Intramuscular electrical stimulation of facial muscles in humans and chimpanzees: Duchenne revisited and extended

The pioneering work of Duchenne (1862/1990) was replicated in humans using intramuscular electrical stimulation and extended to another species (Pan troglodytes: chimpanzees) to facilitate comparative facial expression research. Intramuscular electrical stimulation, in contrast to the original surface stimulation, offers the opportunity to activate individual muscles as opposed to groups of muscles. In humans, stimulation resulted in appearance changes in line with Facial Action Coding System (FACS) action units (AUs), and chimpanzee facial musculature displayed functional similarity to human facial musculature. The present results provide objective identification of the muscle substrate of human and chimpanzee facial expressions- data that will be useful in providing a common language to compare the units of human and chimpanzee facial expression.     

An efficient method for estimating semantic similarity based on feature overlap: Reliability and validity of semantic feature ratings

Two studies were conducted in which human participants rated pairs of words according to the perceived degree to which the words’ referents shared semantic features. The participants found the task intuitive, simple, and quick to complete. The ratings were reliable and valid. Interrater and interstudy correlations were high, and ratings were good predictors of known feature overlap values obtained from existing semantic feature norms.     

Infants chunk object arrays into sets of individuals

Research suggests that, using representations from object-based attention, infants can represent only 3 individuals at a time. For example, infants successfully represent 1, 2, or 3 hidden objects, but fail with 4 (Developmental Science 6 (2003) 568), and a similar limit is seen in adults' tracking of multiple objects (see Cognitive Psychology 38 (1999) 259). In the present experiments we used a manual search procedure to ask whether infants can overcome this limit of 3 by chunking individuals into sets. Experiments 1 and 2 replicate infants' failure to represent a total of 4 objects. We then show that infants can exceed this limit when items are spatiotemporally grouped into two sets of 2 prior to hiding, leading infants to successfully represent a total of 4 objects. Experiment 3 demonstrates that infants tracked the 4 objects as two sets of 2, searching for each set in its correct hiding location. That infants represented the number of individuals in each set is demonstrated by their reaching for the correct number of objects in each location. These results suggest that by binding individuals into sets, infants can increase their representational capacity. This is the first evidence for chunking abilities in infants.     

Evaluating the endophenotype model of ADHD neuropsychological deficit: results for parents and siblings of children with ADHD combined and inattentive subtypes

Neurogenetic models predict neuropsychological weaknesses in the relatives of children with attention-deficit/ hyperactivity disorder (ADHD). The authors examined executive and regulatory measures in 386 relatives (307 parents, 79 siblings) of children with ADHD combined type, ADHD inattentive type, and controls. Predicted deficits were seen on trailmaking (relatives of ADHD combined type only), stop-signal reaction times (relatives of girls only), and response variability (mothers only) but not on naming or output speed. Effects generally held, even with relatives' ADHD status controlled. A neuropsychologically impaired subgroup of children with ADHD had relatives with clear neuropsychological weaknesses. The authors conclude that a neurogenetic model of ADHD etiology is supportable only for a subset of executive functions and that neuropsychological heterogeneity warrants more examination in ADHD.     

All symptoms are not created equal: the prominent role of hyperarousal in the natural course of posttraumatic psychological distress

This 3-wave longitudinal study examined the natural course of posttraumatic stress disorder symptoms using data collected from young adult survivors of community violence. Three key findings emerged. 1. Mean levels of distress for each symptom cluster decreased over time, with reexperiencing decreasing most rapidly. 2. Cross-lagged panel analysis revealed that hyperarousal strongly influences, but is not generally influenced by, other symptoms clusters. 3. Trajectory analysis demonstrated that respondents for whom hyperarousal was the most pronounced baseline symptom showed lower overall symptom improvement relative to trauma exposed counterparts for whom hyperarousal was a less prominent early symptom. Implications for theory, research, and clinical practice are discussed.     

Factors contributing to the utilization of mental health services in a rural setting

The purpose of this study was to examine if age, attitudes toward help-seeking, education, and sex were related to previous or intended future mental health utilization in a rural population. Data were collected via a mail survey from 438 adults. Regression analyses suggested that positive attitudes toward help-seeking, being female, and being younger were significantly related to both previous and intended future mental health service utilization. In addition, prior mental health use was significantly related to whether one would seek out mental health services in the future, Implications for mental health practitioners in rural settings are addressed, and limitations of the study discussed.     

Bryant's Empathy Index for children and adolescents: psychometric properties in the Spanish language

The present study investigated the following issues: (1) the structure of Bryant's Empathy Index for children and adolescents in a Spanish sample of 408 boys and 424 girls (M age=14.4 yr.), and (2) sex differences, including effect sizes and internal consistency of the scale. A principal components factor analysis with oblimin rotation showed that 20 of the index's 22 items load on three robust factors, related to Feelings of Sadness, Understanding Feelings, and Tearful Reaction with regard to the emotions of others. The 3-factor structure obtained an adequate fit to the data in the confirmatory factor analysis. Coefficients alpha ranged between .72 and .78. The 3 factors accounted for 42% of variance. As expected, girls scored higher than boys. It was concluded that the Spanish version of Bryant's Empathy Index has an acceptable reliability and construct validity, making it useful for research.