Estimation of psychometric functions from adaptive tracking procedures

Because adaptive tracking procedures are designed to avoid stimulus levels far from a target threshold value, the psychometric function constructed from the trial-by-trial data in the track may be accurate near the target level but a poor reflection of performance at levels far removed from the target. A series of computer simulations was undertaken to assess the reliability and accuracy of psychometric functions generated from data collected in up-down adaptive tracking procedures. Estimates of psychometric function slopes were obtained from-trial-by-trial data in simulated adaptive tracks and compared with the true characteristics of the functions used to generate the tracks. Simulations were carried out for three psychophysical procedures and two target performance levels, with tracks generated by psychometric functions with three different slopes. The functions reconstructed from the tracking data were, for the most part, accurate reflections of the true generating functions when at least 200 trials were included in the tracks. However, for 50- and 100-trial tracks, slope estimates were biased high for all simulated experimental conditions. Correction factors for slope estimates from these tracks are presented. There was no difference in the accuracy and reliability of slope estimation due to -target-level-for the adaptive track, and only minor differences due to psychophysical procedure. It is recommended that, if both threshold and slope of psychometric functions are to be estimated-from the trial-by-trial tracking data, at least 100 trials should be included in the tracks, and a three- or four-alternative forced-choice procedure should be used. However, good estimates can also be obtained using the two-alternative forced-choice procedure or less than 100 trials if appropriate corrections for bias are applied.     

TOO MUCH REINFORCEMENT,TOO LITTLE BEHAVIOR: ASSESSING TASK INTERSPERSAL PROCEDURES IN CONJUNCTION WITH DIFFERENT REINFORCEMENT SCHEDULES WITH AUTISTIC CHILDREN

Task interspersal procedures have been quite effective in increasing autistic children's motivation to learn. These procedures have typically demonstrated that the inclusion of reinforced maintenance tasks (previously learned tasks) increases responding to new acquisition tasks because more reinforcers, in general, are available. However, studies have not specifically addressed the effects of various schedules of reinforcement, used in conjunction with task interspersal procedures, upon response acquisition. In the present study, a multiple baseline design across subjects was used to assess different reinforcement schedules. Five autistic children participated in learning sessions, during which trials of an acquisition task were interspersed with trials of three maintenance tasks. Correct responses to acquisition tasks were continuously reinforced throughout all conditions, while the reinforcement schedule for competent performance of maintenance tasks differed systematically. Results indicated that all children learned the new tasks when food reinforcers were presented only for acquisition tasks. Results are discussed in terms of behavioral contrast and improving the effectiveness of motivation-enhancing procedures for autistic children.     

Primary influencers of initial vocational choices for college women

This study of 597 entering college women investigated the characteristics of people they named as the primary influencers for their initial choices of major. College major was considered analogous to vocational field since the sample of students overwhelmingly gave career goals as reasons for choosing a particular major. Characteristics of these primary influencers were compared with those of a sample of individuals influencing male choices. In addition, characteristics of influencers were compared between those influencing females choosing traditional and nontraditional majors. The results indicate that most students, regardless of gender, were influenced by males, particularly fathers. However, a notable percentage of female students, especially those in traditional fields, were influenced by females. Students whose primary influencers were in fields closely related to their own vocational choices reported being more certain of their choices than students citing influencers in unrelated fields. These findings have implications for model-observer similarity, and may necessitate distinguishing between influential people who provide reinforcement for a choice of major and those who provide specific vocational modeling as well as reinforcement for that choice.     

Are Average Facial Configurations Attractive Only Because of Their Symmetry?

Abstract—Several commentators have suggested that the attractiveness of average facial configurations could be due solely to associated changes in symmetry. If this symmetry hypothesis is correct, then averageness should not account for significant variance in attractiveness ratings when the effect of symmetry is partialed out. Furthermore, changes in attractiveness produced by manipulating the averageness of individual faces should disappear when all the images are made perfectly symmetric. The experiments reported support neither prediction. Symmetry and averageness (or distinctiveness, the converse of averageness) made independent contributions to attractiveness (Experiments 1 and 2), and changes in attractiveness resulting from changes in averageness remained when the images were made perfectly symmetric (Experiment 2). These results allow us to reject the symmetry hypothesis, and strengthen the evidence that facial averageness is attractive.     

Utilizing ret for effective treatment of adult children of alcoholics

Adult Children of Alcoholics (ACOAs) are a recognized clinical population that includes approximately one of every eight Americans. Although there has been a great deal of interest in this population, studies indicate that only 5% of ACOAs receive effective treatment. The authors assert that Rational-Emotive Therapy can provide ACOAs the education, expression of suppressed feelings, and cognitive restructuring that research indicates is necessary for recovery. This paper discusses issues associated with ACOAs and methods of using RET with this population.Marjorie E. Ferstein, M.S., is an Advisor in the Judicial Program of the University of Georgia.Susan C. Whiston is an Assistant Professor at the University of Nevada, Las Vegas.     

Multiple reinforcement contingencies to reduce aggression,self-injury and dysfunctional verbal behaviors in an adult who is sensory impaired

Differential reinforcement of other behavior (DRO) and differential reinforcement of low rates of responding (DRL) have been effective techniques in reducing maladaptive behaviors in therapeutic settings. Reported studies of these reinforcement-based procedures indicate that they are usually implemented in isolation, targeting only a single behavior or class of behaviors. In this study, multiple DRO and DRL contingencies were utilized concurrently in reducing two distinct classes of behaviors with a 26 year-old blind man with moderate retardation. One class of behaviors included socially inappropriate verbalizations, while the other included aggressive, self-injurious and environmentally destructive behaviors. Distinct contingencies were established according to the functions of the targeted behaviors and their severity and separate schedules of reinforcement were derived from baseline frequencies. Over a period of 20 months, the differential reinforcement interventions resulted in rapid reduction of behaviors in both classes to near-zero rates and frequencies were maintained at this low level while contingency schedules were systematically lengthened. Collateral effects are discussed including performance in functional academics and participation in community integration activities.