Vasopressin, glucose homeostasis, and sucrose taste preferences

Previous research indicates that vasopressin-containing (LE) rats are capable of adapting to the stress of food restriction, whereas vasopressin-deficient (DI) rats cannot adapt to this stressor. It has been postulated that abnormalities in glucose metabolism may be one of the factors leading to the demise of food-restricted DI rats. The present study was conducted to determine if taste preferences are altered in DI animals and if the presentation of exogenous glucose, in the form of sucrose solutions, can ameliorate the effects of the stress of food restriction. Four different concentrations of sucrose solutions were presented to LE and DI rats under the food-restricted condition. In both strains, an 8% sucrose solution was preferred over 0%, 16%, and 32% concentrations, with DI rats consuming more of this concentration than LE rats. Thus, when DI rats had the opportunity of maintaining glucose homeostasis by exogenous supplements, they maintained body weight, displayed no stomach pathology, and survived.     

Memory trace development along a coarse-to-fine dimension; a study supporting a progressively finer attributes theory

This study presents two experiments that demonstrate that the memory trace of a tobe-remembered item develops along a dimension (continuum) from coarse/general to fine/specific. Similarly, forgetting is shown to be a reverse movement along this dimension from fine to coarse, as increasingly less fine attributes are lost. The attribute acquisition pattern of this Progressively Finer Attributes Theory is robust and predictable, valid for experimentally unstructured (Experiment 2) as well as experimentally structured (Experiment 1) material.     

Perceived motion in structure from motion: Pointing responses to the axis of rotation

We investigated the ability to match finger orientation to the direction of the axis of rotation in structure-from-motion displays. Preliminary experiments verified that subjects could accurately use the index finger to report direction. The remainder of the experiments studied the perception of the axis of rotation from full rotations of a group of discrete points, the profiles of a rotating ellipsoid, and two views of a group of discrete points. Subjects’ responses were analyzed by decomposing the pointing responses into their slant and tilt components. Overall, the results indicated that subjects were sensitive to both slant and tilt. However, when the axis of rotation was near the viewing direction, subjects had difficulty reporting tilt with profiles and two views and showed a large bias in their slant judgments with two views and full rotations. These results are not entirely consistent with theoretical predictions. The results, particularly for two views, suggest that additional constraints are used by humans in the recovery of structure from motion.     

Syntactic determinants of stuttering in the spontaneous speech of normally fluent and stuttering children

Conflicting findings have been reported concerning whether fluent children use more complex syntactic structures than stutterers and whether or not stutterers experience specific difficulty with complex syntactic structures. On critical examination, the first of these apparent discrepancies appears to be due to (a) differences in the methods employed for syntactic analysis in different studies, and (b) misleading impressions gained by looking at speakers within a single age range. Data were reanalyzed where one method of analysis had shown that fluent speakers and stutterers did not differ with regard to syntactic structures used but where they did show a propensity for stuttering to occur on complex syntactic structures. These data cover a range of age groups. When the second method of syntactic analysis was applied, a difference was found between fluent speakers and stutterers, with the stutterers initially using more simple structures and fewer complex ones. This difference decreased over age groups. However, a difference still remained with respect to which syntactic structures stutterers experience difficulty. An additional analysis, not formerly conducted on these data, showed that, as reported elsewhere, there was a higher probability of stuttering on clause-initial and. It was also shown that this tendency decreased with age group of the stutterers.     

The temporal selectivity of additive factor effects on the reaction process revealed in ERP component latencies

An experiment was conducted to relate individual components of the event-related brain potential to specific stages of information processing in a two-choice reaction time (RT) task in a group of undergraduate students. Specifically, the latency of the P300 component and the lateralized readiness potential (LRP) were studied as a function of variations in stimulus degradation and response complexity. It was hypothesized that degrading the stimulus would delay the P300 and LRP to the same extent as RT, and that increasing response complexity would affect RT but not P300 latency. The extant literature did not permit any hypothesis regarding the effect of response complexity on LRP latency. The two task variables were found to have additive effects on RT. As predicted, variations in stimulus degradation influenced the latencies of both components, whereas alterations in response complexity had no effect on P300 latency. A significant new finding was that the onset latency of the LRP remained unchanged across levels of response complexity. The overall pattern of results supports the notion of temporal selectivity of stage manipulations that is derived from discrete stage models of human information processing. Furthermore, these results refine the functional interpretation of the LRP by indicating that within the conceptual framework of a stage model the processes this component indexes succeed the start of response choice but precede the start of motor programming.     

Obsessive intrusive thoughts in nonclinical subjects. Part I. Content and relation with depressive, anxious and obsessional symptoms

The present study reports on the development and preliminary validation of a 52 item self-report instrument designed to assess intrusive thoughts, images and impulses that are similar to the aggressive, sexual and disease-related thinking characteristic of clinical obsessions. Two hundred and ninety-three students completed the Obsessive Intrusions Inventory (OII) as well as standard self-report measures of negative cognitions and obsessive, anxious and depressive symptoms. Regression analysis revealed that intrusive thinking was a significant and unique predictor of obsessional but not anxious or depressive symptoms. Furthermore, intrusive thinking showed a moderate correlation with anxious but not depressive cognitions. The results indicate that the intrusive thoughts assessed by the OII are distinct from other forms of negative thinking and may, in fact, constitute an analogue form of clinical obsessions in nonclinical populations.     

The WISC-III: A reality check

Although the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) is arguably the best instrument currently available for assessing students' intelligence, its use will present practitioners, especially school psychologists, with some unique challenges. Recent research suggests that significant reductions in special education students' WISC-III Verbal, Performance, and Full Scale IQ scores will be found, compared with their previous WISC-R results. This finding will have a profound impact on special education placement decisions. Specifically, students who were previously found eligible for learning disability programs may now no longer evidence the significant discrepancies necessary in order to receive continued services. Conversely, students earlier identified as “slow learners” may now be eligible to receive services for those classified under the category of educably mentally handicapped. In addition, the notion that the WISC-III may underestimate the ability of certain populations of students requires further exploration. This article will address these issues as well as implications for practitioners presently administering the WISC-III.