Behavioral group treatment for obsessive-compulsive disorder in adolescence: a pilot study

This pilot study is a preliminary evaluation of the effectiveness of a cognitive-behavioral outpatient group treatment (CBT) protocol for adolescents with Obsessive-Compulsive Disorder (OCD). Seven adolescents were treated in a 10-session group CBT program with weekly 2-hour sessions. The treatment protocol was an adaptation of approaches with established effectiveness and emphasized three main components: externalizing the OCD by cultivating mindful detachment; exposure and response prevention (ERP); and refocusing on alternative, constructive behaviors following exposure. An occupational therapy component played a significant role in designing creative exposure and refocusing challenges. Self-report measures at pre, post, and 12-month follow-up suggested clinical improvements for 5 of the 7 patients, thus partially supporting a group treatment format for adolescents with mild to moderate OCD.     

Processing of contour closure by baboons (Papio papio)

This study investigated the Gestalt law of closure in baboons. Using a computer-controlled self-testing procedure, we trained baboons (Papio papio) to discriminate open versus closed shapes presented on a touch screen with a two-alternative forced choice procedure. Ten baboons (OPEN + group) were trained with the open shapes serving as the positive stimulus (S+), and nine others (CLOSE + group) were trained with the closed shape serving as S+. The OPEN + group obtained higher discrimination performance than the CLOSE + group (Exp 1), but its scores declined when new line segments were added to the stimuli (Exp 2) and after smoothing the end points of the open shapes (Exp 3). The CLOSE + group was less affected by the above manipulations of local stimulus dimension, but its performance was disrupted when the collinearity end points was reduced (Exp 3). Use of a visual search task revealed that the search for an open shape among closed distractors was less attention demanding in baboons than the search for a closed shape among open ones (Exp 4). It is concluded that (1) end lines rather than closeness per se are perceptual primitives for the open versus closed discrimination in baboons, and (2) the relative emphasis on local or configural cues when processing contour closure depends on experiential factors in baboons and is thus subject to interindividual variations.     

Contemporary theories of 1/f noise in motor control

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.     

Body-based perceptual rescaling revealed through the size-weight illusion

An embodied approach to the perception of spatial layout contends that the body is used as a 'perceptual ruler' with which individuals scale the perceived environmental layout. In support of this notion, previous research has shown that the perceived size of objects can be influenced by changes in the apparent size of hand. The size-weight illusion is a well known phenomenon, which occurs when people lift two objects of equal weight but differing sizes and perceive that the larger object feels lighter. Therefore, if apparent hand size influences perceived object size, it should also influence the object's perceived weight. In this study, we investigated this possibility by using perceived weight as a measure and found that changes in the apparent size of the hand influence objects' perceived weight.     

How useful are landmarks when learning a route in a virtual environment? Evidence from typical development and Williams syndrome

The ability to learn a route through a virtual environment was assessed in 19 older children and adults with Williams syndrome (WS) and 40 typically developing (TD) children aged 6-9 years. In addition to comparing route-learning ability across groups, we were interested in whether participants show an adult-like differentiation between "useful" and "less useful" landmarks when learning a route and the relative salience of landmark position versus landmark identity. Each virtual environment consisted of a brick wall maze with six junctions. There were 16 landmarks in the maze, half of which were on the correct path and half on incorrect paths. Results showed that both groups could learn each route to criterion (two successful completions of a route without error). During the learning phase, the WS group produced more errors than the TD group and took longer to reach criterion. This was predominantly due to the large number of perseverative errors (i.e., errors that were made at the same choice point on consecutive learning trials) made by the WS group relative to the TD children. We suggest that this reflects a difficulty in inhibiting erroneous responses in WS. During the test phase, the TD group showed stronger recall of landmarks adjacent to junctions (more useful landmarks) than of landmarks along path sections (less useful landmarks) independent of each individual's level of nonverbal ability. This pattern was also evident in the WS group but was related to level of nonverbal maturation; the differentiation between recall of junction and path landmarks increased as nonverbal ability increased across WS participants. Overall, the results demonstrate that individuals with WS can learn a route but that the development of this ability is atypical.     

Approximate entropy normalized measures for analyzing social neurobiological systems

When considering time series data of variables describing agent interactions in social neurobiological systems, measures of regularity can provide a global understanding of such system behaviors. Approximate entropy (ApEn) was introduced as a nonlinear measure to assess the complexity of a system behavior by quantifying the regularity of the generated time series. However, ApEn is not reliable when assessing and comparing the regularity of data series with short or inconsistent lengths, which often occur in studies of social neurobiological systems, particularly in dyadic human movement systems. Here, the authors present two normalized, nonmodified measures of regularity derived from the original ApEn, which are less dependent on time series length. The validity of the suggested measures was tested in well-established series (random and sine) prior to their empirical application, describing the dyadic behavior of athletes in team games. The authors consider one of the ApEn normalized measures to generate the 95th percentile envelopes that can be used to test whether a particular social neurobiological system is highly complex (i.e., generates highly unpredictable time series). Results demonstrated that suggested measures may be considered as valid instruments for measuring and comparing complexity in systems that produce time series with inconsistent lengths.     

Race is gendered: how covarying phenotypes and stereotypes bias sex categorization

We argue that race and sex categories are psychologically and phenotypically confounded, affecting social categorizations and their efficiency. Sex categorization of faces was facilitated when the race category shared facial phenotypes or stereotypes with the correct sex category (e.g., Asian women and Black men) but was impaired when the race category shared incompatible phenotypes or stereotypes with the correct sex category (e.g., Asian men and Black women). These patterns were evident in the disambiguation of androgynous faces (Study 1) and the efficiency of judgments (Studies 1, 2, 4, and 5). These patterns emerged due to common facial phenotypes for the categories Black and men (Studies 3 and 5) and due to shared stereotypes among the categories Black and men and the categories Asian and women (Studies 4 and 5). These findings challenge the notion that social categories are perceived independent of one another and show, instead, that race is gendered.     

Investigating the interaction between schizotypy, divergent thinking and cannabis use

Cannabis acutely increases schizotypy and chronic use is associated with elevated rates of psychosis. Creative individuals have higher levels of schizotypy, however links between cannabis use, schizotypy and creativity have not been investigated. We investigated the effects of cannabis smoked naturalistically on schizotypy and divergent thinking, a measure of creativity. One hundred and sixty cannabis users were tested on 1 day when sober and another day when intoxicated with cannabis. State and trait measures of both schizotypy and creativity were administered. Quartile splits compared those lowest (n=47) and highest (n=43) in trait creativity. Cannabis increased verbal fluency in low creatives to the same level as that of high creatives. Cannabis increased state psychosis-like symptoms in both groups and the high creativity group were significantly higher in trait schizotypy, but this does not appear to be linked to the verbal fluency change. Acute cannabis use increases divergent thinking as indexed by verbal fluency in low creatives.     

The structure of cognitive abilities in youths with manic symptoms: a factorial invariance study

This study compared the structure of cognitive ability (specifically, verbal/crystallized [Gc] and visual-spatial ability [Gv]), as measured in the Wechsler Intelligence Scale for Children, in youth with manic symptoms with a nationally representative group of similarly aged youth. Multigroup confirmatory factor analysis found the majority of the estimated parameters were invariant between the groups, although there was a difference in the intercepts for the Similarities subtest and difference in unique variances for the Picture Completion, Comprehension, and Picture Arrangement subtests. Thus, although there are many neurological changes associated with manic symptoms, the structure of verbal/crystallized and visual-spatial abilities appear relatively robust and invariant. As Gc and Gv are the primary domains on all the Wechsler Intelligence Scales for Children, results also indicate that clinical interpretation of the Wechsler scales may be appropriate to measure cognitive performance in youths with manic symptoms.