Detection of collision events on curved trajectories: optical information from invariant rate-of-bearing change

Previous research (Andersen & Kim, 2001) has shown that a linear trajectory collision event (i.e., a collision between a moving object and an observer) is specified by objects that expand and maintain a constant bearing (the object location remains constant in the visual field). In the present study, we examined the optical information for detecting a collision event when the trajectory was of constant curvature. Under these conditions, a collision event is specified by expansion of an object and a constant rate-of-bearing change. Three experiments were conducted in which trajectory curvature and display duration were varied while time to contact, speed, and initial image position of the collision objects were maintained. The results indicated that collision detection performance decreased with an increase in trajectory curvature and decreased with a decrease in display duration, especially for highly curved trajectories. In Experiment 3, we found that the presentation of a constant rate-of-bearing change in noncollision stimuli resulted in an increase in the false alarm rate. These results demonstrate that observers can detect collision events on curved trajectories and that observers utilize bearing change information.     

The relational self: an interpersonal social-cognitive theory

The authors propose an interpersonal social-cognitive theory of the self and personality, the relational self, in which knowledge about the self is linked with knowledge about significant others, and each linkage embodies a self-other relationship. Mental representations of significant others are activated and used in interpersonal encounters in the social-cognitive phenomenon of transference (S. M. Andersen & N. S. Glassman, 1996), and this evokes the relational self. Variability in relational selves depends on interpersonal contextual cues, whereas stability derives from the chronic accessibility of significant-other representations. Relational selves function in if-then terms (W. Mischel & Y. Shoda, 1995), in which ifs are situations triggering transference, and thens are relational selves. An individual's repertoire of relational selves is a source of interpersonal patterns involving affect, motivation, self-evaluation, and self-regulation.     

Perceptual information and attentional constraints in visual search of collision events

This study examined the detection of collision events when multiple moving objects were present in the scene. Observers were presented with displays simulating a 3-D environment with multiple moving objects. The authors examined the ability of observers to detect collisions using a signal-detection paradigm and a visual search paradigm. The results indicated that, overall, observers were quite accurate at detecting collisions. Observers used both expansion information and static position to detect collisions, with expansion information being the more important source. Singleton search conditions were not processed in parallel, and conjunction search conditions had poorer performance than singleton search conditions. In addition, reaction times were greater for target-present trials as compared with target-absent trials. The results are interpreted in terms of 4 visual search hypotheses for collision detection when multiple moving objects are present.     

The relation of illness perceptions to stress,depression, and fatigue in patients with chronic lymphocytic leukaemia

Objective: Chronic lymphocytic leukaemia (CLL) is the most prevalent adult leukaemia and is incurable. The course and treatment of CLL is unique and characterised by repeated cycles of treatment, stable disease and relapse. Utilising a Self-Regulatory Model framework, we examined the relationship between patients’ illness perceptions and cancer-specific stress, depressive symptoms and fatigue. Our aim was to test illness perceptions as predictors of these outcomes when variance due to disease and treatment variables was controlled.

Design: Data were collected on 147 patients with relapsed/refractory CLL as they entered a phase II clinical trial of an investigational medication at a university affiliated, National Cancer Institute designated comprehensive cancer center.

Main outcome measures: Cancer-specific stress, depressive symptoms and fatigue interference.

Result:. Hierarchical multiple regression was used. Consequences and emotional representation were related to all outcomes (ps?p?p?Conclusion: Illness perceptions are related to cancer-specific stress, depressive symptoms and fatigue interference in relapsed/refractory CLL. Interventions targeted at restructuring maladaptive illness perceptions may have clinical benefit in this population.     

Contributions of weight perceptions to weight loss attempts: Differences by body mass index and gender

Previous studies have consistently observed that women are more likely to perceive themselves as overweight compared to men. Similarly, women are more likely than men to report trying to lose weight. Less is known about the impact that self-perceived weight has on weight loss behaviors of adults and whether this association differs by gender. We conducted a cross-sectional analysis among an employee sample (n = 899) to determine the association of self-perceived weight on evidence-based weight loss behaviors across genders, accounting for body mass index (BMI) and demographic characteristics. Women were more likely than men to consider themselves to be overweight across each BMI category, and were more likely to report attempting to lose weight. However, perceiving oneself to be overweight was a strong correlate for weight loss attempts across both genders. The effect of targeting accuracy of self-perceived weight status in weight loss interventions deserves research attention.     

A common mechanism in verb and noun naming deficits in Alzheimer’s patients

We tested the ability of Alzheimer’s patients and elderly controls to name living and non-living nouns, and manner and instrument verbs. Patients’ error patterns and relative performance with different categories showed evidence of graceful degradation for both nouns and verbs, with particular domain-specific impairments for living nouns and instrument verbs. Our results support feature-based, semantic representations for nouns and verbs and support the role of inter-correlated features in noun impairment, and the role of noun knowledge in instrument verb impairment.     

Stabilizing and Changing Phenomenal Worlds: Ludwik Fleck and Thomas Kuhn on Scientific Literature

In the work of both Ludwik Fleck and Thomas Kuhn the scientific literature plays important roles for stability and change of scientific phenomenal worlds. In this article we shall introduce the analyses of scientific literature provided by Fleck and Kuhn, respectively. From this background we shall discuss the problem of how divergent thinking can emerge in a dogmatic atmosphere. We shall argue that in their accounts of the factors inducing changes of scientific phenomenal worlds Fleck and Kuhn offer substantially different approaches, and we shall discuss in which respects their approaches may be compatible. This revised version was published online in August 2006 with corrections to the Cover Date.     

Kuhn's Account Of Family Resemblance: A Solution To The Problem Of Wide-Open Texture

It is a commonly raised argument against thefamily resemblance account of concepts that, on thisaccount, there is no limit to a concept's extension.An account of family resemblance which attempts toprovide a solution to this problem by including bothsimilarity among instances and dissimilarity tonon-instances has been developed by the philosopher ofscience Thomas Kuhn. Similar solutions have beenhinted at in the literature on family resemblanceconcepts, but the solution has never received adetailed investigation. I shall provide areconstruction of Kuhn's theory and argue that hissolution necessitates a developmental perspective withbuilds on both the transmission of taxonomies betweengenerations and a progressive development throughhistory.     

Optimism, perceived risk of breast cancer, and cancer worry among a community-based sample of women.

Optimism is frequently inversely associated with distress; however, less is known about the mechanisms underlying this relationship. Optimism can be defined as having a generalized positive expectancy about the future. The authors hypothesized that a specific expectancy might mediate the relationship between optimism and distress. That model was tested using perceived risk of breast cancer as a specific measure of expectancy and cancer worry as a measure of distress in a community-based sample of 1,366 women. It was hypothesized that optimism would be inversely associated with cancer worry and that perceived risk of breast cancer would mediate the relationship between optimism and cancer worry. Multiple regression analyses revealed that perceived risk partially mediated the relationship between optimism and cancer worry.