Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic,familiar scenes by older and younger adults

Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object’s instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18–39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio–visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio–visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.     

Medical Ethics Education: A Survey of Opinion of Medical Students in a Nigerian University

In Nigeria, medical education remains focused on the traditional clinical and basic medical science components, leaving students to develop moral attitudes passively through observation and intuition. In order to ascertain the adequacy of this method of moral formations, we studied the opinions of medical students in a Nigerian university towards medical ethics training. Self administered semi-structured questionnaires were completed by final year medical students of the College of Medicine, University of Ibadan, Nigeria. There were 82 (64.1%) male and 44 (34.4%) female respondents. The median age was 26 years. Most students (80.5%) responded that they did not receive enough training in medical ethics. The ethics instructions they received did not sufficiently prepare them for the ethical challenges they came across as medical students. Though inadequate, the few hours of lecture and discussion on human values and professional etiquette which they received positively influenced their moral reasoning. They identified end-of-life issues, dealing with financial issues and handling socio-cultural beliefs of patients and relations as some challenges that medical doctors are ill-prepared for by their current training. Most, 85.9% believed that formal medical ethics education would be worthwhile as it would enhance the making of complete and better doctors. They recommended incorporating bioethics as a course in the medical school curriculum. Nigerian medical students encounter ethical challenges for which they have not been adequately trained to resolve. They recommended formal medical ethics training in their curriculum and a uniform bioethics programme in the country.     

Relationships of race and socioeconomic status to classroom behavior,academic achievement,and referral for special education

A study was conducted to identify the relationships of race and socioeconomic status (SES) to observed classroom behavior, academic achievement, and special education referral. A sample of 109 fourth-grade boys from varying racial (Anglo, black, and Hispanic) and SES backgrounds was selected and observed systematically on four occasions for 12 behaviors. Data also were collected on academic achievement and special education referral. Multivariate analyses indicated no race-related differences in observed behavior and only one SES-related difference. Black and Hispanic children did not differ reliably, but both were lower than Anglo children in achievement. A non-stepwise discriminant function analysis utilizing race, SES, and observational data as predictors of referral for special education failed to make statistically reliable predictions. The relative unimportance of race and SES as predictors challenges the validity of alleged “institutional racism” in referrals for special education.     

A longitudinal study of children of alcoholics: predicting young adult substance use disorders, anxiety, and depression

This study tested the specificity of parent alcoholism effects on young adult alcohol and drug abuse/dependence, anxiety, and depression, and tested whether adolescent symptomatology and substance use mediated parent alcoholism effects. Participants were from a longitudinal study in which a target child was assessed in adolescence and young adulthood with structured interview measures (N = 454 families at Time 1). Results showed unique effects of parent alcoholism on young adult substance abuse/dependence diagnoses over and above the effects of other parental psychopathology. There was some evidence of parent alcoholism effects on young adult depression and of maternal alcoholism effects on young adult anxiety, although these were not found consistently across subsamples. Mediational models suggested that parent alcoholism effects could be partially (but not totally) explained by adolescent externalizing symptoms.     

Pictorial and motion-based information for depth perception.

When computer-generated objects approached the viewpoint in midair, a large far object appeared to be nearer than a small near object and appeared to hit the viewpoint before the small object, which was specified by time-to-contact information to arrive sooner. These judgements were consistent with relative size and occurred even when motion-based information was potentially above threshold. The effects of relative size persisted with higher resolution animated films of approaching objects, were weakened by ground-intercept information, and were not as robust with laterally translating objects. Although it is often asserted that the kinds of information that have traditionally been called static depth cues are superseded by motion-based depth information, this article attempts to show that the reverse also can occur in distance perception, as has been shown in form perception.     

Pattern uncertainty and the discrimination of visual patterns

Sixty Ss individually sorted eight decks of 50 cards each. A deck contained 25 cards each of two stimulus patterns. The patterns were drawn from different sets of five-dot patterns judged to be equivalent. The eight decks represented pairs of patterns drawn (a) from the same equivalence set, (b) from different equivalence sets of the same size, and (c) from different equivalence sets of different sizes. Sorting times were shown to increase with increasing size of equivalence set, and were shown to be greater for patterns drawn from within the same equivalence set than for patterns drawn from different equivalence sets. Ratings of pattern goodness were found to be useful predictors of sorting time only in their capacity to discriminate between equivalence sets of different sizes. The results were interpreted as supporting the importance of equivalence set membership in a discrimination task where the S logically does not have to consider stimuli other than the given criterion stimuli.     

Line correspondence in binocular vision

The mathematical analysis of binocular vision introduced by Helmholtz is applied to the problem of the use of disparity information to position a stimulus in depth. It is shown that matching the images from the left and right eyes along radial directions is an alternative to matching images along the horizontal direction only.