POSITIVE PRACTICE OVERCORRECTION: THE EFFECTS OF DURATION OF POSITIVE PRACTICE ON ACQUISITION AND RESPONSE REDUCTION

The effects of long and short durations of positive practice overcorrection were studied, for reduction of off-task behavior after an instruction to perform an object-placement task. Off-task behavior, correct responses, and approximate responses were all observed. Off-task behavior received positive practice. The short and long practice durations (30 seconds and 3 minutes) produced equally rapid reduction of off-task behavior and acquisition of correct object-placement performance. Over sessions, much less time was required for positive practice when the short practice duration was used. Approximate responses, which also avoided positive practice, occurred at low rates relative to correct responding. Negative side effects were observed to occur primarily during sessions with long positive practice. These results indicate that use of short durations of positive practice can reduce the practice time required and negative side effects, with no loss of training effectiveness either for reducing inappropriate behavior or increasing a desired alternative behavior.     

Effects of d- versus l-amphetamine, food deprivation, and current intensity on self-stimulation of the lateral hypothalamus, substantia nigra, and medial frontal cortex of the rat.

Intracranial sefl-stimulation (ICSS) was studied in rats with chronically implanted lateral hypothalamic, substantia nigra, or medial frontal cortex bipolar electrodes. A comparison of the effects of d- and l-amphetamine on ICSS response rate indicated that the d isomer had a greater facilitatory effect than the l isomer at lateral hypothalamic and substantia nigra electrode sites but that neither isomer significantly affected medial frontal cortex ICSS. d-Amphetamine resulted in a dose-related increase in motor activity, but the same doses of the l isomer resulted in decreased motor activity. Only lateral hypothalamic ICSS response rates increased significantly in response to food deprivation. Increases in current intensity above the level used for amphetamine and food-deprivation testing facilitated lateral hypothalamic and substantia nigra ICSS response rates but did not significantly affect medial frontal cortex response rates. The responsiveness of ICSS at each electrode site appeared to be correlated with the fiber- and cell-body densities of catecholaminergic systems in the brain.     

Anatomy of a stimulus domain: The relation between multidimensional and unidimensional scaling of noise bands

Theoretically, there are many possible relationships between multidimensional scaling and unidimensional scalings of the same stimulus domain. In particular, it is uncertain what will happen if the number of psychological “dimensions” exceeds the number of physical variables. The multidimensional scaling of noise bands, unidimensionally a relatively well-understood domain, was done to explore these problems. In correspondence with the number of physical variables, a two-dimensional configuration was found to give a satisfactory account of the judgments of magnitude of stimulus difference. Axes of loudness, volume, and density were found to fit the configuration with a high degree of precision, lending support to the metric value of numbers produced in magnitude estimation. Pitch, or frequency, also had a simple relationship to the configuration, but was not an axis or dimension. Therefore, the usual conceptualization of judgments of overall similarity as the result of combining difference on separate dimensions is questioned. It is suggested that multidimensional configurations may sometimes correspond to internal representations of general importance.     

Association between dyads and correct responses on the Paced Auditory Serial Addition Task (PASAT)

The sensitivity of the Paced Auditory Serial Addition Task (PASAT) to working memory deficits may be enhanced by examining "dyads" (i.e., correct responses immediately preceded by a correct response) as a complement to the traditional total correct summary score. In a sample of 397 mostly African American (79%) healthy adults, total dyad and total correct scores were highly correlated (r = .96, p < .001); however, the magnitude of this association diminished in faster stimulus presentation trials, particularly among participants with impaired working memory abilities.     

Beauty and the beast: Psychobiologic and evolutionary perspectives on body dysmorphic disorder

Body dysmorphic disorder (BDD) is characterized by preoccupation with a defect in appearance. Concepts of beauty play a particularly crucial role in humans' mental and social life, and may have specific psychobiologic and evolutionary underpinnings. In particular, there is a growing literature on the neurocircuitry underpinning the body schema, body image and facial expression processing, and aesthetic and symmetry judgments. Speculatively, disruptions in cognitive-affective processes relevant to judgements about physical beauty lead to BDD.     

Re-visiting the competence/performance debate in the acquisition of the counting principles

Advocates of the "continuity hypothesis" have argued that innate non-verbal counting principles guide the acquisition of the verbal count list (Gelman & Galistel, 1978). Some studies have supported this hypothesis, but others have suggested that the counting principles must be constructed anew by each child. Defenders of the continuity hypothesis have argued that the studies that failed to support it obscured children's understanding of counting by making excessive demands on their fragile counting skills. We evaluated this claim by testing two-, three-, and four-year-olds both on "easy" tasks that have supported continuity and "hard" tasks that have argued against it. A few noteworthy exceptions notwithstanding, children who failed to show that they understood counting on the hard tasks also failed on the easy tasks. Therefore, our results are consistent with a growing body of evidence that shows that the count list as a representation of the positive integers transcends pre-verbal representations of number.     

The least likely of times: how remembering the past biases forecasts of the future

Atypical events are both memorable and unrepresentative of their class. We tested the hypotheses that (a) people tend to recall atypical instances of events, and (b) when they are unaware of this, they rely on these atypical instances in forecasting their affective reactions to future events. In three studies, participants who were asked to recall an instance of an event and participants who were asked to recall an atypical instance of an event recalled equally atypical instances. However, only the former participants made extreme forecasts about their reactions to future events. The results suggest that the impact bias (the tendency to overestimate the affective impact of future events) may be due in part to people's reliance on highly available but unrepresentative memories of the past.     

A PRELIMINARY ANALYSIS OF THE EFFECTS OF PRIOR CLASSROOM CONDITIONS ON PERFORMANCE UNDER ANALOGUE ANALYSIS CONDITIONS

We systematically manipulated two prior classroom conditions to explore their effects on performance under analogue assessments for a 7-year-old girl with severe intellectual disabilities who exhibited aggressive behavior. Results demonstrated consistently higher levels of aggression during demand analogue conditions when they were preceded by one of the classroom conditions.