Using progressive ratio schedules to evaluate tokens as generalized conditioned reinforcers

The properties of operant reinforcers are dynamic and dependent on a number of variables, such as schedule and effort. There has been sparse research on the generalized conditioned properties of token reinforcement. We evaluated leisure items, edible items, and tokens using a progressive ratio schedule with three children with diagnoses of ASD and developmental delays. The highest break points occurred during the token reinforcement condition for two out of three participants, but response rates tended to be higher with edibles. We then evaluated the effects of presession access to edibles on the break points of edible items and tokens with two participants. Break points decreased only in the edible reinforcement condition, and the participants chose to work for leisure items rather than edibles when presession access to edibles was in place. These findings suggest that the tokens functioned as generalized conditioned reinforcers.     

Projection of the Magnocellular Red Nucleus to the Region of the Accessory Abducens Nucleus in the Rabbit

The projection of the magnocellular red nucleus (RNm) to the region of the accessory abducens nucleus (AABD) was traced in rabbit using the bidirectional tracer wheat germ agglutinin-horseradish peroxidase (WGA-HRP). In one set of animals, recordings of antidromic responses from RNm neurons elicited by electrical stimulation of the rubrospinal tract were used to localize injections of WGA-HRP for orthograde labeling of RNm terminals. In a different set of animals, horseradish peroxidase was injected into the retractor bulbi muscle to retrogradely label motoneurons of the AABD. The positions of RNm fibers and terminals were examined and compared to the locations and distribution of AABD cell bodies and labeled dendrites. Analyses revealed that along the entire rostrocaudal extent of the AABD, RNm efferents terminate primarily lateral to, or in the lateral aspects of, labeled motoneurons. For the rostral AABD, RNm efferents terminate only lateral to the nucleus. Although the terminals are not positioned to contact cell bodies of the AABD, they could overlap with dendrites that extend in the lateral direction. RNm efferents terminate more extensively within the posterior AABD, overlapping within both dendritic and cell body regions of the nucleus. Even in this posterior region, however, RNm efferents were distributed primarily over the lateral half of the nucleus. These data show that RNm can monosynaptically influence the AABD, through primarily its lateral and posterior aspects. Our findings also show that a major target of RNm efferents is the reticular cell population located lateral to the AABD, suggesting that the RNm also may affect AABD motoneuronal output indirectly through its projection to reticular cells.     

顿悟问题解决过程中抑制解除理论有效性的实验研究

本研究以Puzzle任务为材料,对135名高二学生特定线索下的操作水平进行测查,结果表明：（1）表征的抑制解除理论对顿悟问题解决的机制具有一定的解释效力,表现为总体上经历了高操作失败次数的被试在线索敏感性上明显高于未经历操作失败次数的被试。（2）而被试在特定阶段的操作水平未出现朝向解决目标的线性增长而是出现停滞的现象证明了问题的表征复杂性对抑制解除的过程存在制约作用,使其宏观上表现为渐进-停滞-跃升的变化模式。     

ON THE CORRESPONDENCE BETWEEN PREFERENCE ASSESSMENT OUTCOMES AND PROGRESSIVE‐RATIO SCHEDULE ASSESSMENTS OF STIMULUS VALUE

The current study examined whether stimuli of different preference levels would be associated with different amounts of work maintained by the stimuli, as determined through progressive‐ratio schedule break points. Using a paired‐choice preference assessment, stimuli were classified as high, moderate, or low preference for 4 individuals with developmental disabilities. The stimuli were then tested three times each using a progressive‐ratio schedule (step size of 1; the break‐point criterion was 1 min). In 10 of 12 possible comparisons, higher preference stimuli produced larger break points than did lower preference stimuli.     

INTRODUCTION: RETHINKING PHILOSOPHICAL PRESUMPTIONS IN LIGHT OF COGNITIVE DISABILITY

Abstract: This Introduction to the collection of essays surveys the philosophical literature to date with respect to five central questions: justice, care, agency, metaphilosophical issues regarding the language and representation of cognitive disability, and personhood. These themes are discussed in relation to three specific conditions: intellectual and developmental disabilities, Alzheimer's disease, and autism, though the issues raised are relevant to a broad range of cognitive disabilities. The Introduction offers a brief historical overview of the treatment cognitive disability has received from philosophers, and explains the specific challenges that cognitive disability poses to philosophy. In briefly summarizing the essays in the collection, it highlights the distinctive contributions the collection makes to ethics, political philosophy, bioethics, and the philosophy of disability. We hope that the richness of the topics explored by these essays will be a spur to further investigation.     

CORRESPONDENCE BETWEEN SINGLE VERSUS DAILY PREFERENCE ASSESSMENT OUTCOMES AND REINFORCER EFFICACY UNDER PROGRESSIVE‐RATIO SCHEDULES

Research has suggested that a daily multiple‐stimulus‐without‐replacement (MSWO) preference assessment may be more sensitive to changes in preference than other assessment formats, thereby resulting in greater correspondence with reinforcer efficacy over time ( DeLeon et al., 2001 ). However, most prior studies have measured reinforcer efficacy using rate of responding under single‐operant arrangements and dense schedules or under concurrent‐operants arrangements. An alternative measure of reinforcer efficacy involves the evaluation of responding under progressive‐ratio (PR) schedules. In the present study, 7 participants were given a single paired‐stimulus (PS) preference assessment followed by daily MSWO preference assessments. After each daily MSWO, participants responded for each stimulus on a PR schedule. The correspondence between break points and preferences, as assessed by the 2 assessment formats, was examined. Results demonstrated that both preference assessments did equally well at predicting reinforcer efficacy, although the PS more consistently identified the most effective reinforcer.     

Interpersonal Problems,Mindfulness, and Therapy Outcome in an Acceptance-Based Behavior Therapy for Generalized Anxiety Disorder

Objective: To better understand the role interpersonal problems play in response to two treatments for generalized anxiety disorder (GAD); an acceptance-based behavior therapy (ABBT) and applied relaxation (AR), and to examine how the development of mindfulness may be related to change in interpersonal problems over treatment and at follow-up. Method: Eighty-one individuals diagnosed with GAD (65.4% female, 80.2% identified as white, average age 32.92) were randomized to receive 16 sessions of either ABBT or AR. GAD severity, interpersonal problems, and mindfulness were measured at pre-treatment, post-treatment, 6-month follow-up, and 12-month follow-up. Results: Mixed effect regression models did not reveal any significant effects of pre-treatment interpersonal problems on GAD severity over treatment. After controlling for post-treatment GAD severity, remaining post-treatment interpersonal problems predicted 6- but not 12-month GAD severity. Participants in both conditions experienced a large decrease in interpersonal problems over treatment. Increases in mindfulness over treatment and through follow-up were associated with decreases in interpersonal problems, even when accounting for reductions in overall GAD severity. Conclusions: Interpersonal problems may be an important target of treatment in GAD, even if pre-treatment interpersonal problems are not predictive of outcome. Developing mindfulness in individuals with GAD may help ameliorate interpersonal difficulties among this population.     

Simulating the Impact During Human Jumping by Means of a 4-Degrees-of-Freedom Model With Time-Dependent Properties

The authors simulated the vertical movements of a jumper and the force time courses by means of a 4-degrees-of-freedom model consisting of 4 masses, springs, and dampers. Of the motions simulated, only that of the mass imitating the trunk corresponded to the measured data. The best fit to the measured force curves were obtained in the simulation in which time-dependent model parameters were used. From the results, the authors concluded that at the beginning of the landing, a jumper behaves like a 2-mass model in which the leg segments (thighs, shanks, and feet) effectively combine into 1 mass. After approximately 60 ms, the connections between the leg segments become more compliant and the jumper behaves like a 4-mass model with a soft coupling between the leg segments. The process is equivalent to an increase of the degrees of freedom of the movements. At the end of the ground contact phase during hopping, the jumper has to contract the muscles in order to reach the envisaged jump height. In the model, that contraction could not be satisfactorily simulated.     

The Link Between Cerebellar Dominance and Skilled Hand Performance in 8–10-Year-Old Right-Handed Children

A focus of attention on the step-by-step control of a skill has been shown to be detrimental to experts' performance but to have no significant effect on novices' performance (e.g., S. L. Beilock, T. H. Carr, C. MacMahon, &; J. L. Starkes, 2002), contrary to the results of manipulations of the direction of attentional focus (e.g., G. Wulf, M. Hös, &; W. Prinz, 1998). In previous studies, researchers have not separated the focus of attention from the nature of the instruction provided or the skill level of the participants. In the present experiment, 10 skilled and 10 less skilled soccer players dribbled a ball after receiving instructions directing attention to an internal, skill-relevant feature (foot); an internal, skill-irrelevant feature (arm); or a skill-irrelevant task (word-monitoring). Performance was evaluated in relation to a no-attentional-focus control condition. For skilled performers, an internal focus on the arms and feet interfered with performance. For less skilled performers, an internal, yet skill-relevant, focus of attention (foot) did not degrade performance, whereas attention to the arms and word monitoring had a detrimental effect. No significant differences were observed across the three attentional manipulations when the skilled performers used the nondominant foot. The results generally supported the deautomization of skills hypothesis.