Attenuating the haptic horizontal—vertical curvature illusion

In a number of experiments, blindfolded subjects traced convex curves whose verticals were equal to their horizontal extent at the base. Overestimation of verticals, as compared with horizontals, was found, indicating the presence of a horizontal-vertical illusion with haptic curves, as well as with visible curves. Experiment 1 showed that the illusion occurred with stimuli in the frontal plane and with stimuli that were flat on the table surface in vision and touch. In the second experiment, the stimuli were rotated, and differences between vision and touch were revealed, with a stronger illusion in touch. The haptic horizontal-vertical illusion was virtually eliminated when the stimuli were bimanually touched using free exploration at the body midline, but a strong illusion was obtained when curves were felt with two index fingers or with a single hand at the midline. Bimanual exploration eliminated the illusion for smaller 2.5- through 10.2-cm stimuli, but a weakened illusion remained for the largest 12.7-cm patterns. The illusion was present when the stimuli were bimanually explored in the left and right hemispace. Thus, the benefits of bimanual exploration derived from the use of the two hands at the body midline combined with free exploration, rather than from bimanual free exploration per se. The results indicate the importance of haptic exploration at the body midline, where the body can serve as a familiar reference metric for size judgments. Alternative interpretations of the results are discussed, including the impact of movement-based heuristics as a causal factor for the illusion. It was suggested that tracing the curve’s peak served to bisect the curve in haptics, because of the change in direction.     

Subtypes of Psychopathology in Children Referred for Neuropsychological Assessment

The validity of a Personality Inventory for Children-Revised edition (PIC-R) typology was examined in a sample of 323 children aged 6–16 years. These children had been referred to a children's mental health centre for neuropsychological assessment. In study 1, K-means cluster analysis (k = 12) was applied to the PIC clinical scales in an attempt to replicate the 12 clusters identified by Gdowski, Lachar, and Kline (1985). Partial cluster replication was achieved. Examination of the obtained clusters revealed significant overlap, suggesting that fewer clusters would represent an optimal solution. In study 2, a two-stage cluster analysis yielded a seven-cluster solution consistent with several key forms of psychopathology previously reported in the literature using specific neuropsychological populations. Identified subtypes included profiles characterized as: normal, cognitive deficit, cognitive deficit with internalized psychopathology, cognitive deficit with social impairment, cognitive deficit with hyperactivity, cognitive deficit with both internalized and externalized psychopathology, and combined internalized and externalized psychopathology without a cognitive deficit component.     

Evaluation of stimulus control over a communication response as an intervention for stereotypical responding

Stereotypical behavior maintained by automatic reinforcement often does not result in harm but may be undesirable in some situations. In the current investigation, participants were 2 individuals who engaged in nonharmful stereotypical responses shown in an analogue functional analysis to be insensitive to social contingencies. After bringing these responses under stimulus control using differential punishment, both participants learned a mand to terminate punishment for stereotypy. We also assessed whether the mand could be brought under stimulus control.     

Factors Influencing Experienced Distress and Attitude Toward Trauma by Emergency Medicine Practitioners

Authors explored whether the dose-response relationship evident in PTSD also applied to cases of vicarious trauma and, if so, which variables serve to moderate such reactions. This study examined the surveyed responses of emergency care workers in a group geographically near the September 11, 2001 New York terrorist site, comparing the results to a group of emergency care workers geographically distant from the terrorist site. Study results lend support to the presence of a dose-response relationship within vicarious traumatization. Specific variables associated with higher distress levels for practitioners included the discipline of the practitioner, treating an injured victim, and personally knowing a victim of the New York terrorist attacks. Past training related to vicarious traumatization was not associated with lower distress levels for practitioners. In addition, practitioners' awareness and interest in psychological issues related to trauma appear to have been enhanced by geographic proximity to the New York terrorist attacks.