Bayesian estimation of item response curves

Item response curves for a set of binary responses are studied from a Bayesian viewpoint of estimating the item parameters. For the two-parameter logistic model with normally distributed ability, restricted bivariate beta priors are used to illustrate the computation of the posterior mode via the EM algorithm. The procedure is illustrated by data from a mathematics test.This work was supported under Contract No. N00014-85-K-0113, NR 150-535, from Personnel and Training Research Programs, Psychological Sciences Division, Office of Naval Research. The authors wish to thank Mark D. Reckase for providing the ACT data used in the illustration and Michael J. Soltys for computational assistance. They also wish to thank the editor and four anonymous reviewers for many valuable suggestions.     

The effects of number of responses on the postreinforcement pause in fixed-interval schedules

The present study manipulated the number of responses in a modified fixed-interval schedule by imposing a blackout after each unreinforced response during the interval. The blackout duration was varied, and the duration of the fixed interval was held constant. The subjects were initially exposed to a fixed-interval 300-sec schedule. Blackout durations of 0, 10, and 50 sec were used. Following this, a fixed-interval 30-sec schedule was used with blackout durations of 0, 1, and 5 sec. Under the fixed-interval 300-sec schedule, the number of interreinforcement responses varied over a wider range than occurred under the fixed-interval 30-sec schedule. The duration of the postreinforcement pause decreased as blackout durations were increased and number of responses decreased on the fixed-interval 300-sec schedule, but pause length did not vary with changes in blackout duration and number of responses for the fixed-interval 30-sec schedule. The differences in the effects of blackout duration and response manipulation on the two fixed-interval schedules were attributed to relatively greater changes in the number of interreinforcement responses for the fixed-interval 300-sec schedule.     

Identification of stuttering in bilingual Lebanese children across two presentation modes

The goals of this study were to investigate whether Lebanese speech-language pathologists (SLPs) are accurate at identifying stuttering in bilingual children, to examine whether the use of video-recordings instead of audio-recordings allows for better analyses, and to explore factors that may affect the SLPs’ judgments. In phase 1, 32 SLPs listened to narrative samples in Lebanese Arabic of 6 children who do not stutter (CWNS) and 2 who stutter (CWS). They were instructed to label each child as stuttering or not, and to explain what motivated their decisions. Afterwards, they were asked to provide background information by means of a questionnaire. In phase 2, they were asked to judge the same speech samples on the basis of video-recordings, and to explain for each child which speech characteristics they relied on to make their decisions. The results showed that misidentification happens frequently, is significantly more likely to happen with CWNS than with CWS, but also varies within these categories. Moreover, the use of video-recordings does not provide more reliable analyses of speech disfluencies, and speech samples’ characteristics and bilingual profile rather than SLPs’ characteristics seem to influence the judgments. Qualitative analyses indicate that, in the current study, misidentification may be driven by neglecting or misinterpreting physical concomitants. In general, the findings indicate that identifying and analyzing speech fluency behaviors remain a challenging perceptual task, which underlies the need for developing consistent methods for training students and clinicians in identifying stuttering, especially in a bilingual context.     

Rapid facial reactions to emotional facial expressions

This study explored how rapidly emotion specific facial muscle reactions were elicited when subjects were exposed to pictures of angry and happy facial expressions. In three separate experiments, it was found that distinctive facial electromyographic reactions, i.e., greater Zygomaticus major muscle activity in response to happy than to angry stimuli and greater Corrugator supercilii muscle activity in response to angry stimuli, were detectable after only 300–400 ms of exposure. These findings demonstrate that facial reactions are quickly elicited, indicating that expressive emotional reactions can be very rapidly manifested and are perhaps controlled by fast operating facial affect programs.     

Gleaning in the field of dual scaling

Some historical background and preliminary technical information are first presented, and then a number of hidden, but important, methodological aspects of dual scaling are illustrated and discussed: normed versus projected weights, the amount of information accounted for by each solution, a perfect solution to the problem of multidimensional unfolding, multidimensional quantification space, graphical display, number-of-option problems, option standardization versus item standardization, and asymmetry of symmetric (dual) scaling. Contrary to the common perception that dual scaling and similar quantification methods are now mathematically transparent, the present study demonstrates how much more needs to be clarified for routine use of the method to arrive at valid conclusions. Data analysis must be carried out in such a way that common sense, intuition and sound logic will prevail.Presidential Address delivered at the Annual Meeting of the Psychometric Society, Banff Centre for Conferences, Banff, Alberta, Canada, June 27–30, 1996. The work has been supported in part by a grant from the Natural Sciences and Engineering Research Council of Canada. I am grateful to Ira Nishisato for his comments, Ingram Olkin and Yoshio Takane for important references, and Liqun Xu for computational help.     

Job stressors,Type A behavior,coping responses,and psychological burnout among teachers

This study examined a research model developed to understand psychological burnout in work settings. Data were collected from 473 teachers and school administrators using questionnaires completed anonymously. Four groups of predictor variables identified in previous research were considered: individual demographic and situational variables, Type A behavior, job Stressors and coping responses. Type A behavior, job Stressors and coping responses were significantly and independently related to levels of psychological burnout.     

Cerebral asymmetry in autonomic conditioning to facial expressions: Sex differences

In the present experiment, sex differences in hemispheric asymmetry during classical conditioning to emotional stimuli are reported. 125 subjects (62 females and 63 males) were shown a slide of a happy face in the right (or left) visual half field (VHF), and simultaneously a slide of an angry face in the left (or right) VHF. Eight groups were formed by the combination of male and female subjects; left and right VHF positions of the angry/happy faces; and the administration/omission of the shock unconditioned stimulus (UCS). Dependent measures were skin conductance responses recorded from both hands. The results during extinction showed a significant larger SCR magnitude to the shock compared to the no-shock groups only for the female subjects. CS position during conditioning was also important in revealing differential responding to either the happy or angry faces. A right hemisphere effect was found for the angry face CS for both the male and female subjects, however with a greater difference for the females.     

On conditioned reinforcing effects of negative discriminative stimuli

Observing responses by pigeons were studied during sessions in which a food key and an observing key were available continuously. A variable-interval schedule and extinction alternated randomly on the food key. In one condition, food-key pecking during extinction decreased reinforcement frequency during the next variable-interval component, and in the other condition such pecking did not affect reinforcement frequency. Observing responses either changed both keylight colors from white to green (S+) or to red (S−) depending on the condition on the food key, or the observing responses never produced the S+ but produced the S− when extinction was in effect on the food key. Observing responses that produced only S− were maintained only when food-key pecking during extinction decreased reinforcement frequency in the subsequent variable-interval component. The red light conformed to conventional definitions of a negative discriminative stimulus, rendering results counter to previous findings that production of S− alone does not maintain observing. Rather than offering support for an informational account of conditioned reinforcement, the results are discussed in terms of a molar analysis to account for how stimuli acquire response-maintaining properties.     

Oral self-administration of pentobarbital by rhesus monkeys: maintenance of behavior by different concurrently available volumes of drug solution.

For 4 rhesus monkeys, mouth-contact responses with either of two brass spouts were reinforced according to fixed-ratio schedules by 0.65-mL liquid deliveries during daily 3-hr sessions. Three experiments were conducted. In each experiment, independent fixed-ratio schedules were concurrently in effect at the two spouts. Following completion of each fixed ratio on a spout, a specified number of liquid deliveries were available from that spout under a continuous-reinforcement schedule. The number of such deliveries available at each spout was manipulated independently. In Experiment 1, a 1-mg/mL pentobarbital solution was simultaneously available with water (the drug vehicle) under concurrent fixed-ratio schedules of 32 responses for 3 subjects and 64 responses for the remaining subject. The number (N) of liquid deliveries that were available after completion of each fixed ratio was varied in the following order: 8, 4, 2, 1, and 8 (retest). For each subject at each condition, drug maintained more responding than water. The number of drug deliveries obtained per session was directly related to the amount of drug available per fixed ratio (i.e., to N), whereas the number of fixed ratios completed per session generally was inversely related to the value of N. In Experiment 2, fixed-ratio size was the same for each subject as in Experiment 1, but deliveries of a 1-mg/mL pentobarbital solution were available at both spouts. The number of drug deliveries available under one fixed-ratio schedule (Ns, the "standard" reinforcer amount) was held at eight, and the number of drug deliveries available under the second schedule (Nc, the "comparison" reinforcer amount) was changed across blocks of six sessions of stable responding in the following order: 1, 2, 4, 8, 4, 2, and 1. The identical series of comparison reinforcer amounts (Nc) was then tested twice more, but with the standard reinforcer (Ns) held first at four and then at two deliveries. Across the three choice series, reinforcing effects were directly related to reinforcer magnitude. In Experiment 3, deliveries of a 1-mg/mL pentobarbital solution again were available at both spouts. However, the two reinforcer amounts were held constant at N = 8 deliveries under one schedule and N = 4 deliveries under the second schedule, and fixed-ratio size was systematically varied. Across the range of fixed-ratio sizes from low to high, the degree to which behavior was better maintained by the larger of the two drug quantities was an inverted U-shaped function of fixed-ratio size.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of observing response requirements to sample and comparison stimuli on the establishment of reject control (sample/S- relations)

The establishment of sample/S- relations (or reject control) during conditional discrimination training (AB, BC) affects transitivity (AC), equivalence (CA) and reflexivity (AA, BB, CC) test outcomes. The present study parametrically evaluated the effects of different observing patterns to comparison stimuli on the establishment of reject control during baseline conditional relation training. A matching-to-sample with observing requirements (MTS-OR) procedure was implemented during AB and BC conditional discrimination training. During training, the participants were required to observe the sample and incorrect comparison on every trial before responding. In addition, the participants were divided into three groups that differed regarding the percentage of training trials on which they were prevented from observing the correct comparison stimuli: 25%, 50%, and 75%. Once the mastery criteria were achieved during training, transitivity (AC), symmetry (BA, CB), equivalence (CA), and reflexivity (AA, BB, CC) tests were conducted with all comparison stimuli visible from the beginning. The results suggest that the number of errors during transitivity, equivalence, and reflexivity tests progressively increased as participants were prevented from observing the correct comparison on a greater number of trials during training. Symmetry test results, however, were not affected by the experimental manipulation. Moreover, the number of participants showing reject-control patterns during tests slightly increased and the number of participants showing select-control patterns decreased as a function of the number of trials on which the participants were prevented from observing the correct comparison. Thus, we suggest that observing patterns during training is a relevant variable that affects equivalence test outcomes.