Plasticity of feature-based selection in triple-conjunction search.

Two experiments examined the disruption of feature-based selection in triple-conjunction search at multiple target transfers. In Experiment 1, after 10 training sessions, a new target possessing previous distractor features was introduced. This produced disruption in RT and fixation number, but no disruption in feature-based selection. Specifically, there was a tendency to fixate objects sharing the target's contrast polarity and shape and this did not change even upon transfer to the new target. In Experiment 2, 30 training sessions were provided with three target transfers. At the first transfer, the results replicated Experiment 1. Subsequent transfers did not produce disruption on any measure. These findings are discussed in terms of strength theory, Guided Search, rule-based approaches to perceptual learning, and the area activation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Static and dynamic visual sensitivity in older adults.

Many visual changes accompany the aging process, even in the absence of known visual pathology. One such change which has attracted recent attention is that "normal" older adults, on average, exhibit diminished contrast sensitivity (CS). This loss is not of a general nature, but rather is restricted to intermediate and higher spatial frequencies. Age-related decline in CS has been attributed to both optical (e.g., retinal illuminance, light scatter) and neural factors (e.g., cell loss in higher-order neurons). Three experiments evaluated CS in adults of varying ages. These experiments were intended to 1) establish provisional age norms for the Vistech Contrast Test System, a recently developed method for CS evaluation; 2) assess the convergent and construct validity of the Vistech charts against an optical/neural model of age-related differences in spatial vision; and 3) determine the degree to which these age-deficits in CS were magnified in a dynamic contrast sensitivity (DCS) task where bifoveal fixation requires accurate smooth pursuit. Results demonstrate that the Vistech charts appear to possess good convergent validity with respect to age differences in spatial vision. In addition to declines in spatial vision, older adults are less able to smoothly pursue a moving stimulus. This decline in smooth pursuit accuracy suggested that age differences in CS would be magnified when the elderly were required to discern contrast in a moving stimulus. Two studies have produced results which are consistent with this argument. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term reliability of a brief hazard perception test

Hazard perception tests (HPTs) have been successfully implemented in some countries as a part of the driver licensing process and, while their validity has been evaluated, their short-term stability is unknown. This study examined the short-term reliability of a brief, dynamic version of the HPT. Fifty-five young adults (M_age = 21 yrs) with at least two years of post-licensing driving experience completed parallel, 21-scene HPTs with a one-month interval separating each test. Minimal practice effects (∼0.1 s) were manifested. Internal consistency (Cronbach's alpha) averaged 0.73 for the two forms. The correlation between the two tests was 0.55 (p < 0.001) and correcting for lack of reliability increased the correlation to 0.72. Thus, a brief form of the HPT demonstrates acceptable short-term reliability in drivers whose hazard perception should be stable, an important feature for implementation and consumer acceptance. One implication of these results is that valid HPT scores should predict future crash risk, a desirable property for user acceptance of such tests. However, short-term stability should be assessed over longer periods and in other driver groups, particularly novices and older adults, in whom inter-individual differences in the development of hazard perception skill may render HPT tests unstable, even over short intervals.     

Age differences in saccadic averaging.

Younger and older adults were asked to saccade to an orientation-defined target that was presented alone, with a more central distractor, or with a more peripheral distractor. Both age groups exhibited saccadic averaging that was more pronounced in the central distractor condition, wherein older adults had the larger effect. These results are relevant to questions of oculomotor control and also have implications for the study of age differences in other visually guided behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A hazard perception test for novice drivers

We developed a hazard perception test, modeled on that used currently in several Australian states, that presents short video scenes to observers and requires them to indicate the presence of a traffic conflict that would lead to a collision between the “camera” vehicle and another road user. After eliminating those scenes that were problematic (e.g., many observers did not recognize the hazard), we predicted driver group (novice vs. experienced drivers of similar age) on the basis of individual differences in reaction time, miss rate and false alarm rate. Novices were significantly slower in responding to hazards, even after controlling for age and simple reaction time. After selecting those scenes with the larger group differences, an 18-scene test that would be useful for mass testing exhibited even larger experience effects. There was good reliability in the resulting scale. Results suggest that this brief test of hazard perception can discriminate groups that differ in driving experience. Implications for driver licensing, evaluation and training are discussed.     

Age differences in trust and reliance of a medication management system

The present study examined age differences in trust and reliance of an automated decision aid. In Experiment 1, older and younger participants performed a simple mathematical task concurrent with a simulated medication management task. The decision aid was designed to facilitate medication management, but with varying reliability. Trust, self-confidence and usage of the aid were measured. The results indicated that older adults had greater trust in the aid and were less confident in their performance, but they did not calibrate trust differently than younger adults. In Experiment 2, a variant of the same task was used to investigate whether older adults are subject to over-reliance on the automation. Differences in omission and commission errors were examined. The results indicated that older adults were more reliant on the decision aid and committed more automation-related errors. A signal detection analyses indicated that older adults were less sensitive to automation failures. Results are discussed with respect to the perceptual and cognitive factors that influence age differences in the use of fallible automation.     

A meta-analysis of the effects of cell phones on driver performance

The empirical basis for legislation to limit cell phones while driving is addressed. A comprehensive meta-analysis of the effects of cell phones on driving performance was performed. A total of 33 studies collected through 2007 that met inclusion criteria yielded 94 effect size estimates, with a total sample size of approximately 2000 participants. The dependent variables of reaction time, lateral vehicle control, headway and speed and the moderating variables of research setting (i.e., laboratory, simulator, on-road), conversation target (passenger, cell phone) and conversation type (cognitive task, naturalistic) were coded. Reaction time (RT) to events and stimuli while talking produced the largest performance decrements. Handheld and hands-free phones produced similar RT decrements. Overall, a mean increase in RT of .25s was found to all types of phone-related tasks. Observed performance decrements probably underestimate the true behavior of drivers with mobile phones in their own vehicles. In addition, drivers using either phone type do not appreciably compensate by giving greater headway or reducing speed. Tests for moderator effects on RT and speed found no statistically significant effect size differences across laboratory, driving simulation and on-road research settings. The implications of the results for legislation and future research are considered.     

Age differences in target identification as a function of retinal location and noise level: Examination of the useful field of view.

Foveal and peripheral target detection were compared in young adults (M age?=?22 years) and older adults (M age?=?66 years) who were optically corrected for the viewing distance. In a two-alternative, forced-choice task, target letters were presented at 0° to 10.5° from fixation. Targets were presented alone, flanked on each side by one noise element (i.e., nontarget letter), or embedded in a horizontal row of 19 noise elements. An Age?×?Noise Level?×?Eccentricity interaction was obtained, wherein age differences were largest for peripheral targets presented in noise. Slope analyses of latency data showed that the performance of young adults in the high-noise condition was most similar to that of older adults in the low-noise condition. At the functional level, results indicated that aging is associated with a restricted useful field of view. In addition, the data suggest that age differences in search can be described by a model in which older adults take smaller perceptual samples from the visual scene and scan these samples more slowly than do the young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictors of web navigation performance in a life span sample of adults

The influence of age, subject matter knowledge, working memory, reading abilities, spatial abilities, and processing speed on Web navigation was assessed in a sample of 41 participants between the ages of 19 and 83 years. Each participant navigated a stand-alone tourism Web site to find answers to 12 questions. Performance was measured using time per trial, number of pages per trial, and number of revisited pages per trial. Age did not influence the number of total pages or repeat pages visited, which were predicted by domain knowledge, working memory, and processing speed. Age was associated with slower times per trial, and the effect remained significant after controlling for working memory, processing speed, and spatial abilities. Only with the addition of subject matter knowledge and World Wide Web experience was the age effect eliminated. Actual or potential applications of this research include redesigning Web sites to minimize memory demands and enhance visual segmentation. The data also suggest that age differences in Web navigation can be offset partially by taking advantage of older adults' prior experiences in the domain.