Spatial versus tree representations of proximity data

In this paper we investigated two of the most common representations of proximities, two-dimensional euclidean planes and additive trees. Our purpose was to develop guidelines for comparing these representations, and to discover properties that could help diagnose which representation is more appropriate for a given set of data. In a simulation study, artificial data generated either by a plane or by a tree were scaled using procedures for fitting either a plane (KYST) or a tree (ADDTREE). As expected, the appropriate model fit the data better than the inappropriate model for all noise levels. Furthermore, the two models were roughly comparable: for all noise levels, KYST accounted for plane data about as well as ADDTREE accounted for tree data. Two properties of the data proved useful in distinguishing between the models: the skewness of the distribution of distances, and the proportion of elongated triangles, which measures departures from the ultrametric inequality, Applications of KYST and ADDTREE to some twenty sets of real data, collected by other investigators, showed that most of these data could be classified clearly as favoring either a tree or a two-dimensional representation.A portable PASCAL program implementing the Sattath and Tversky [1977] ADDTREE algorithm is available from J. Corter, Department of Psychology, Stanford University, Stanford, California 94305.     

Recall of common and distinctive features of verbal and pictorial stimuli

Subjects first rated similarity of verbal and of pictorial stimuli. The same pairs of stimuli were presented again, without one common component and one distinctive component. Subjects were asked to recall the missing components and identify them as common or distinctive. The results show that components encoded as common are recalled relatively better than components encoded as distinctive, and the difference in recall is significantly greater in verbal than in pictorial stimuli.     

Visual angle and the word superiority effect

Two experiments are reported in which a word superiority effect is obtained under conditions where a fixed set of alternatives are employed with positional certainty as to the critical letter, trial type (word or nonword) is mixed, and the subject is told to fixate the position of the critical letter. A third experiment employed the same methodology except for the fact that the stimuli subtended a larger retinal angle. No word superiority effect was observed in the third experiment. It is suggested that the visual angle of the stimulus display is a crucial factor in experiments on the word superiority effect.     

Does legally mandated consent to psychotherapy ensure ethical appropriateness?: the Colorado experience

We analyzed a sample of 356 forms containing information that Colorado law legally requires both licensed and unlicensed therapists to disclose to clients. The majority of forms contained the legally mandated information; fewer forms contained ethically desirable information. The average readability grade level was 15.74, corresponding to upper-level college, and 63.9% of the forms reached the highest (most difficult) readability grade of 17+. Therapists are obeying the law, but do not appear to be taking advantage of the opportunity to provide their clients useful information in an accessible way.     

Neuropeptide and cardiovascular responses to intravenous catheterization in normotensive and hypertensive blacks and whites

Research suggests that heightened cardiovascular and neuroendocrine (typically catecholamine) responses to stressors may lead to the development of hypertension and that there may be race differences in patterns of reactivity that are potentially pathogenic. Certain neuropeptides exert profound effects on blood pressure (BP) and heart rate (HR), yet no published studies have examined relationships between these peptides, hypertensive status, race, and reactivity. Seventeen Black and 20 White normotensive and borderline-hypertensive male 19- to 50-year-olds underwent intravenous catheterization while cardiovascular and neuropeptide responses to the stress of being catheterized were examined. Results indicate that, in response to the stressor, Black hypertensives, showed significantly lower endorphin levels compared to Black normotensives, and White hypertensives showed significantly higher levels of beta-endorphin compared to White normotensives. Groups were not significantly different in endorphin levels at recovery. Black hypertensives also showed significantly higher stressor-induced HR and systolic and diastolic BP compared to White hypertensives and normotensives. Lower levels of beta-endorphin and lower urine sodium excretion were associated with higher BP and HR.     

God and the evangelical laboratory: Recent conservative Protestant thinking about theology and science

This review essay surveys 14 recent texts on theology and science published by six different evangelical (conservative Protestant) publishing houses since 1999. The spectrum of evangelical-theological approaches to evolution, natural history, and origins-of-life issues are presented in these texts, as are evangelical-theological perspectives on the Intelligent Design phenomenon, on theological and scientific method, and on the philosophy of science. Summary observations about the status quaestiones of the theology-and-science discussion in the evangelical world at the beginning of the twenty-first century are provided, and future developments anticipated among conservative Protestants in their engagements with the sciences.     

Mental and Motor Switching in Parkinson's Disease

Switching difficulties in Parkinson's disease (PD) are expressed in both mental and motor tasks. The authors of the present study investigated whether those deficits coexist in the same patient and are positively correlated. They tested 8 nondemented PD patients and 6 age-matched control participants by using the modified Wisconsin Card Sorting Test and a motor switching paradigm that is based on the task of reaching toward visual targets, the location of which could unexpectedly be altered within the reaction time. In both mental and motor tasks, patients performed significantly worse than controls. There were no significant correlations between the two types of pathology in individual patients. Mental and motor switching deteriorate in PD patients, but the deficits are not necessarily of parallel severity.

basal ganglia