Coordination changes in the early stages of learning to cascade juggle

The experiment was setup to examine the coordination changes in assembling the movement form of 3-ball cascade juggling. Eight adult participants learned to juggle over 4 weeks of practice. Juggling scores were recorded at each session and performance was videotaped at eight selected sessions for purposes of movement analysis. Once the basic spatial and temporal constraints on cascade juggling were satisfied, and the figure-8 juggling mode was established, temporal modulations of the relative motions of the hands were emphasized. All participants learned to juggle and the increase over practice in the number of consecutive balls caught was best fit with a power law. The non-proportional rate of performance increment was consistent with the qualitative changes in the form of the hand and ball movement kinematics that occurred over practice.     

A neuropsychiatric developmental model of serial homicidal behavior

Serial sexual homicide has been the object of intensive study from forensic psychiatric, criminological, developmental, and sociological perspectives. In contradistinction to these approaches, neuropsychiatric concepts and methods have received relatively little attention in this area. In this article we adopt a neuropsychiatric developmental perspective and undertake a review of the psychiatric literature on violence and autism spectrum disorders. Our analysis of this literature suggests the presence of an association between autism spectrum psychopathology and serial homicidal behavior. Recommendations for further research to help clarify the nature of this association are briefly discussed.     

Trauma histories and attachment styles of members of the International Society for Traumatic Stress Studies

The study is focused on the training, demographics, perceived emotional and physical health, past traumatic experience histories, and attachment styles of mental health professionals in the field of trauma (members of the International Society for Traumatic Stress Studies). While the data set is limited by a low response rate of 20%, the uniqueness of the sample and distinctive themes yield insight into the experience of trauma and its association with attachment style.     

Learning to optimize speed, accuracy, and energy expenditure: a framework for understanding speed-accuracy relations in goal-directed aiming

Over the last century, investigators have developed a number of models to explain the relation between speed and accuracy in target-directed manual aiming. The models vary in the extent to which they stress the importance of feedforward processes and the online use of sensory information (see D. Elliott, W. F. Helsen, & R. Chua, 2001, for a recent review). A common feature of those models is that the role of practice in optimizing speed, accuracy, and energy expenditure in goal-directed aiming is either ignored or minimized. The authors present a theoretical framework for understanding speed-accuracy tradeoffs that takes into account the strategic, trial-to-trial behavior of the performer. The strategic behavior enables individuals to maximize movement speed while minimizing error and energy expenditure.     

Drivers' compliance with speed limits: an application of the theory of planned behavior

The theory of planned behavior (TPB; I. Ajzen, 1985) was applied to drivers' compliance with speed limits. Questionnaire data were collected for 598 drivers at 2 time points separated by 3 months. TPB variables, demographic information, and self-reported prior behavior were measured at Time 1, and self-reported subsequent behavior was measured at Time 2. In line with the TPB, attitude, subjective norm, and perceived control were positively associated with behavioral intention, and intention and perceived control were positively associated with subsequent behavior. TPB variables mediated the effects of age and gender on behavior. Prior behavior was found to moderate the perceived control-intention and perceived control-subsequent behavior relationships. Practical implications of the findings for road safety and possible avenues for further research are discussed.     

Refinements in the Rorschach Ego Impairment Index incorporating the human representational variable

The Ego Impairment Index (EII; Perry & Viglione, 1991) is a composite measure of psychological impairment and thought disturbance developed from the empirical and theoretical literature on the Rorschach. In this article, we summarize reliability and validity data regarding the EII. Our major goal was to present the rationale and empirical basis for recent refinements in the EII. Among the subcomponents of the original EII was the Human Experience variable (HEV), which has recently been revised and replaced with the Human Representational variable (HRV; Viglione, Perry, Jansak, Meyer, & Exner, 2003). In this study, we replaced the HEV with the HRV to create the EII-2. This was accomplished by recalculating the factor coefficients with a sample of 363 Rorschach protocols. We present additional validity data for the new EII-2. Research recommendations and interpretive guidelines are also presented.     

Children's working-memory processes: a response-timing analysis

Recall response durations were used to clarify processing in working-memory tasks. Experiment 1 examined children's performance in reading span, a task in which sentences were processed and the final word of each sentence was retained for subsequent recall. Experiment 2 examined the development of listening-, counting-, and digit-span task performance. Responses were much longer in the reading-and listening-span tasks than in the other span tasks, suggesting that participants in sentence-based span tasks take time to retrieve the semantic or linguistic structure as cues to recall of the sentence-final words. Response durations in working-memory tasks helped to predict academic skill and achievement, largely separate from the contributions of the memory spans themselves. Response durations thus are important in the interpretation of span task performance.     

PUNISHMENT IN HUMAN CHOICE: DIRECT OR COMPETITIVE SUPPRESSION?

This investigation compared the predictions of two models describing the integration of reinforcement and punishment effects in operant choice. Deluty's (1976) competitive-suppression model (conceptually related to two-factor punishment theories) and de Villiers' (1980) direct-suppression model (conceptually related to one-factor punishment theories) have been tested previously in nonhumans but not at the individual level in humans. Mouse clicking by college students was maintained in a two-alternative concurrent schedule of variable-interval money reinforcement. Punishment consisted of variable-interval money losses. Experiment 1 verified that money loss was an effective punisher in this context. Experiment 2 consisted of qualitative model comparisons similar to those used in previous studies involving nonhumans. Following a no-punishment baseline, punishment was superimposed upon both response alternatives. Under schedule values for which the direct-suppression model, but not the competitive-suppression model, predicted distinct shifts from baseline performance, or vice versa, 12 of 14 individual-subject functions, generated by 7 subjects, supported the direct-suppression model. When the punishment models were converted to the form of the generalized matching law, least-squares linear regression fits for a direct-suppression model were superior to those of a competitive-suppression model for 6 of 7 subjects. In Experiment 3, a more thorough quantitative test of the modified models, fits for a direct-suppression model were superior in 11 of 13 cases. These results correspond well to those of investigations conducted with nonhumans and provide the first individual-subject evidence that a direct-suppression model, evaluated both qualitatively and quantitatively, describes human punishment better than a competitive-suppression model. We discuss implications for developing better punishment models and future investigations of punishment in human choice.     

Effects of alternative reinforcement on human behavior: the source does matter

Competing theories regarding the effects of delivering periodic response-independent reinforcement (more accurately, response-independent points exchanged for money) on a baseline rate of behavior were evaluated in human subjects. Contiguity theory holds that these events decrease target responding because incompatible behavior is adventitiously strengthened when the point deliveries follow target behavior closely in time. Matching theory holds that response-independent points, like any other alternative reinforcer, should reduce target responding. On this view, temporal contiguity between target responding and response-independent point delivery is unimportant. In our experiment, four different responses (moving a joystick in four different directions) were reinforced with points exchangeable for money according to four independent variable-interval schedules. Different schedules of point delivery were then superimposed on these baselines. When all superimposed point deliveries occurred immediately after one of the four responses (the target response), time allocated to target responding increased. When the superimposed point deliveries could be delivered at any time, time allocated to target responding declined and other behavior increased. When superimposed points could never immediately follow target responses, time allocated to target responding decreased further and other behavior or pausing predominated. The findings underscore the contribution of temporal contiguity in the effects of response-independent deliveries of food, money, points, etc.