ON THE EFFECTS OF NONCONTINGENT DELIVERY OF DIFFERING MAGNITUDES OF REINFORCEMENT

We conducted a parametric analysis of response suppression associated with different magnitudes of noncontingent reinforcement (NCR). Participants were 5 adults with severe or profound mental retardation who engaged in a manual response that was reinforced on variable-ratio schedules during baseline. Participants were then exposed to NCR via multielement and reversal designs. The fixed-time schedules were kept constant while the magnitude of the reinforcing stimulus was varied across three levels (low, medium, and high). Results showed that high-magnitude NCR schedules produced large and consistent reductions in response rates, medium-magnitude schedules produced less consistent and smaller reductions, and low-magnitude schedules produced little or no effect on responding. These results suggest that (a) NCR affects responding by altering an establishing operation (i.e., attenuating a deprivation state) rather than through extinction, and (b) magnitude of reinforcement is an important variable in determining the effectiveness of NCR.     

SCHEDULE EFFECTS OF NONCONTINGENT REINFORCEMENT ON ATTENTION-MAINTAINED DESTRUCTIVE BEHAVIOR IN IDENTICAL QUADRUPLETS

Noncontingent reinforcement (NCR), a response-independent schedule for the delivery of reinforcement, has been found to be effective in reducing behavior when the reinforcer delivered is responsible for behavioral maintenance. In this study, dense and lean schedules of response-independent attention were compared to determine whether it is necessary to begin with a dense schedule before fading to a lean schedule, or whether treatment would be as effective using a lean schedule at the outset. The subjects were 5-year-old identical quadruplets diagnosed with mental retardation and pervasive developmental disorder who displayed destructive behavior that was maintained by social attention. NCR was selected partially because it is not very labor intensive and could be implemented by a single mother simultaneously with all 4 children. Using a combination multielement and multiple baseline design, it was found that (a) a dense schedule of response-independent reinforcement (i.e., fixed-time 10 s) resulted in immediate and dramatic reductions in destructive behavior with no evidence of an extinction burst, and (b) an equivalent reduction in destructive behavior was achieved with a lean schedule of response-independent reinforcement (fixed-time 5 min) only after a systematic fading procedure was implemented. The findings suggest that the effectiveness of NCR may be dependent on the use of a dense schedule initially, and that systematic fading can increase the effectiveness of a lean schedule.     

THE RELATION OF FOOD QUANTITY TO RUMINATION BEHAVIOR

Preliminary work suggested that the quantity of food ingested by retarded individuals who usually ruminated following meals was related to the frequency and duration of ruminating responses. This possible relation was experimentally examined by systematically varying food quantity from regular portions to satiation levels for three retarded individuals who exhibited high levels of ruminating. A clear functional relation of food quantity to ruminating emerged, with satiation procedures producing rapid and large decreases in the relatively high frequencies and durations of ruminating characteristic of baseline food quantity conditions.     

Session duration and the VI response function: Within-session prospective and retrospective effects

Two experiments examined the effects of session duration on responding during simple variable-interval schedules. In Experiment 1, rats were exposed to a series of simple variable-interval schedules differing in both session duration (10 min or 30 min) and scheduled reinforcement rate (7.5 s, 15 s, 30 s, and 480 s). The functions relating response rate to reinforcement rate were predominantly monotonic for the short (10-min) sessions but were predominantly bitonic for the long (30-min) sessions, when data from the entire session were considered. Examination of responding within sessions suggested that differences in the whole-session data were produced by a combination of prospective processes (i.e., processes based on events scheduled to occur later in the session) and retrospective processes (i.e., processes based on events that had already occurred in the session). In Experiment 2, rats were exposed to a modified discrimination procedure in which pellet flavor (standard or banana) predicted session duration (10 min or 30 min). All rats came to respond faster during the short (10-min) sessions than during the first 10 min of the long sessions. As in Experiment 1, the results seemed to reflect the simultaneous operation of both prospective and retrospective processes. The results shed light on the recent controversy over the form of the variable-interval response function by identifying one variable (session duration) and two types of processes (prospective and retrospective) that influence responding on these schedules.     

内隐学习“三高”特征的实验研究

本研究在社会认知的人物特征识别范畴内,探讨在高强度练习和准确反馈条件下,内隐学习的高选择力、高潜力以及高密度贮存三大特征。实验采用一种测量内隐和外显学习的新方法,要求被试学会把像片按其组合特征分类。这些特征包括人物姿势的正侧面(显著维度特征),人物容貌的美丑(非显著维度特征)。结果表明:(1)非显著特征的学习,内隐被试表现出更大且显著的底层规则的迁移,比外显被试具有更高的选择力。(2)内隐被试表现出高潜力的内隐知识。(3)信息论处理揭示了内隐知识传递和贮存的高密性和高效性。     

ESTABLISHING OPERATIONS AND REINFORCEMENT EFFECTS

Positive reinforcement procedures have had a major impact on educational programs for the developmentally disabled; nevertheless, variation in reinforcer effectiveness both within and across individuals is a common phenomenon. This study examined one class of variables—establishing operations—that might influence the effectiveness of reinforcers. Five developmentally disabled adult males participated. Responding on one of two motor tasks—switch closure or block placement—was assessed during baseline, satiation, and deprivation conditions with respect to three classes of consequences: small food items, music, and social praise. Deprivation and satiation conditions were constructed so as not to alter significantly the normal course of events in a subject's day. For example, food deprivation entailed scheduling sessions just prior to a subject's regular lunch, and social deprivation involved limiting a subject's access to social interaction for 15 minutes, during which time the subject had access to an assortment of other activities. Results showed that each stimulus class functioned as reinforcement with different degrees of effectiveness during satiation versus deprivation conditions. These results are discussed in light of previous research on enhancement of reinforcer efficacy as well as the assessment and identification of functional reinforcers, and implications are presented for future research and client habilitation.     

Reducing the Biological and Psychological Toxicity of Poverty-related Stress: Initial Efficacy of the BaSICS Intervention for Early Adolescents

This proof-of-concept study tests the initial efficacy of the Building a Strong Identity and Coping Skills (BaSICS) intervention, a selective prevention of internalizing problems program for early adolescents exposed to high levels of poverty-related stress. Eighty-four early adolescents (M_age = 11.36 years) residing in very low-income neighborhoods were randomized to receive the 16-session intervention (n = 44) or to an assessment-only control condition (n = 40). BaSICS teaches coping skills, social identity development, and collective social action to empower youth with the ability to connect with members of their communities and cope with poverty-related stress in positive and collaborative ways. Pretest–posttest analyses showed that intervention adolescents acquired problem-solving and cognitive-restructuring skills and reduced their reliance on avoidant coping. In addition, HPA reactivity was significantly reduced in the intervention youth, but not controls. Finally, intervention youth's internalizing and somatic symptoms as reported by both youth and their parents, showed significant reductions over time, whereas control youth had no such changes. Results provide strong support for this approach to strength-building and symptom reduction in a population of early adolescents exposed to poverty-related stress.     

The role of attentional slippage in Stroop dilution

The present study examined the cognitive locus of Stroop dilution using a psychological refractory period (PRP) paradigm. Participants were asked to perform a tone discrimination task via a bimanual keypress response and a modified Stroop task via a vocal response serially as Task 1 and Task 2, respectively. In Task 2, a neutral word was added on half of the trials and no neutral word on the other half of the trials to observe the Stroop dilution effect. The amount of Stroop dilution, as well as the Stroop effect, was relatively constant across different stimulus-onset asynchronies (SOAs), which implies that Stroop dilution occurs due to the competition between a neutral word and a color word after a target color bar is selected to be processed further. These results indicate that focused attention plays an important role in the modulation of Stroop interference by the presence of a neutral word.     

The Development of Selective Attention in Children With Attention Deficit Hyperactivity Disorder

The influence of age on a selective attention task was studied in a sample of children with and without Attention Deficit Hyperactivity Disorder (ADHD). The impact of methylphenidate (MPH) treatment on selective attention was also investigated in the children with ADHD. Two age groups of children with ADHD and two age groups of control children were tested using a timed computer task. The task consisted of identifying visual target stimuli under various distracter conditions. Distracters varied on the basis of modality (i.e., visual, auditory, or both) and task relevance (i.e., meaningful or irrelevant). Reaction times and accuracy were measured. Children with ADHD were less efficient on the selective attention task than were children without ADHD, and older children were more efficient than younger children in both groups. Children without ADHD were influenced more by the nature of distracters than were children with ADHD. For children with ADHD, MPH improved performance overall.     

Attentive processing of threat and adult attachment: a dot-probe study

We examined selective attention to threat stimuli as a function of individual differences in adult attachment. Participants completed a dot-probe task in which a general threat word, attachment-related threat word, general positive or attachment-related positive word was presented together with a neutral word. Results showed that attachment anxiety and avoidance were associated with an attentional bias away from attachment threat words. This attentional avoidance effect was best predicted by the interaction between attachment anxiety and avoidance and not by their unique main effects. The findings are discussed in terms of attachment theory and its relation to attentional biases observed in psychopathology.