Time-pressure effects on performance in a base-rate task

Researchers assume that time pressure impairs performance in decision tasks by invoking heuristic processes. In the present study, the authors inquired (a) whether it was possible in some cases for time pressure to improve performance or to alter it without impairing it, and (b) whether the heuristic invoked by base-rate neglect under direct experience can be identified. They used a probability-learning design in 2 experiments, and they measured the choice proportions after each of 2 possible cues in each experiment. In 1 comparison, time pressure increased predictions of the more likely outcome, which improved performance. In 2 comparisons, time pressure changed the choice proportions without affecting performance. In a 4th comparison, time pressure hindered performance. The choice proportions were consistent with heuristic processing that is based on cue matching rather than on cue accuracy, base rates, or posterior probabilities.     

Menstrual cycle effects on task performance examined in the context of stress research

The study examined the effects of degree of paramenstrual distress, signal frequency, task load and time on task on psychomotor performance across the menstrual cycle. Simple reaction time, choice reaction time and pursuit tracking were the tasks employed, and performance was assessed using the metrics of mean level, variability, and errors of omission and commission. The results showed performance as a function of menstrual cycle phase and paramenstrual distress to be highly task and metric specific, a finding typical of stressor variables: pursuit tracking was affected by phase, with mean performance at its worst premenstrually; choice reaction time was dependent on a complex interaction of experimental variables and measurement metrics; simple reaction time showed no significant effects. Patterns of attention allocation in a time-sharing situation combining both pursuit tracking and choice reaction time components were also investigated. Trends here indicated relatively better performance both menstrually and intermenstrually as components increased in signal/response frequency, with a corresponding deterioration premenstrually. Overall performance capacity appeared to be greatest at menstruation, and the degree of attentional selectivity was least. High distress women performed better on low frequency components, whereas asymptomatic women did better at higher signal rates.     

The effects of music and task difficulty on performance at a visual vigilance task

Forty subjects performed a visual vigilance task in music or noise and when the task was difficult or easy. Response measures taken were: correct detections, commission errors, detection latencies and d' values. For the difficult version of the task a significant increase in detection latencies was found which music prevented. Broadly similar findings were obtained for correct detections. The results are compared with other studies of detection latency and task difficulty and are discussed in terms of arousal.     

The effects of age and task context on Stroop task performance

In this study, we investigated the impact of age and task context on Stroop task performance, using error scores, response latencies, and process dissociation estimates (e.g., Lindsay & Jacoby, 1994). Across three experiments, the findings showed that although older adults were able to evaluate Stroop task demands and modify their representations of task context in response to this knowledge, they were less able to maintain and update these representations on a trial-by-trial basis in tasks with high stimulus uncertainty or ambiguity. Moreover, although there was no age-related decline in the ability to modulate print color information, older adults were consistently less able to control the activation of conflicting word information. Together, these findings suggest that whereas age differences in the Stroop task may be magnified under conditions that promote transient failures to maintain task context, the primary source of these differences seems to be a more enduring decline in the efficiency of processes that are responsible for suppressing the activation of irrelevant lexical information.     

The effects of mental representation on performance in a navigation task

In three experiments, we investigated the mental representations employed when instructions were followed that involved navigation in a space displayed as a grid on a computer screen. Performance was affected much more by the number of instructional units than by the number of words per unit. Performance in a three-dimensional space was independent of the number of dimensions along which participants navigated. However, memory for and accuracy in following the instructions were reduced when the task required mentally representing a three-dimensional space, as compared with representing a two-dimensional space, although the words used in the instructions were identical in the two cases. These results demonstrate the interdependence of verbal and spatial memory representations, because individuals' immediate memory for verbal navigation instructions is affected by their mental representation of the space referred to by the instructions.     

The effects of dialogue-based task allocation on system performance in a computer-aided air traffic control task

The present study investigated dialogue-based human-computer task allocation. Five levels of allocation mode, four command strategies and a control condition, were examined in a high-task-load situation using a Latin square design. Five male participants acted as controllers in a simplified representation of an air traffic control system, sharing their task with a computer controller. Performance measures were metered on-line, and subjective ratings were recorded between trials. There were significant differences among the groups in the percentage of planes landed by the human-computer system, the total number of commands executed, and the number of allocation commands used. Other variables suggested for further study include comparisons of input mode, dialogue-initiation style, and degraded performance levels of the computer controller.     

Level of aspiration and performance of chronic psychiatric patients on a simple motor task

The level of aspiration and performance was examined for 25 male psychiatric inpatients whose mean age was 57.4 yr. and mean length of hospitalization was 23.6 yr. For a simple motor task involving flipping a plastic chip over a goal line, each patient expressed the ward and his personal pretask levels of aspiration, performed the task, and expressed his personal posttask aspiration. The expressions of both the ward and pretask levels of aspiration were less than the mean score of a nonhospitalized referent group. Both performance and posttask levels of aspiration were greater than the pretask level. More patients predicted they would perform worse than the other patients on the ward than predicted they would perform better. The patients appropriately shifted their levels of aspiration either up after success or down after failure. The results were discussed according to expectations from classical theory as well as findings with schizophrenics. Implications for further research were discussed.     

The effects of age and task domain on dual task performance: A meta-analysis

Recent research has provided mixed findings as to whether older adults find dual tasking problematic. Here, we examined whether methodological variations across studies can account for the discrepancies in the literature. Meta-analyses conducted on the results of 34 studies conducted between 1981 and 2003 found a strong overall effect size (d = .68), which indicated a clear age-related dual tasking impairment. However, this effect size was not representative of all the individual studies reported. Subsequent analyses, using an analysis of variance analogue (Hedges & Olkin, 1985), investigated potential moderators responsible for the variability in the effect sizes across studies. These secondary analyses included a comparison of dependent measure used, whether baseline differences in performance had been controlled for, and task domain. Task domain was found to be the critical moderator variable. Notably, tasks with a substantial controlled processing, or motor component showed greater dual task impairment than tasks that were relatively simple or relied on automatic processing.     

The effects of workload history on dual task performance

The purpose of this study was to examine the effects of workload history (specifically sudden workload shifts) on performance. A sample of 204 undergraduates was randomly assigned to either a sudden decrease or increase in workload condition. Participants simultaneously performed a memory search task (i.e., primary task) and an auditory vigilance task (i.e., distracter task), while percent correct was recorded. Separate Repeated Measures ANOVA’s revealed a significant treatment effect for the Medium to Low (F(l, 110) = 274.6, p < .01) and Low to Medium (F(l,92) = 148.3, p < .01) conditions. Results supported previous research suggesting that either a sudden decrease (Medium to Low) or increase (Low to Medium) in workload could be detrimental to performance (Cox-Fuenzalida, 2000). More importantly, this study extends the detrimental effects of workload history to a dual task environment. The authors express their gratitude to the research team from the Personality and Human Performance Lab at the University of Oklahoma for their invaluable assistance in data planning and collection.     

The effects of workload history on dual task performance

The purpose of this study was to examine the effects of workload history (specifically sudden workload shifts) on performance. A sample of 204 undergraduates was randomly assigned to either a sudden decrease or increase in workload condition. Participants simultaneously performed a memory search task (i.e., primary task) and an auditory vigilance task (i.e., distracter task), while percent correct was recorded. Separate Repeated Measures ANOVA’s revealed a significant treatment effect for the Medium to Low (F(l, 110) = 274.6, p < .01) and Low to Medium (F(l,92) = 148.3, p < .01) conditions. Results supported previous research suggesting that either a sudden decrease (Medium to Low) or increase (Low to Medium) in workload could be detrimental to performance (Cox-Fuenzalida, 2000). More importantly, this study extends the detrimental effects of workload history to a dual task environment. The authors express their gratitude to the research team from the Personality and Human Performance Lab at the University of Oklahoma for their invaluable assistance in data planning and collection.     

The effects of phenytoin on the performance of rats in a delayed match-to-place task

We have shown previously that phenytoin impairs learning in rats in several different behavioral paradigms (Churchill et al., 1998, 2003; Banks et al., 1999). The present study has examined this drug’s effects on performance in a delayed match-to-place water maze paradigm developed by Steele and Morris (1999). We find that phenytoin retards performance, but only when the inter-trial interval (ITI) is short (i.e., 15-sec). With longer ITIs (i.e., 20-min, 2-hr), the performance of the phenytoin-treated rats was quite comparable to the controls. We suggest that this pattern of results stems from a disruption of spatial working memory, perhaps due to the effects of the drug on hippocampal function (cf., Churchill et al., 1998, 2003). This disruption is, however, not so profound that consolidation is prevented.     

Wais-III matrix reasoning: instruction effects on task perception and performance

Instructions for the Matrix Reasoning subtest of the WAIS-III do not communicate to examinees that the subtest is untimed. The present study examined what percentage of participants (34 women, 26 men, M age = 20.1; 55 Caucasian, 3 African American, 2 Hispanic) made the assumption that Matrix Reasoning was timed, and its effect on examinees' scores. 55% of participants receiving standard instructions retrospectively reported assuming the subtest was timed, and those who did not assume Matrix Reasoning was timed scored significantly higher than participants who did. Participants receiving additional instructions that clarified the untimed nature of Matrix Reasoning scored significantly higher than those receiving standard instructions who believed the subtest was timed.     

Acute versus chronic post-traumatic stress disorder

A photographic lens and filter model is presented which outlines six steps between a person’s perception of stressful life events and their possible eventual development of an illness. Persons developing acute post-traumatic stress disorder differ markedly in their processing of early steps in the model compared to those who go on to suffer from chronic post-traumatic stress disorder. Persons with the acute disorder, with high likelihood of recovery, generally have had enriching early life experiences, use psychological defenses to a moderate degree, and demonstrate ample coping capabilities. Those going on to the chronic disorder, who frequently don’t recover, often report impoverished early life experiences, employ psychological defenses to an extreme degree, and show a paucity of coping skills. These differences are illustrated by histories from survivors of a terrorist bombing and by observations made by the author of returned prisoners of war and civilian hostages.     

The effects of sex differences and evaluation on task performance and aspiration

An investigation was conducted of how evaluation differentially affects the performance and aspiration for future performance of 118 high school boys and girls. Subjects were selected to fit into either a superior or average intelligence group. In the high evaluation condition, subjects were instructed that their intelligence was being evaluated in anagram and visual-motor tasks they performed, while those in the low evaluation condition were instructed that the two tasks were being correlated. It was hypothesized that on a highly evaluated task, girls, when compared to boys, would show greater performance debilitation and would have lower aspirations for future performance. Although sex differences were found in performance debilitation and aspiration for future performance, they were not all in the predicted directions. Girls were equally debilitated in anagram performance under both evaluation conditions, while boys were debilitated in anagram performance only under high evaluation. When both boys and girls demonstrated a performance debilitation on the anagram task, their performance declined approximately 10%. No sex differences in performance were found on the visual-motor task. On both tasks, girls' aspirations were significantly affected by evaluation condition. The girls averaged 89% choosing the more difficult task in the low evaluation condition. Evaluation condition had no significant effect on aspiration for boys on either task. Intelligence showed no significant relationships.     

The effects of task instructor status on prospective memory performance in preschoolers

The present study applied a 2 × 2 experimental design to assess prospective memory (PM) development across preschool age and to examine the effect of task instructor status (researcher vs. significant other) on PM performance in 80 preschool children. Participants were required to name pictures (ongoing task [OT]), and to remember to refrain from naming but instead give a different response to certain target cues (PM task). Although the OT was of comparable difficulty for both age groups (as indicated by no performance differences), results still indicated significantly higher PM performance in 5-year-olds than in 3-year-olds, confirming the age-related increase of PM capacities between 3 and 5 years. Furthermore, results showed a performance-enhancing effect of significant others as task instructors on both age-groups. Post-hoc analysis revealed that 3-year-olds instructed by a significant other still performed marginally worse than 5-year-olds instructed by a researcher, underlining the finding that substantial changes of PM capacities take place during early childhood.