Perceptual assumptions and projective distortions in a three-dimensional shape illusion

We examine a shape illusion, in which the balconies of a building appear to tilt up or down, depending on the viewpoint. The balconies are actually level parallelogram shapes, but appear as tilted rectangles. We measured the illusory tilts observed when parallelogram shapes are viewed above the line of sight, using three-dimensional stimuli consisting of parallelograms of various tilts viewed at different orientations. Under perspective projection, parallelism and orthogonality are not preserved. However, perspective distortions alone cannot account for the perceived tilts measured in these experiments, since observers perceived illusory tilts even for stimuli in the frontoparallel plane. We introduce a model, based on the theory that observers assume ambiguously projected three-dimensional angles to be equal to 90 degrees, but revise their predictions on the basis of observation. In the model, perceived tilt is predicted as a weighted sum of the tilts predicted by the assumptions that the shape is rectangular, and that the shape is level (i.e. that the angle between the shape and the vertical backboard is equal to 90 degrees). We prove that it is mathematically impossible for a planar rectangle to share a projection with a nonrectangular parallelogram. A less restrictive assumption that just the two leading internal angles are equal to 90 degrees is suggested as an alternative, and it is further proven that this new configuration of angles leads to a unique perceived tilt. The relative weights in the model reflect the amount that each prediction is revised, and are shown to vary systematically with stimulus orientation. For some observers a better fit was found by replacing the level-tilt assumptions with an assumption that physical tilt was equal to the projected tilt.     

Competing strategies in categorization: expediency and resistance to knowledge restructuring

The authors investigated people's ability to restructure their knowledge when additional information about a categorization task is revealed. In 2 experiments, people first learned to rely on a fairly accurate (but imperfect) predictor. At various points in training, a complex relationship between 2 other predictors was revealed in a schematic diagram that could support perfect performance. In Experiment 1, people adopted the complex strategy when it was revealed at the outset but were unable to restructure their knowledge after the expedient predictor had been learned. In Experiment 2, expedient knowledge persisted even with an adaptive display. The persistence of expedient knowledge is explained by associative blocking of potential alternative cues. A 3rd experiment analyzed the strategies people use with and without the diagram. The study confirmed that the diagram, when presented at the outset, significantly alters people's approach to the task.     

Problem solving deteriorates following mood challenge in formerly depressed patients with a history of suicidal ideation

The authors divided 34 participants who had a history of depression into 2 groups, those having previous suicidal ideation or behavior (n=19) and those having no such symptoms (n=15), then compared the 2 groups with a group of participants who had no history of depression (n=22). Assessment of interpersonal problem-solving performance using the Means-Ends Problem-Solving (MEPS) task before and after a mood-induction procedure showed that only those formerly depressed people with a history of suicidal ideation shifted in MEPS performance, producing significantly less effective problem solutions following mood challenge, consistent with a differential activation account of vulnerability for recurrence of suicidal ideation and behavior. The deterioration in effectiveness following mood challenge was moderated by lack of specificity in autobiographical memory.     

Online attentional-focus manipulations in a soccer-dribbling task: implications for the proceduralization of motor skills

A focus of attention on the step-by-step control of a skill has been shown to be detrimental to experts' performance but to have no significant effect on novices' performance (e.g., S. L. Beilock, T. H. Carr, C. MacMahon, & J. L. Starkes, 2002), contrary to the results of manipulations of the direction of attentional focus (e.g., G. Wulf, M. H?ss, & W. Prinz, 1998). In previous studies, researchers have not separated the focus of attention from the nature of the instruction provided or the skill level of the participants. In the present experiment, 10 skilled and 10 less skilled soccer players dribbled a ball after receiving instructions directing attention to an internal, skill-relevant feature (foot); an internal, skill-irrelevant feature (arm); or a skill-irrelevant task (word-monitoring). Performance was evaluated in relation to a no-attentional-focus control condition. For skilled performers, an internal focus on the arms and feet interfered with performance. For less skilled performers, an internal, yet skill-relevant, focus of attention (foot) did not degrade performance, whereas attention to the arms and word monitoring had a detrimental effect. No significant differences were observed across the three attentional manipulations when the skilled performers used the nondominant foot. The results generally supported the deautomization of skills hypothesis.     

A Lesson from My Father

Simple acts can heal. And God is present in those simple and humble acts. The following is a true story that illustrates these truths, told from the perspective of eyewitness, son, and physician.     

Concordant Spiritual Orientations as a Factor in Physician--Patient Spiritual Discussions: A Qualitative Study

Objectives: To understand the impact of physicians and patients religious/spiritual orientation on discussions of spiritual issues. Methods: We performed semi-structured interviews of 10 Missouri family physicians and 10 patients of these physicians, selecting subjects nonrandomly to represent a range of demographic factors, practice types, and chronic or terminal illness. We coded and evaluated transcribed interviews for themes. Results: Respondents expressed that similar belief systems facilitate patient–physician spiritual interactions and bring confidence to their relationships. Those holding dissimilar faiths noted limited ability to address spiritual questions directly. They cited significant barriers to spiritual interaction but considered that ecumenism, use of patient-centered care, and negotiation skills lessen these barriers. Conclusions: Our respondents view spirituality similarly to other aspects of the physician–patient relationship involving differing viewpoints. Where discordance exists, cross-cultural, patient-centered, diplomatic approaches facilitate spiritual discussions.     

Exploring the hand test with medically ill children and adolescents

Pediatric psychologists use the tools of assessment to evaluate the psychological functioning of youth with chronic and acute medical illnesses. This study is an exploration of the use of a performance-based measure, the Hand Test (HT; Wagner, 1983), with pediatric medical patients. A sample of medical inpatients (n = 27) and psychiatric outpatients (n = 24) were administered the HT, a self-report measure, and a parent-report behavior rating scale. Results indicate that the psychiatric group scored higher than the medical group on HT Aggression, Withdrawal, and Pathological scores. The Aggression (d = 0.90) and Pathological (d = 0.80) variables were particularly robust in differentiating between groups, but the Crippled variable did not differ between groups. Hierarchical logistic regression demonstrated the incremental validity of the HT over behavior ratings alone in the classification of clinical groups. Analyses indicated that the HT can add important information in the differentiation of medically ill children from those with psychological disturbance.     

A conceptual and psychometric framework for distinguishing categories and dimensions

An important, sometimes controversial feature of all psychological phenomena is whether they are categorical or dimensional. A conceptual and psychometric framework is described for distinguishing whether the latent structure behind manifest categories (e.g., psychiatric diagnoses, attitude groups, or stages of development) is category-like or dimension-like. Being dimension-like requires (a) within-category heterogeneity and (b) between-category quantitative differences. Being category-like requires (a) within-category homogeneity and (b) between-category qualitative differences. The relation between this classification and abrupt versus smooth differences is discussed. Hybrid structures are possible. Being category-like is itself a matter of degree; the authors offer a formalized framework to determine this degree. Empirical applications to personality disorders, attitudes toward capital punishment, and stages of cognitive development illustrate the approach.     

Validity and reliability of the audit and CAGE-AID in Northern Plains American Indians

According to the Indian Health Service, substance abuse and Type 2 diabetes are serious problems among Native Americans. To assess substance use in a medical setting, valid screening tests are needed so the Alcohol Use Disorders Identification Test (AUDIT), a simple brief screen for excessive drinking, and the CAGE-adapted to Include Drugs (CAGE-AID) for identifying primary care patients with alcohol and drug disorders were given 50 Northern Plains American Indians with diabetes. Both are short, easy to administer, have good sensitivity and specificity, and can be easily incorporated into a medical history protocol or intake procedure. Reliability coefficients were above .90 and appeared to have sufficient concurrent and divergent validity indicated by moderate correlations with the General Well-being Schedule (rs=-.39 and -.36), the Family-Adaptation, Partnership, Growth, Affection, & Resolve (r =-.47 and -.36), and the Beck Depression Inventory-IT (r = .36 and .29).