The integration of orientation information in the motion correspondence problem

We examine how differently oriented components contribute to the discrimination of motion direction along a horizontal axis. Stimuli were two-frame random-dot kinematograms that were narrowband filtered in spatial frequency. On each trial, subjects had to state whether motion was to the left or the right. For each stimulus condition, Dmax (the largest displacement supporting 80% correct direction discrimination performance) was measured. In experiment 1, Dmax was measured for orientationally narrowband stimuli as a function of their mean orientation. Dmax was found to increase as the orientation of the stimuli became closer to the axis of motion. Experiment 2 used isotropic stimuli in which some orientation bands contained a coherent motion signal, and some contained only noise. When the noise band started at vertical orientations and increased until only horizontal orientations contained a coherent motion signal, Dmax increased slightly. This suggests that near-vertical orientations interfere with motion perception at large displacements when they contain a coherent motion signal. When the noise band started at horizontal and increased until only vertical orientations contained the motion signal, Dmax decreased steadily. This implies that Dmax depends at least partly on the most horizontal motion signal in the stimulus. These results were contrasted with two models. In the first, the visual system utilises the most informative orientations (nearest horizontal). In the second, all available orientations are used equally. Results supported an intermediate interpretation, in which all orientations are used but more informative ones are weighted more heavily.     

The acquisition of complex predicates in japanese specifically language-impaired and normally developing children

Japanese exhibits two different types of morphological processes. Some morphologically complex predicates are generated within the domain of the lexicon, whereas others are generated outside the domain of the lexicon. An elicited production task involving both types of complex predicates was administered to six Japanese children with specific language impairment (JSLI) and six children with normal language development (JNLD). The JSLI children experienced significant difficulty forming the lexicon-external complex predicates but much less difficulty with the lexicon-internal complex predicates while the performance of the JNLD children exhibited no such asymmetry. These preliminary results suggest that the deficit of SLI affects the ability to construct implicit procedural rules for morphology that are generated outside the lexicon while their lexical operations for morphology that are generated within the domain of the lexicon remain relatively unimpaired.     

Normative perceptions in relation to substance use and HIV-risky sexual behaviors of college students

In this study, 410 college students completed a survey assessing their personal substance use patterns and sexual behavior and their perceptions of other students' substance use and sexual behavior. Two parallel sets of questions were presented to reflect the two contextual conditions of being drunk or high versus being not drunk or high. Results indicated that number of recent sexual partners and normative perceptions of HIV-risky sexual behavior were the strongest predictors of personal HIV-risky behavior when not drunk or high. HIV-risky behavior when drunk or high was predicted by personal substance use as well as by number of recent partners and normative perceptions of peer sexual behavior. These findings suggest that HIV-prevention programs for college students should aim to correct overinflated perceptions of other students' high-risk sexual behavior.     

On fatalism, pessimism, and depressive symptoms among Mexican-American and other adolescents attending an obstetrics-gynecology clinic

There is growing evidence that Mexican-American adolescents may be at increased risk for depressive symptoms. We sought to replicate and explain this result in a study of adolescent girls attending an obstetric-gynecologic clinic. Three hundred and four girls of diverse ethnic backgrounds completed measures of depressive symptoms, negative attributional style, and locus of control. Consistent with predictions, we found that Mexican-American adolescent girls reported more depressive symptoms than adolescent girls from other ethnic backgrounds, and that Mexican-American adolescent girls displayed more negative cognitive styles than girls from other ethnic backgrounds. Depression differences appeared to be partly explained by differences in negative cognitive style. Implications of the results for a theory of increased Mexican-American adolescent depression, and for applied work, were discussed.     

Distinguishing obsessive features and worries: the role of thought-action fusion

Obsessions are a key feature of obsessive-compulsive disorder (OCD), and chronic worry is the cardinal feature of generalized anxiety disorder (GAD). However, these two cognitive processes are conceptually very similar, and there is a need to determine how they differ. Recent studies have attempted to identify cognitive processes that may be differentially related to obsessive features and worry. In the current study we proposed that (1) obsessive features and worry could be differentiated and that (2) a measure of the cognitive process thought-action fusion would distinguish between obsessive features and worry, being strongly related to obsessive features after controlling for the effects of worry. These hypotheses were supported in a sample of 173 undergraduate students. Thought-action fusion may be a valuable construct in differentiating between obsessive features and worry.     

Diagnostic differences in social anhedonia: a longitudinal study of schizophrenia and major depressive disorder

This study examined the hypothesis that, in schizophrenia, elevated trait social anhedonia (SA) is a stable individual difference, whereas in depression, increased SA is a reflection of a current clinical state that will diminish with recovery. Differences in trait Negative Affect (NA) and Positive Affect (PA) were also examined. Individuals with schizophrenia (n = 55) and depression (n = 34) were evaluated at baseline during hospitalization and compared with nonpsychiatric control participants (n = 41). Participants were assessed again at a 1-year follow-up. At baseline, compared with control participants, individuals with schizophrenia and depression were both characterized by elevated SA, greater NA, and lower PA. In schizophrenic individuals, elevated SA remained stable over the follow-up. However, in recovered depressed patients, SA declined over the follow-up period. Group differences remained in NA and PA over the 1-year follow-up. These results support the view that elevated SA is enduring in schizophrenia but that elevated SA is transiently related to clinical status in depression.     

Development of cognitive averaging: when light and light make dark

In two experiments we studied developmental changes in reasoning about intensive quantities. In contrast to previous studies, color--an intensive quantity that is readily perceivable--was chosen as stimulus material. Children between 6 and 12 years of age and adults predicted the mixture intensity of pairs of liquids with different intensities of red color, the liquid volumes in the two source glasses either being the same (Experiment 1) or different (Experiment 2). The data show that cognitive averaging in this domain develops late and slowly. An extensitivity bias, a strong tendency to use rules (adding in particular) that hold for extensive but not for intensive quantities, predominated up to the age of 12 years and was not totally absent in adults. Contrary to common expectation, children's use of the correct averaging rule became more likely when an extensive quantity, volume, was also varied and thus the task increased in complexity.     

Exploring the role of individual differences in the prediction of workplace aggression

This study investigates the relationship between individual differences and the incidence of workplace aggression in a sample of employees from a transportation company and a public school system. Hierarchical multiple regression analysis indicated that measures of trait anger, attribution style, negative affectivity, attitudes toward revenge, self-control, and previous exposure to aggressive cultures accounted for 62% of the variance in the participants' self-reported incidence of workplace aggression. Further research on workplace aggression is advocated, focusing on the role of individual differences and their interactions with organizational and group-level variables.     

Mental rotation of objects retrieved from memory: a functional MRI study of spatial processing

This functional MRI study examined how people mentally rotate a 3-dimensional object (an alarm clock) that is retrieved from memory and rotated according to a sequence of auditory instructions. We manipulated the geometric properties of the rotation, such as having successive rotation steps around a single axis versus alternating between 2 axes. The latter condition produced much more activation in several areas. Also, the activation in several areas increased with the number of rotation steps. During successive rotations around a single axis, the activation was similar for rotations in the picture plane and rotations in depth. The parietal (but not extrastriate) activation was similar to mental rotation of a visually presented object. The findings indicate that a large-scale cortical network computes different types of spatial information by dynamically drawing on each of its components to a differential, situation-specific degree.