The contributions of static visual cues, nonvisual cues, and optic flow in distance estimation

By systematically varying cue availability in the stimulus and response phases of a series of same-modality and cross-modality distance matching tasks, we examined the contributions of static visual information, idiothetic information, and optic flow information. The experiment was conducted in a large-scale, open, outdoor environment. Subjects were presented with information about a distance and were then required to turn 180 before producing a distance estimate. Distance encoding and responding occurred via: (i) visually perceived target distance, or (ii) traversed distance through either blindfolded locomotion or during sighted locomotion. The results demonstrated that subjects performed with similar accuracy across all conditions. In conditions in which the stimulus and the response were delivered in the same mode, when visual information was absent, constant error was minimal; whereas, when visual information was present, overestimation was observed. In conditions in which the stimulus and response modes differed, a consistent error pattern was observed. By systematically comparing complementary conditions, we found that the availability of visual information during locomotion (particularly optic flow) led to an 'under-perception' of movement relative to conditions in which visual information was absent during locomotion.     

An evaluation of mood states among first-year residents

To examine the need for preventive and treatment interventions, a prevalence study was conducted to ascertain the rate of depressive symptomatology and other negative mood states among 112 first-year residents. The participation rate was 54%. Subjects (N = 61) were administered the Beck Depression Inventory and Profile of Mood States in personal interview sessions. The Profile measures five negative mood states, namely, "tension-anxiety," "depression-dejection," "anger-hostility," "fatigue-inertia," "confusion-bewilderment," and one positive state, "vigor-activity." A 15.5% rate of depression was found, which is lower than a rate of 23.5%, also measured by Beck's inventory, among a sample of university undergraduates and 19.9% among an adult sample from the general population. No differences were observed among residency programs or sex on Beck's scale; however, significantly higher scores were found for women on the "depression-dejection" dimension of the Profile. The mean scores on all negative mood dimensions of the Profile were below the mean for university undergraduate norms. Neither sleep nor hours worked over the past week were associated with increased Beck scores. These results indicate that sleep deprivation and long work hours did not contribute to depression among the subjects who participated in the study. Female interns, however, appear to be at increased risk of depression, and adequate support systems need to be provided.