Biomedical subjects

William N Dember

Publications and source records attributed to William N Dember.

5 recordsLinked to original sources

PubMed2006

Training for vigilance: the effect of knowledge of results format and dispositional optimism and pessimism on performance and stress.

This study investigated the impact of knowledge of results (KR) format on the performance and stress associated with a vigilance task. Also examined was the effect of the interaction of KR-format (Hit-KR, False Alarm-KR, Miss-KR, and a composite of all three formats) with dispositional optimism and pessimism on performance outcome and reported stress state. Hypotheses based upon a theory of feedback intervention were tested. KR regarding correct detections and the composite-KR (KR regarding correct detections, false alarms, and missed signals) enhanced perceptual sensitivity. However, False Alarm-KR and Miss-KR did not. Contrary to expectations based on the theory, performance was unrelated to the traits across all KR conditions. However, the effects of KR-format on self-reports of stress depended on the individual's level of pessimism and optimism. In addition, KR format and personality affected the multiple dimensions of stress state in different ways.

Adolescent↗

PubMed2005

Signal regularity and the mindlessness model of vigilance.

Robertson, Manly, Andrade, Baddeley, and Yiend (1997) have proposed that detection failures in vigilance tasks result from a 'mindless' withdrawal of attentional effort from the monitoring assignment. To explore that view, they modified the traditional vigilance task, in which observers make button-press responses to signify the detection of rarely occurring critical signals, to one in which button-press responses acknowledge frequently occurring non-signal events and response withholding signifies signal detection. This modification is designed to promote a mindless withdrawal of attentional effort from the task through routinization. The present study challenges the validity of the mindlessness model by showing that with both types of task, observers utilize subtle patterns in the temporal structure of critical signal appearances to develop expectations about the time course of those appearances that affect performance efficiency. Such expectations enhance performance on the traditional vigilance task, but degrade performance on the modified task.

Adolescent↗

PubMed2004

Effects of sensory modality and task duration on performance, workload, and stress in sustained attention.

The workload and stress associated with a 40-min vigilance task were examined under conditions wherein observers monitored an auditory or a visual display for changes in signal duration. Global workload scores fell in the midrange of the NASA Task Load Index, with scores on the Frustration subscale increasing linearly over time. These effects were unrelated to the sensory modality of signals. However, sensory modality was a significant moderator variable for stress. Observers became more stressed over time as indexed by responses to the Dundee Stress State Questionnaire, with evidence of recovery in the auditory but not the visual condition toward the end of the watch. This result and the finding that signal detection accuracy - although equated for difficulty under alerted conditions - favored the auditory mode, indicate that display modality and time on task should be considered carefully in the design of operations requiring sustained attention in order to enhance performance and reduce stress. Actual or potential applications of this research include domains in which monitoring is a crucial part, such as baggage screening, security operations, medical monitoring, and power plant operations.

Adolescent↗

PubMed2003

Loudness adaptation: fact or artifact?

In the present study, the authors tested the hypothesis that contrast effects confound the Ipsilateral Comparison Paradigm (ICP). Bidirectional referents were used in which base tones of 50 or 70 dB alternated with referents of greater or lesser intensity in a 3.5-min listening period. The contrast hypothesis leads to the expectation that the bidirectional referents would produce opposing effects that should nullify time-based loudness changes in the common base tone. Contrary to that expectation, base-tone loudness declined significantly over time in the context of the bidirectional referents, and the loudness of the referents also declined significantly over time. Thus, the results of the study testified to the validity of the ICP as a contrast-free measure of broad-based loudness adaptation.

Adolescent↗

PubMed2003

The vigilance decrement reflects limitations in effortful attention, not mindlessness.

Robertson, Manly, Andrade, Baddeley, and Yiend (1997) proposed that the decline in performance efficiency over time in vigilance tasks (the vigilance decrement) is characterized by "mindlessness" or a withdrawal of attentional effort from the monitoring assignment. We assessed that proposal using measures of perceived mental workload (NASA-TLX) and stress (Dundee Stress State Questionnaire). Two types of vigilance task were employed: a traditional version, wherein observers made button-press responses to signify detection of rarely occurring critical signals, and a modified version, developed by Robertson et al. to promote mindlessness via routinization, wherein button-press responses acknowledged frequently occurring neutral stimulus events and response withholding signified critical signal detection. The vigilance decrement was observed in both tasks, and both tasks generated equally elevated levels of workload and stress, the latter including cognitions relating to performance adequacy. Vigilance performance seems better characterized by effortful attention (mindfulness) than by mindlessness. Actual or potential applications of this research include procedures to reduce the information-processing demand imposed by vigilance tasks and the stress associated with such tasks.

Adult↗