Psychometric properties of the children's atypical development scale

The Children's Atypical Development Scale (CADS) is a 53-item rating scale designed to measure unusual behaviors in children. Principal-factor analysis on a clinic-referred and pediatric sample of 474 children resulted in a four-factor solution: Communication Deficits, Lability, Social Relatedness Deficits, and Preoccupation. The CADS is internally consistent and has adequate temporal stability. CADS factor scores were differentially associated with parent and teacher rating scales, IQ, and Continuous Performance Test errors. The scale shows promise as a clinical and research tool for assessing atypical behaviors associated with pervasive developmental disorder and other neurobehavioral disorders.This research was supported in part by a grant from the Smart Family Foundation. The authors are grateful to James P. O'Donnell, Catherine Lord, and Frank A. Zelko for their comments on an earlier draft.     

Correlations among within-channel and between-channel auditory gap-detection thresholds in normal listeners

We obtained data on within-channel and between-channel auditory temporal gap-detection acuity in the normal population. Ninety-five normal listeners were tested for gap-detection thresholds, for conditions in which the gap was bounded by spectrally identical, and by spectrally different, acoustic markers. Separate thresholds were obtained with the use of an adaptive tracking method, for gaps delimited by narrowband noise bursts centred on 1.0 kHz, noise bursts centred on 4.0 kHz, and for gaps bounded by a leading marker of 4.0 kHz noise and a trailing marker of 1.0 kHz noise. Gap thresholds were lowest for silent periods bounded by identical markers--'within-channel' stimuli. Gap thresholds were significantly longer for the between-channel stimulus--silent periods bounded by unidentical markers (p < 0.0001). Thresholds for the two within-channel tasks were highly correlated (R = 0.76). Thresholds for the between-channel stimulus were weakly correlated with thresholds for the within-channel stimuli (1.0 kHz, R = 0.39; and 4.0 kHz, R = 0.46). The relatively poor predictability of between-channel thresholds from the within-channel thresholds is new evidence on the separability of the mechanisms that mediate performance of the two tasks. The data confirm that the acuity difference for the tasks, which has previously been demonstrated in only small numbers of highly trained listeners, extends to a population of untrained listeners. The acuity of the between-channel mechanism may be relevant to the formation of voice-onset time-category boundaries in speech perception.     

Semantic processing of mathematical gestures

Objective

To examine whether or not university mathematics students semantically process gestures depicting mathematical functions (mathematical gestures) similarly to the way they process action gestures and sentences. Semantic processing was indexed by the N400 effect.

Results

The N400 effect elicited by words primed with mathematical gestures (e.g. “converging” and “decreasing”) was the same in amplitude, latency and topography as that elicited by words primed with action gestures (e.g. drive and lift), and that for terminal words of sentences.

Significance and conclusion

Findings provide a within-subject demonstration that the topographies of the gesture N400 effect for both action and mathematical words are indistinguishable from that of the standard language N400 effect. This suggests that mathematical function words are processed by the general language semantic system and do not appear to involve areas involved in other mathematical concepts (e.g. numerosity).     

A link between altruism and sexual selection: Genetic influence on altruistic behaviour and mate preference towards it

Altruistic behaviour raises major questions for psychology and biology. One hypothesis proposes that human altruistic behaviour evolved as a result of sexual selection. Mechanisms that seek to explain how sexual selection works suggest genetic influence acting on both the mate preference for the trait and the preferred trait itself. We used a twin study to estimate whether genetic effects influenced responses to psychometric scales measuring mate preference towards altruistic traits (MPAT) and the preferred trait (i.e., ‘altruistic personality’). As predicted, we found significant genetic effects influencing variation in both. We also predicted that individuals expressing stronger MPAT and ‘altruistic personality’ would have mated at a greater frequency in ancestral populations. We found evidence for this in that 67% of the covariance in the phenotypic correlation between the two scales was associated with significant genetic effects. Both sets of findings are thus consistent with the hypothesized link between sexual selection and human altruism towards non‐kin. We discuss how this study contributes to our understanding of altruistic behaviour and how further work might extend this understanding.     

Antecedents of Leader Utilization of Staff Input in Decision-Making Teams

The purpose of this experiment was to explore the possibility that the inconsistent findings of Brehmer and Hagafors (1986,Organizational Behavior and Human Decision Processes, 38, 181–195), Sniezek and Buckley (1995,Organizational Behavior and Human Decision Processes, 62, 159–174), and leader–member exchange research regarding leaders' propensity todifferentiallyandaccuratelyweight staff input can be explained as a result of experience, the availability to the leader of staff member judgment confidence, and the cumulative past accuracy of each staff member. The availability to the team leader of staff member past judgment accuracy and staff member judgment confidence was provided in an environment in which differential staff weighting was the appropriate staff utilization strategy. Eighty-four leaders of four-person decision-making teams performed 63 decisions on a computerized decision-making task. Both experience and providing leaders with cumulative staff past accuracy information were related to greater staff weighting variability and greater staff weighting accuracy. Although positively related to staff weighting, staff confidence information did not improve leader weighting variability nor actual staff weighting accuracy.     

An investigation into the perception of dominance from schematic faces: A study using the World-Wide Web

The World-Wide Web (WWW) is considered to be a viable tool for scientific research, and several investigators have already made use of it in their studies. Although the WWW allows researchers to access a vast subject pool, questions of reliability and validity need to be addressed before it is incorporated into mainstream research. By replicating, on the Internet, an existing study (Keating, Mazur, & Segall, 1977) on the perception of schematic faces, we were able to conclude that experimental work carried out in this manner is not necessarily biased by the medium. One difference from previous work was the effect of a smiling versus a nonsmiling face on the perception of dominance, given an identical brow position for the two faces. This was replicated on a different occasion with different subjects, which may represent a shift in attitudes to this facial configuration since the original study was conducted. Young North American males were overrepresented in our sample, but comparison with other surveys indicates that the population sampled by the Internet is becoming more representative.     

The relationship of body dysmorphic disorder and eating disorders to obsessive-compulsive disorder

Body dysmorphic disorder (BDD) and eating disorders are body image disorders that have long been hypothesized to be related to obsessive-compulsive disorder (OCD). Available data suggest that BDD and eating disorders are often comorbid with OCD. Data from a variety of domains suggest that both BDD and eating disorders have many similarities with OCD and seem related to OCD. However, these disorders also differ from OCD in some ways. Additional research is needed on the relationship of BDD and eating disorders to OCD, including studies that directly compare them to OCD in a variety of domains, including phenomenology, family history, neurobiology, and etiology.