Bootstrapping Processes in the Development of Students' Commonsense Matter Theories: Using Analogical Mappings,Thought Experiments,and Learning to Measure to Promote Conceptual Restructuring

This study explores whether the development of students' understanding of matter as something that occupies space and has weight involves conceptual change and restructuring rather than only simple belief revision. Based on an analysis of how the concepts in students' initial matter theory (henceforth MT1) may differ from the concepts in the matter theory that is a target of middle school instruction (MT2), I propose ways that concepts in a given theory cohere with each other and identify the sources of the new ideas in MT2 and the learning processes by which those new ideas can be acquired. I test implications of these analyses by designing a curriculum unit that exploits these learning mechanisms, by using the curriculum with 4 classes of eighth-grade Earth Science students, and by assessing 42 students' thinking about matter, object size, and weight (via individual interviews and written tests) before and after the teaching unit. Consistent with the hypothesis of conceptual restructuring, the data not only show coherencies in students' thinking about matter, size, and weight before and after teaching, but also coordinated patterns of change. The implications for the design of science instruction are discussed.     

Does the "eyes lead the hand" principle apply to reach-to-grasp movements evoked by unexpected balance perturbations?

A fundamental principle that has emerged from studies of natural gaze behavior is that goal-directed arm movements are typically guided by a saccade to the target. In this study, we evaluated a hypothesis that this principle does not apply to rapid reach-to-grasp movements evoked by sudden unexpected balance perturbations. These perturbations involved forward translation of a large (2 × 6 m) motion platform configured to simulate a “real-life” environment. Subjects performed a common “daily-life” visuo-cognitive task (find a telephone and make a call) that required walking to the end of the platform, which was triggered to move as they approached a handrail mounted alongside the travel path. A deception was used to ensure that the perturbation was truly unexpected. Eleven of 18 healthy young-adult subjects (age 22-30) reached to grasp or touch the rail in response to the balance perturbation. In support of the hypothesis, none of these arm reactions was guided by concurrent visual fixation of the handrail. Seven of the 11 looked at the rail upon first entering the environment, and hence may have used “stored” central-field information about the handrail location to guide the subsequent arm reaction. However, the other four subjects never looked directly at the rail, indicating a complete reliance on peripheral vision. These findings add to previous evidence of distinctions in the CNS control of volitional and perturbation-evoked arm movements. Future studies will determine whether similar visuo-motor behavior occurs when the available handhold is smaller or when subjects are not engaged in a concurrent visuo-cognitive task.     

Community norms about suppression of AIDS-related prejudice and perceptions of stigma by people with HIV or AIDS

We investigated the relationship between community motivations to control AIDS-related prejudice and the experience of stigma by community members with HIV or AIDS, using self-reports from 203 New England residents with HIV or AIDS and 2,444 randomly selected residents of the same New England communities. Multilevel regression analyses revealed that the disclosure concerns of participants with HIV or AIDS were lower in communities where residents were motivated by personal values to control AIDS-related prejudice, and were higher in communities where residents were motivated by social pressure to control AIDS-related prejudice. Reported experiences with discrimination and exclusion were unrelated to community motivations. The results of our study suggest that external and internal pressures to control prejudice shape the experience of stigmatization.     

Predicting self-injury in BPD: an investigation of the experiential avoidance model

This study investigated the contribution of indices of experiential avoidance to prediction of frequency and lethality of self-injurious behaviour (SIB) in a female BPD sample (N = 71) with high levels of SIB and histories of poor treatment outcomes. The experiential avoidance model (EAM) tested included motivations for SIB, coping style and DSM-IV Avoidant PD criteria. Distinct findings for suicidal and non-suicidal SIB were noted. In partial support of the model, motivations related to relief from negative emotions positively predicted frequency of non-suicidal, but not suicidal, SIB. Avoidant PD traits predicted a pattern of more frequent, less risky non-suicidal SIB. However, reliance on avoidant coping strategies predicted lethality but not frequency of SIB, while self-blaming coping and SIB motivations related to a desire to influence others predicted frequency of non-suicidal SIB. Results suggest the need for investigation of a more complex model of the antecedents and functions of SIB that includes the contribution of Avoidant PD traits.     

Dimensionality of the Obsessive Beliefs Questionnaire (OBQ)

The Obsessive Beliefs Questionnaire (OBQ) is a self-report measure in development by the Obsessive Compulsive Cognitions Working Group (OCCWG), who studies cognitive aspects of obsessive–compulsive disorder (OCD). The aim of this paper was to evaluate the dimensionality of the OBQ in students (n = 995). Two models were tested in a confirmatory framework, corresponding to the OCCWG's (a) original six subscales (87 items), and (b) more recent three subscales (44 items). Both models fit the present data poorly; thus, an exploratory analysis was undertaken. Results revealed one large factor that is relevant, but not unique, to OCD, and three factors that are conceptually consistent with the OCCWG's recent three: (a) distorted beliefs about one's own thoughts, (b) perfectionism, and (c) inflated responsibility. Convergent and divergent validity analyses of the present OBQ factors generally supported the preceding interpretations. Readers are referred to the work of the OCCWG for revisions to the OBQ.     

Making the sour sweet? Upcoming food-pellet reinforcement produces positive induction when rats press a lever for unsweetened lemon juice

Research has suggested that rats increase their response rate for a low-valued reinforcer when a high-valued reinforcer will soon be available (i.e., positive induction) because the value of the low-valued substance has increased. The present study tested if such a procedure could be used to increase rats’ responding for a non-reinforcing food. Rats pressed a lever for unsweetened lemon juice in the first half of a 50-min session and, in treatment conditions, for food pellets in the second half. Experiment 1 demonstrated that rates of responding for the lemon juice generally varied directly with the upcoming rate of food-pellet reinforcement and that responding in lemon juice-only sessions did not differ significantly from that observed during extinction. Experiment 2 demonstrated that rats consumed more lemon juice following a condition in which they were displaying positive induction than following a condition in which they only responded for lemon juice. The present results are consistent with the increase in value account of positive induction. More importantly, they may indicate that certain environmental conditions can increase food-directed behavior for a non-reinforcing food, a finding which may have implications for our understanding of eating behavior and dysfunctions (e.g., overeating).