Age trends in stimulus overselectivity

Stimulus overselectivity refers to the phenomenon whereby stimulus control over behavior is exerted only by a limited subset of the total number of stimuli present during discrimination learning. It often is displayed by individuals with autistic spectrum disorders or learning disabilities, but is not exclusive to those groups. The present studies investigated the impact of aging on stimulus control and overselectivity. Three age groups--18-22, 47-55, and 70-80 year olds-were studied in two experiments. All participants were trained on a simple discrimination task, randomly assigned to one of two conditions (either with or without a distractor task), and then tested for the emergence of overselectivity (Experiment 1). In Experiment 2 responding controlled by the overselected stimulus elements was reduced by introducing a verbal punisher. In subsequent tests, control of behavior by the previously underselected elements from Experiment 1 was enhanced across the two younger age groups but not the oldest group of participants. The results are discussed in relation to the attention-deficit and overshadowing accounts of overselectivity.     

Human sensitivity to reinforcement feedback functions

Two experiments investigated human sensitivity to the temporally extended aspects of reinforcement schedules. Experiment 1 investigated human sensitivity to the extended and local aspects of three reinforcement schedules: variable ratio (VR), variable interval (VI), and variable-interval-plus-linear-feedback (VI+) schedules. Experiment 2 investigated this sensitivity on two reinforcement schedules: VI and VI+ schedules. In both experiments, there was evidence of sensitivity to the temporally extended aspects of the schedule: There were differences between the response rate on the VI+ and yoked-VI schedules, but no statistical difference in rates of response between the VR and VI+ schedules. The VI+ versus VI difference was much more pronounced when a lower response force needed to depress a lever was used. These results suggest that human subjects do show some sensitivity to temporally extended aspects of schedules of reinforcement.     

Rats' performance on variable-interval schedules with a linear feedback loop between response rate and reinforcement rate

Three experiments investigated whether rats are sensitive to the molar properties of a variable-interval (VI) schedule with a positive relation between response rate and reinforcement rate (i.e., a VI+ schedule). In Experiment 1, rats responded faster on a variable ratio (VR) schedule than on a VI+ schedule with an equivalent feedback function. Reinforced interresponse times (IRTs) were shorter on the VR as compared to the VI+ schedule. In Experiments 2 and 3, there was no systematic difference in response rates maintained by a VI+ schedule and a VI schedule yoked in terms of reinforcement rate. This was found both when the yoking procedure was between-subject (Experiment 2) and within-subject (Experiment 3). Mean reinforced IRTs were similar on both the VI+ and yoked VI schedules, but these values were more variable on the VI+ schedule. These results provided no evidence that rats are sensitive to the feedback function relating response rate to reinforcement rate on a VI+ schedule.     

Holistic versus analytic processing: Evidence for a different approach to processing of Chinese at the word and character levels in Chinese children

Among 30 Hong Kong Chinese fourth graders, sensitivities to character and word constructions were examined in judgment tasks at each level. There were three conditions across both tasks: the real condition, consisting of either actual two-character compound Chinese words or real Chinese compound characters; the reversed condition, with either the order of the two morphemes in the word or the order of the semantic and phonetic radicals in the character reversed; and the random condition, with either two morphemes randomly combined to create arbitrary nonwords or a semantic radical and a phonetic radical randomly combined using correct orthographic rules to create noncharacters. On the word level, children performed worst in the reversed condition and best with real words, whereas on the character level, children performed worst in the random condition and best in the reversed condition. Findings imply a holistic tendency toward word-level processing and an analytic approach to character-level processing in these Chinese children.     

Determining Relationships Between Physical Health and Spiritual Experience,Religious Practices,and Congregational Support in a Heterogeneous Medical Sample

Previous research indicates that increased religiosity/spirituality is related to better health, but the specific nature of these relationships is unclear. The purpose of this study was to determine the relationships between physical health and spiritual belief, religious practices, and congregational support using the Brief Multidimensional Measure of Religiousness/Spirituality and the Medical Outcomes Scale Shortform-36. A total of 168 participants were surveyed with the following medical disorders: Cancer, Spinal Cord Injury, Traumatic Brain Injury, and Stroke, plus a healthy sample from a primary care setting. The results show that individuals with chronic medical conditions do not automatically turn to religious and spiritual resources following onset of their disorder. Physical health is positively related to frequency of attendance at religious services, which may be related to better health leading to increased ability to attend services. In addition, spiritual belief in a loving, higher power, and a positive worldview are associated with better health, consistent with psychoneuroimmunological models of health. Practical implications for health care providers are discussed.     

Perceiving Violence: The Influence of Motivational Status and Environmental Setting

Previous studies examining perceptions of violence within a public house context have shown that the presence of door control (bouncers), interior tidiness, and the actions of the victim play an important role in shaping judgments of the aggressor and the victim (Lawrence & Leather, 1999; Leather & Lawrence, 1995). However, the extent to which individuals belonging to the same group as the victim make similar patterns of judgments to those recruited from a different group has not been investigated. This paper reports the findings of a study in which the perceptions of 80 licensees (same group as victim) and 80 undergraduate students (different group from victim) are compared after exposure to an account of a violent incident. Also manipulated were environmental variables (presence of door control and interior tidiness) and the actions of the victim. Results support the JWH, whereby the victim is blamed more by those from the same group than by those from a different group. Results are discussed in light of defensive attributions and the JWH and highlight the importance of taking environmental information into account in studies of social cognition.     

Survey on Using Ethical Principles in Environmental Field Research with Place-Based Communities

Science and Engineering Ethics - Researchers of the Northeast Ethics Education Partnership (NEEP) at Brown University sought to improve an understanding of the ethical challenges of field...