater internalizing and externalizing behavioral symptomatology in children with 22q11.2 deletions. Val allele status was associated with a greater-than-four-fold increase in risk for clinically significant behavior problems in children with this syndrome. These data are consistent with previous findings of increased psychopathology associated with the Val genotype in normal individuals and suggest that a functional genetic polymorphism in the 22q11 region may influence behavior in individuals with COMT haploinsufficiency.     

Improving oral reading fluency by influencing students' choice of instructional procedures: an experimental analysis with two students with behavioral disorders

Choice as an antecedent intervention has been shown to improve student behavior in a variety of ways. This investigation examined whether students could be influenced to choose whether and how to be instructed while directly measuring effects on academic performance. Using a multiple‐probe design, the reading fluency of two middle school students with Behavioral Disorders was measured repeatedly across passages. Students could earn a tangible reward for meeting a pre‐determined performance criterion in passage reading. Prior to reading the criterion passage, each student was told that he or she could choose to be instructed or not be instructed in a similar passage with high content overlap. Both students consistently chose to be instructed (as well as how they would be instructed) and stable increases in oral reading fluency were obtained. Results are discussed in terms of how motivational variables can be used to influence students' choice of instructional procedures in ways that increase their opportunities to respond and measured learning. Copyright © 2006 John Wiley & Sons, Ltd.