Fixation-point offsets reduce the latency of saccades to acoustic targets

If an observer’s fixation point is extinguished just prior to the onset of a peripheral target, the latency to saccade to that target is reduced. We show that this "gap effect" is not specific to visual targets. Observers made saccades to a light flash or to a white-noise burst. A warning tone was presented on every trial to control for the possible warning effect of the fixation-point offset. For both target modalities, saccade latencies were significantly reduced when the fixation point was extinguished 200 msec prior to the target onset. Implications of this outcome for interpretations of the gap effect are considered. It is argued that the presence of a gap effect for tones, in conjunction with previous findings, is consistent with the hypothesis that the gap effect is produced by a facilitation of premotor processes in the superior colliculus.     

Size-arrival effects: The potential roles of conflicts between monocular and binocular time-to-contact information, and of computer aliasing

With computer simulations of self-motion, participants approached a floating object and tried to “jump” over it without collision. Participants “jumped” significantly later over small objects than they did over larger objects. This occurred when the displays were viewed monocularly or binocularly, a finding that suggests that such size-arrival effects (DeLucia & Warren, 1994) were not due to a conflict between monocular and binocular cues to time-to-contact (TTC) information (Tresilian, 1994,1995). Moreover, the results further suggest that size-arrival effects are not due to irregularities in TTC information that can occur from computer abasing and that the latter does not always affect TTC estimation; visual information used in such judgments does not seem to be extracted on a frame-by-frame basis.     

Negatively biased recall in children with self-reported symptoms of depression

This study investigated differences in depressed and nondepressed children's recall of positively and negatively reinforced behavior. Twenty-six children with self-reported symptoms of depression in the fourth through sixth grades were compared with a matched sample of 26 nondepressed children to determine if there was a negative bias in depressed children's recall. Subjects first generated guesses of the most common associations to each of a series of 40 words. Later, when compared with their nondepressed peers, the children with depressive symptomology were less accurate in recalling which words they had answered correctly and remembered fewer of their own correct responses. They also did more poorly when asked to recall the correct answers that had been provided by the investigator. The two groups did not differ, however, in their recall of which items had been answered incorrectly or in their recall of their previous wrong responses. These results suggest that children with self-reported depressive symptomology do not remember negative experiences more than do nondepressed children; rather, they recall positive experiences less well. Selective forgetting of positively reinforced behavior could be a serious handicap for depressed children in school. It could also play an important role in the maintenance and perhaps even the etiology of depressive symptomatology in children.We wish to thank Bruce Compas for his helpful comments on an earlier draft of this paper.     

AIDS prevention for intravenous drug users in the community: Street-based education and risk behavior

Conducted a study of behavior change associated with a street-based AIDS education project targeted to intravenous (IV) drug users in San Francisco. Two cross-sections were sampled from drug detoxification clinics and street locations in 1986 (n = 438) and 1987 (n = 623). Significant increases were reported in the percentage of IV drug users who used bleach to decontaminate syringes, who did not share needles in past year, and in condom use. A significant reduction in an index of the number of needle-sharing partners was reported. Respondents ranked treatment program as most important source of AIDS information prior to implementation of the program, and ranked outreach workers as most important after implementation. Findings suggest that this community-based outreach program had at least some impact on knowledge about AIDS and may have led to reductions in behaviors known to transmit HIV.     

Marital Stress, Psychological Distress, and Healthful Dietary Behavior: A Longitudinal Analysis

This longitudinal study examined the role of marital and psychological distress on healthful dietary change. A theoretical model is proposed that specified barriers to healthful dietary behavior as mediating the effect of depressive symptoms, role disagreement, inequity, and education on dietary change over time. Subjects were 97 married couples interviewed in their homes at 2 separate times. Selection in the first wave was by random area sampling based on population concentration. The findings provide evidence of the negative influence of interpersonal and intrapsychic distress on positive dietary change. For wives, marital and psychological distress and the barriers to dietary change were important factors in actual changes in dietary behavior. For both husbands and wives, higher barriers were associated with lesser positive dietary change.