Aerospace Medicine and Biology: A continuing bibliography, supplement 191

A bibliographical list of 182 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1979 is presented

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)

This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Nicotinic Receptor Gene CHRNA4 Interacts with Processing Load in Attention

Background: Pharmacological studies suggest that cholinergic neurotransmission mediates increases in attentional effort in response to high processing load during attention demanding tasks [1]. Methodology/Principal Findings: In the present study we tested whether individual variation in CHRNA4, a gene coding for a subcomponent in a4b2 nicotinic receptors in the human brain, interacted with processing load in multiple-object tracking (MOT) and visual search (VS). We hypothesized that the impact of genotype would increase with greater processing load in the MOT task. Similarly, we predicted that genotype would influence performance under high but not low load in the VS task. Two hundred and two healthy persons (age range = 39–77, Mean = 57.5, SD = 9.4) performed the MOT task in which twelve identical circular objects moved about the display in an independent and unpredictable manner. Two to six objects were designated as targets and the remaining objects were distracters. The same observers also performed a visual search for a target letter (i.e. X or Z) presented together with five non-targets while ignoring centrally presented distracters (i.e. X, Z, or L). Targets differed from non-targets by a unique feature in the low load condition, whereas they shared features in the high load condition. CHRNA4 genotype interacted with processing load in both tasks. Homozygotes for the T allele (N = 62) had better tracking capacity in the MOT task and identified targets faster in the high load trials of the VS task. Conclusion: The results support the hypothesis that the cholinergic system modulates attentional effort, and that commo

Establishing gaze markers of perceptual load during multi-target visual search

Highly-automated technologies are increasingly incorporated into existing systems, for instance in advanced car models. Although highly automated modes permit non-driving activities (e.g. internet browsing), drivers are expected to reassume control upon a 'take over' signal from the automation. To assess a person's readiness for takeover, non-invasive eye tracking can indicate their attentive state based on properties of their gaze. Perceptual load is a well-established determinant of attention and perception, however, the effects of perceptual load on a person's ability to respond to a takeover signal and the related gaze indicators are not yet known. Here we examined how load-induced attentional state affects detection of a takeover-signal proxy, as well as the gaze properties that change with attentional state, in an ongoing task with no overt behaviour beyond eye movements (responding by lingering the gaze). Participants performed a multi-target visual search of either low perceptual load (shape targets) or high perceptual load (targets were two separate conjunctions of colour and shape), while also detecting occasional auditory tones (the proxy takeover signal). Across two experiments, we found that high perceptual load was associated with poorer search performance, slower detection of cross-modal stimuli, and longer fixation durations, while saccade amplitude did not consistently change with load. Using machine learning, we were able to predict the load condition from fixation duration alone. These results suggest monitoring fixation duration may be useful in the design of systems to track users' attentional states and predict impaired user responses to stimuli outside of the focus of attention

Face-specific capacity limits under perceptual load do not depend on holistic processing

Previous observations that face recognition may proceed automatically, without drawing on attentional resources, have been challenged by recent demonstrations that only a few faces can be processed at one time. However, a question remains about the nature of the stimulus properties that underlie face-specific capacity limits. Two experiments showed that speeded categorization of a famous face (such as a politician or pop star) is facilitated when it is congruent with a peripheral distractor face. This congruency effect is eliminated if the visual search is loaded with more than one face, unlike previous demonstrations of speeded classification using semantic information. Importantly, congruency effects are also eliminated when the search task is loaded with nontarget faces that are shown in an inverted orientation. These results indicate that face-specific capacity limits are not determined by the configural (“holistic”) properties of face recognition

Response Selection in Visual Search: The Influence of Response Compatibility of Nontargets.

this article should be addressed to Peter A. Starreveld, Department of Cognitive Psychology, Vrije Universiteit, Van der Boechorststraat 1, 1081 BT Amsterdam, the Netherlands. E-mail: [email protected] Journal of Experimental Psychology: Copyright 2004 by the American Psychological Association, Inc. Human Perception and Performance 2004, Vol. 30, No. 1, 56 --78 0096-1523/04/$12.00 DOI: 10.1037/0096-1523.30.1.56 56 As discussed previously, flat slopes of search functions are interpreted as evidence showing that distractor elements in the corresponding experiments were only preattentively processed. Because identification of a display element involves attentive processing, two-stage theories of visual search predict that the identities of distractors should not affect the search time for a target in any search task in which flat search slopes are obtained. In the present study, this prediction was put to the tes

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 144

This bibliography lists 257 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1975

Theories of anterior cingulate cortex function : opportunity cost

The target article highlights the role of the anterior cingulate cortex (ACC) in conflict monitoring, but ACC function may be better understood in terms of the hierarchical organization of behavior. This proposal suggests that the ACC selects extended goal-directed actions according to their learned costs and benefits and executes those behaviors subject to depleting resources

The Effect Of Perceptual Load On Attention Switching

Automation in the car is becoming progressively more sophisticated and we are now approaching a critical junction, where vehicles will be capable of taking care of all aspects of driving but with the expectation that the driver will promptly respond to a request to take-over. With drivers already engaging in a variety of non-driving tasks, it becomes crucial to evaluate the assumption of their readiness to intervene. While simulator studies have partly addressed this expectation by comparing different non- driving tasks, no research has tried to systematically vary the attentional demands of the non-driving tasks and measure their impact on the take-over process. Here, aided by the conceptual framework provided by Perceptual Load Theory, I explore two different scenarios showing how manipulation of attentional load in the non-driving task might hamper drivers’ ability to execute different aspects of the take-over process. While testing was performed entirely in the laboratory, each experiment employs tasks designed to be relevant proxies for both the non-driving tasks and the take-over request. In Chapter 2, I present two experiments in which participants are asked to watch a sequence of natural scenes of varied perceptual load – the non-driving task – while monitoring for the occurrence of an auditory stimulus – the take-over request. High perceptual load was associated with reduced detection of the auditory stimulus. The three experiments reported in Chapter 3 instead aim at understanding the extent to which high attentional demands right before a task switch might hamper the ability to correctly process and respond to the motion of other vehicles, assessed with the use of random dot kinematograms. A high level of perceptual load was reliably accompanied by slower responses to the motion stimuli. Finally, in Chapter 4 I describe an fMRI experiment looking at possible neural contributions to the reaction- time delay observed in Chapter 3

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 165, March 1977

This bibliography lists 198 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1977