ASSESSMENT OF STIMULUS PREFERENCE AND REINFORCER VALUE WITH PROFOUNDLY RETARDED INDIVIDUALS

We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.     

STIMULUS (INSTRUCTIONAL) FADING DURING EXTINCTION OF SELF-INJURIOUS ESCAPE BEHAVIOR

Three individuals with developmental disabilities were exposed to a series of assessment conditions to identify the source of reinforcement for their self-injurious behavior. In each case, self-injury occurred most often in instructional (demand) situations containing a brief time-out from the task contingent on self-injury, indicating that the behavior was an escape response (i.e., maintained by negative reinforcement). Treatment was implemented in a multiple baseline across subjects design and consisted of extinction (prevention of escape) plus instructional fading (initial elimination of instructions followed by their gradual reintroduction). Results showed that the combined treatment produced immediate and large reductions in self-injury that were maintained as the frequency of instructions was increased across sessions to match the original baseline rate of presentation. Results of a component analysis conducted with 1 subject suggested that stimulus fading accelerated the behavior-reducing effects of extinction.     

A quasi-experimental investigation of message appeal variations on organ donor registration rates.

OBJECTIVE: Approximately 6,000 Americans die every year awaiting an organ transplant. Health promotion interventions may alleviate the shortage of viable organs by increasing the number of registered organ donors. This study is the first to evaluate the differential effectiveness of various organ donor messages in naturalistic settings. DESIGN: A 4 (Appeal)x4 (Exemplar)x4 (Location) counterbalanced quasi-experimental design was implemented. MAIN OUTCOME MEASURE: The behavioral outcome measure was the number of individuals who registered to be organ donors at computer kiosks. RESULTS: A number of significant main effects and interactions emerged. Most notably, of the 4 different appeals (counterargument, emotional, motivating action, dissonance), counterargument was by far the most efficacious, especially in academic-type settings (library, university, community college); the emotional appeal was most successful in hospitals. CONCLUSIONS: The findings from this study have implications for both organ donor investigations and health campaign research in general. Statistical interactions highlight the importance of evaluating multiple exemplars in multiple locations for each type of appeal when conducting health campaign research.     

Comparison between Gudjonsson Suggestibility Scale 2 (GSS2) and Bonn Test of Statement Suggestibility (BTSS) in measuring children’s interrogative suggestibility

Susceptibility of children to leading questions and interrogative pressure is an important forensic issue. The most used techniques for assessing interrogative suggestibility are the Gudjonsson Suggestibility Scales (GSS) and the Bonn Test of Statement Suggestibility (BTSS). Apart from minor differences, the two tests, investigate the same dimensions: Yield, Shift, Immediate Recall, and Total Suggestibility. In this study, to investigate correlation measures for the corresponding variables in the two tests, we individually examined 84 children from the fourth and fifth grades (44 boys and 40 girls). All the participants completed the GSS2 the BTSS-1, the Vocabulary and the Similarity subtests of the WISC-R, and Raven’s Colored Progressive Matrices. No significant gender differences were observed for any of the variables studied. Comparison between the corresponding variables for the two tests showed a positive correlation. Yield and Total Suggestibility scores correlated negatively with the three cognitive variables. We conclude that although the two suggestibility scales measure analogous variables, the BTSS seems more suitable than the GSS2 for assessing a child’s suggestibility during police and forensic interviews.     

Executive functions,impulsivity, and inhibitory control in adolescents: A structural equation model

Background. Adolescence represents a critical period for brain development, addressed by neurodevelopmental models to frontal, subcortical-limbic, and striatal activation, a pattern associated with rise of impulsivity and deficits in inhibitory control. The present study aimed at studying the association between self-report measures of impulsivity and inhibitory control with executive function in adolescents, employing structural equation modeling. Method. Tests were administered to 434 high school students. Acting without thinking was measured through the Barratt Impulsiveness Scale and the Dickman Impulsivity Inventory, reward sensitivity through the Behavioral Activation System, and sensation seeking through the Zuckerman–Kuhlman–Aluja Personali- ty Questionnaire. Inhibitory control was assessed through the Behavioral Inhibition System. The performance at the Wisconsin Card Sorting Task indicated executive function. Three models were specified using Sample Covariance Matrix, and the estimated parameters using Maximum Likelihood. Results. In the final model, impulsivity and inhibitory control predicted executive function, but sensation seeking did not. The fit of the model to data was excellent. Conclusions. The hypothesis that inhibitory control and impulsivity are predictors of executive function was supported. Our results appear informative of the validity of self-report measures to examine the relation between impulsivity traits rather than others to regulatory function of cognition and behavior.     

The Interplay Between Trust Among Peers and Interpersonal Characteristics in Homophobic Bullying Among Italian Adolescents

This study is based on exploring the trust between peers and the individual characteristics related to homophobic bullying in adolescence. Participants were 334 adolescents (141 boys and 193 girls) aged from 15 to 20 years. Participants completed the homophobic bullying scale, to investigate bullying actions towards sexual minorities, the personal attributes questionnaire, for personal characteristics, and the inventory of parent and peer attachment, to the trust between peers. The results demonstrated how female participants manifested a higher level of interpersonal traits and trust among peers than boys. Results showed how a lack of trust between peers predicts homophobic bullying. Nevertheless, we found that the lack of interpersonal characteristics represents a variable that likely mediates the relationship between lack of trust in peers and homophobic bullying. Theoretical and practical implications are discussed.     

Early changes in muscle activation patterns of toddlers during walking

Early locomotor behavior has been the focus of considerable attention by developmentalists over several decades. Few studies have addressed explicitly patterns of muscle activity that underlie this coordination pattern. Our purposes were to illustrate a method to determine objectively the onset and offset of muscle firings during early walking and to investigate the emergence of patterns of activation of the core locomotor muscles. We tested eight toddlers as they walked overground at walking onset (max. of 3-6 independent steps) and after three months of walking experience. Surface electrodes monitored activity of the gastrocnemius, tibialis anterior, quadriceps, and hamstrings. We reduced EMG signals to a frame-by-frame designation of "on-off," followed by muscle state and co-contraction analyses, and probability distributions for each muscle's activity across multiple cycles. Our results clearly show that at walking onset muscle activity was highly variable with few, if any, muscles showing recurring patterns of behavior, within or among toddlers. Variability and co-activation decreased with walking experience but remained inconsistent, in contrast to the significant increase in stability shown for joint coordination and endpoint (foot placement) parameters. We propose this trend emerges because of the high number of options (muscle combinations) available. Toddlers learn first to marshal sufficient force to balance and make forward progress but slowly discover how to optimize these resources.     

Naïve predictions of motion and orientation in mirrors: From what we see to what we expect reflections to do

The study aimed to investigate naïve beliefs regarding the dynamic and static behavior of reflections. In the first three experiments, participants in the study made predictions about the correspondence between real and reflected movements or about the orientation of the reflection of a static object placed in front of a mirror. In Experiments 1 and 2, paper-and-pencil tasks were used and in Experiment 3 participants were asked to make their predictions while imagining that they were facing a mirror. Results revealed that a percentage of undergraduates (ranging from 25% to 35%) were unable to make correct predictions. We classified the errors into types and found that responses either conform to the belief that reflections do the same or that they do the opposite. This suggests an oversimplification of the geometry of mirror reflections in two directions: participants either generalize what they see when movements are parallel to the mirror or what they see when movements are orthogonal to the mirror. Findings from Experiment 4 confirmed that these two expectations fit in with what people perceive in mirrors. Findings from Experiment 5 confirmed that this is also in agreement with the relationship perceived when looking at similar movements and orientations “outside” mirrors.     

Critical Issues in Causation and Treatment of Autism: Why Fads Continue to Flourish

The increasing incidence of autism and the lack of specific answers regarding causation have given rise to unproven educational interventions and medical treatments. Parents of a newly diagnosed child can easily fall prey to interventions that promise cures. These interventions may be harmful and, thus, pose one of the critical issues in special education today. This article will discuss some of the suspect interventions that have been popularized through the media (i.e., celebrities, journalists, and professional organizations). The authors argue that using the scientific method is clearly the antidote for pseudoscience; the need for accurate research-based decision making is apparent.