Interactions in multiple schedules: the role of the stimulus-reinforcer contingency

In Experiments I and II, pigeons were exposed to single-key multiple schedules of response-independent and -dependent food presentation. Components were correlated with different keylights. When the rate of food presentation in the first component exceeded that in the second component, the local rate of key pecking was relatively high at onset of the first component. Overall rate in that component varied inversely with component duration and the rate of food presentation in the second component. When responding was maintained in the second component, the local rate of key pecking was relatively low at onset of that component. Overall rate in the second component varied directly with component duration and the rate of food presentation in that component. In Experiment III, pigeons were exposed to a two-key multiple schedule. Pecks on a constantly illuminated key produced food. Components were correlated with the color of a second key on which pecks had no scheduled consequences. The effects of component duration and rate of food presentation under the single-key response-dependent schedule were synthesized by combining response rates on each concurrently available key under the two-key procedure. The results support an account of multiple-schedule interactions in terms of the joint influence on responding of stimulus-reinforcer and response-reinforcer contingencies.     

Alternative response training, differential reinforcement of other behavior, and extinction in squirrel monkeys (Saimiri sciureus)

In Experiment I, (a) extinction, (b) extinction plus reinforcement of a discrete alternative response, and (c) differential reinforcement of other behavior were each correlated with a different stimulus in a three-component multiple schedule. The alternative-response procedure more rapidly and completely suppressed behavior than did differential reinforcement of other behavior. Differential reinforcement of other behavior was slightly more effective than extinction alone. In Experiment II, reinforcement of specific alternative behavior during extinction and differential reinforcement of other behavior were used in two components, while one component continued to provide reinforcement for the original response. Once again, the alternative-response procedure was most effective in reducing responding as long as it remained in effect. However, the responding partially recovered when reinforcement for competing behavior was discontinued. In general, responding was less readily reduced by differential reinforcement of other behavior than by the specific alternative-response procedure.     

The impacts of ignoring individual mobility across clusters in estimating a piecewise growth model

A three-level piecewise growth model (3L-PGM) can be used to break up nonlinear growth into multiple components, providing the opportunity to examine potential sources of variation in individual and contextual growth within different segments of the model. The conventional 3L-PGM assumes that the data are strictly hierarchical in nature, where measurement occasions (level 1) are nested within individuals (level 2) who are members of a single cluster (level 3). However, in longitudinal research, it is sometimes difficult for data structures to remain purely clustered during a study, such as when some students change classrooms or schools over time. One resulting data structure in this situation is known as a multiple membership structure, where some lower-level units are members of more than one higher-level unit. The new multiple membership PGM (MM-PGM) extends the 3L-PGM to handle multiple membership data structures frequently found in the social sciences. This study sought to examine the consequences of ignoring individual mobility across clusters when estimating a 3L-PGM in comparison to estimating a MM-PGM. MM-PGM estimates were less biased (especially in the cluster-level coefficient estimates), although we found substantial bias in cluster-level variance components across some conditions for both models.     

Multiple sclerosis,emotion perception and social functioning

People with multiple sclerosis (MS) can experience problems in interpreting others’ emotions from faces or voices. However, to date little is known about whether difficulties in emotion perception in MS are related to broader aspects of social functioning. Also, there are few studies reporting the effect of MS on more ecologically valid assessments of emotion perception using multimodal videos. The current study looks at (1) the effect of MS on perceiving emotions from faces, voices and multimodal videos; (2) the possible role of slowed processing and executive dysfunction in emotion perception problems in MS and (3) the relationship between emotion perception and broader social functioning in MS. 53 people with MS and 31 healthy controls completed tasks of emotion perception and cognition, and assessed their levels of social support and social participation. Participants with MS performed worse than demographically matched controls on all measures of emotion perception. Emotion perception performance was related to cognitive measures in those with MS. Also, significant associations were found between emotion perception difficulties in MS and poorer social function. In particular, people with MS who had poorer emotion perception also reported lower levels of social support from their friends, and regression analysis showed that this prediction was maintained even when disease severity and cognitive function were taken into account. These results show that problems with emotion perception in MS extend to more realistic tasks and may predict key aspects of social functioning.     

留守初中生同伴侵害与攻击性的关系:链式多重中介模型

为探究留守初中生同伴侵害与攻击性的关系机制,通过构建链式多重中介模型,考察歧视知觉、孤独感和心理韧性在二者关系中的多重中介效应。采用问卷调查法对519名留守初中生进行调查,结果显示：（1）留守初中生同伴侵害的发生率为96.3%,具有普遍性;（2）留守初中生同伴侵害、歧视知觉、孤独感、心理韧性与攻击性之间均呈显著相关;（3）留守初中生的歧视知觉、孤独感和心理韧性在其同伴侵害与攻击性的关系中具有链式多重中介作用;（4）同伴侵害与攻击性关系模型具有一定稳定性,同时在是否留守及单亲与双亲外出留守初中生群体中存在显著差异。研究结果揭示了同伴侵害与攻击性的关系机制,可为探索留守初中生不良同伴关系的教育策略提供参考。     

Assessment and treatment of elopement maintained by chase

Elopement can have serious or fatal consequences associated with leaving the presence of an adult or getting lost (e.g., traffic injury and drowning). Given the dangers associated with elopement, caregivers are likely to chase after their child when elopement occurs. Like other forms of attention that follow problem behavior, chasing and retrieving the child may serve as a reinforcer and therefore maintain elopement. However, no study to date has evaluated whether elopement is sensitive to positive reinforcement in the form of chase. We evaluated the effects of chase on elopement with an 8‐year old boy diagnosed with autism. Elopement was maintained, at least in part, by chase. We then conducted a treatment evaluation in which we tested the effects of various antecedent‐ and consequence‐based treatment components within a multiple schedule.     

Statistical learning of multiple speech streams: A challenge for monolingual infants

Language acquisition depends on the ability to detect and track the distributional properties of speech. Successful acquisition also necessitates detecting changes in those properties, which can occur when the learner encounters different speakers, topics, dialects, or languages. When encountering multiple speech streams with different underlying statistics but overlapping features, how do infants keep track of the properties of each speech stream separately? In four experiments, we tested whether 8‐month‐old monolingual infants (N = 144) can track the underlying statistics of two artificial speech streams that share a portion of their syllables. We first presented each stream individually. We then presented the two speech streams in sequence, without contextual cues signaling the different speech streams, and subsequently added pitch and accent cues to help learners track each stream separately. The results reveal that monolingual infants experience difficulty tracking the statistical regularities in two speech streams presented sequentially, even when provided with contextual cues intended to facilitate separation of the speech streams. We discuss the implications of our findings for understanding how infants learn and separate the input when confronted with multiple statistical structures.     

Progressive-ratio schedules: effects of later schedule requirements on earlier performances

Four rats were studied with variants of a progressive-ratio schedule with a step size of 6 in which different terminal components followed completion of the 20th ratio: (a) a reversal of the progression, (b) a fixed-ratio 6 schedule, or (c) extinction. Responding in the progressive-ratio components of these schedules was compared to performances under conventional progressive-ratio baselines. Under baseline conditions, postreinforcement pauses increased exponentially as a function of increasing ratio size, whereas running rates showed modest declines. The procedure of linking the progressive-ratio schedule to the reversed progression or to the fixed-ratio component resulted in decreased pausing. Linking the progressive-ratio schedule to the extinction component had the opposite effect, that of producing weakened progressive-ratio performances as evidenced by increased pausing. Subjects whose responses were reinforced on half of the ratios also showed exponential increases; however, pauses were substantially shorter following ratios on which the reinforcer was omitted. The results suggested that progressive-ratio pausing reflects the influence of remote as well as local contingencies.     

An evaluation of a brief multiple-stimulus preference assessment with adolescents with emotional-behavioral disorders in an educational setting

Brief multiple-stimulus-without-replacement (MSWO) preference assessments were conducted with 3 adolescent boys with emotional-behavioral disorders in the context of their public school educational program. The reinforcing effects of stimuli identified as high, medium, and low preference were then evaluated using an alternating treatments design in which, following an initial baseline, stimuli were delivered contingent on on-task behavior. High-preference stimuli produced the highest percentages of on-task behavior for all 3 participants.