The effects of iPod and text-messaging use on driver distraction: a bio-behavioral analysis

This study was designed to empirically examine the effects of iPod device and text-messaging activities on driver distraction. Sixty participants were asked to perform a driving simulation task while searching for songs using an iPod device or text messaging. Driving errors as measured by lane deviations were recorded and analyzed as a function of the distracters. Physiological measures (EEG) were also recorded during the driving phases in order to measure participant levels of cortical arousal. It was hypothesized that iPod use and text messaging would result in a profound effect on driving ability. The results showed a significant effect of iPod use and text-messaging on driving performance. Increased numbers of driving errors were recorded during the iPod and text-messaging phases than the pre- and post-allocation phases. Higher levels of Theta activity were also observed during the iPod and Text-messaging phase than the pre- and post-allocation phases. Implications for in-vehicle systems design, training, and safety are also discussed.

Behavioral influences of proximal alarms

Confidence in and responses to an unreliable test alarm were studied in the presence of nearby unspecified alarms. The test alarm's reliability rate was represented as averaging "true" only 50% or 60% of the time. Confidence or response rates ranged proportionately from 23% to 97% with the number of active alarms within 5, 6, 7, or 9 annunciator arrays. Adjacent alarms resulted in confidence estimates that were higher (by about 10%) than those with the same number of active alarms spaced up to 3 positions away. Simultaneously activated alarms resulted in a more than 20% increase in "true" responses compared with the same number of alarms offset in time by up to 32 s, regardless of which came first. Active alarms "known" to be functionally related to, or independent of, the test alarm substantially raised or lowered responding but did not completely overcome prior effects. These findings indicate that presumptions that operators' responses are not influenced by nearby alarms, regardless of their function, may be unwarranted. Applications of this research include suggestions to improve responding and training recommendations.

Effects of adaptive task allocation on monitoring of automated systems

The effects of adaptive task allocation on monitoring for automation failure during multitask flight simulation were examined. Participants monitored an automated engine status task while simultaneously performing tracking and fuel management tasks over three 30-min sessions. Two methods of adaptive task allocation, both involving temporary return of the automated engine status task to the human operator ("human control"), were examined as a possible countermeasure to monitoring inefficiency. For the model-based adaptive group, the engine status task was allocated to all participants in the middle of the second session for 10 min, following which it was again returned to automation control. The same occurred for the performance-based adaptive group, but only if an individual participant's monitoring performance up to that point did not meet a specified criterion. For the nonadaptive control groups, the engine status task remained automated throughout the experiment. All groups had low probabilities of detection of automation failures for the first 40 min spent with automation. However, following the 10-min intervening period of human control, both adaptive groups detected significantly more automation failures during the subsequent blocks under automation control. The results show that adaptive task allocation can enhance monitoring of automated systems. Both model-based and performance-based allocation improved monitoring of automation. Implications for the design of automated systems are discussed.

Mechanisms of visual-spatial attention: resource allocation or uncertainty reduction?

Many studies have found that stimuli can be discriminated more accurately at attended locations than at unattended locations, and such results have typically been taken as evidence for the hypothesis that attention operates by allocating limited perceptual processing resources to attended locations. An alternative proposal, however, is that attention acts to reduce uncertainty about target location, thereby increasing accuracy by decreasing the number of noise sources. To distinguish between these alternatives, we conducted 6 spatial cuing experiments in which target location uncertainty was eliminated. Despite the absence of uncertainty, target discriminations were more accurate at the attended location, consistent with resource allocation models. These cue validity effects were observed under a broad range of conditions, including central and peripheral cuing, but were absent at very short cue-target delay intervals.

Aging and cognitive vigilance: effects of spatial uncertainty and event rate

Age-related differences in cognitive vigilance were examined in a task requiring identification of a target (a lowercase letter) presented at three levels of spatial uncertainty (low, moderate, and high) and in the context of a low or high event rate. Thirty-six young (18-24 years) and 36 older (60-74 years) adults participated in 30-min vigilance sessions. Increased spatial uncertainty decreased target detection rate and d' to a greater extent in older adults than in young adults. No age differences were obtained for the low-spatial-uncertainty condition. The vigilance decrement--the decline in detection rate over time--was magnified when event rate was high and when spatial uncertainty was high. The results suggest that cognitive vigilance is age sensitive when demands on visual attention capacity are increased by high event rate or spatial uncertainty.

Effects of spatial cuing on luminance detectability: psychophysical and electrophysiological evidence for early selection

Three experiments were conducted to determine whether attention-related changes in luminance detectability reflect a modulation of early sensory processing. Experiments 1 and 2 used peripheral cues to direct attention and found substantial effects of cue validity on target detectability; these effects were consistent with a sensory-level locus of selection but not with certain memory- or decision-level mechanisms. In Experiment 3, event-related brain potentials were recorded in a similar paradigm using central cues, and attention was found to produce changes in sensory-evoked brain activity beginning within the 1st 100 ms of stimulus processing. These changes included both an enhancement of sensory responses to attended stimuli and a suppression of sensory responses to unattended stimuli; the enhancement and suppression effects were isolated to different neural responses, indicating that they may arise from independent attentional mechanisms.

Effects of spatial cuing on luminance detectability: psychophysical and electrophysiological evidence for early selection

Three experiments were conducted to determine whether attention-related changes in luminance detectability reflect a modulation of early sensory processing. Experiments 1 and 2 used peripheral cues to direct attention and found substantial effects of cue validity on target detectability; these effects were consistent with a sensory-level locus of selection but not with certain memory- or decision-level mechanisms. In Experiment 3, event-related brain potentials were recorded in a similar paradigm using central cues, and attention was found to produce changes in sensory-evoked brain activity beginning within the 1st 100 ms of stimulus processing. These changes included both an enhancement of sensory responses to attended stimuli and a suppression of sensory responses to unattended stimuli; the enhancement and suppression effects were isolated to different neural responses, indicating that they may arise from independent attentional mechanisms.

Visual attention modulates signal detectability

The mechanism by which visual-spatial attention affects the detection of faint signals has been the subject of considerable debate. It is well known that spatial cuing speeds signal detection. This may imply that attentional cuing modulates the processing of sensory information during detection or, alternatively, that cuing acts to create decision bias favoring input at the cued location. These possibilities were evaluated in 3 spatial cuing experiments. Peripheral cues were used in Experiment 1 and central cues were used in Experiments 2 and 3. Cuing similarly enhanced measured sensitivity, P(A) and d', for simple luminance detection in all 3 experiments. Under some conditions it also induced shifts in decision criteria (beta). These findings indicate that visual-spatial attention facilitates the processing of sensory input during detection either by increasing sensory gain for inputs at cued locations or by prioritizing the processing of cued inputs.

Visual attention modulates signal detectability

The mechanism by which visual-spatial attention affects the detection of faint signals has been the subject of considerable debate. It is well known that spatial cuing speeds signal detection. This may imply that attentional cuing modulates the processing of sensory information during detection or, alternatively, that cuing acts to create decision bias favoring input at the cued location. These possibilities were evaluated in 3 spatial cuing experiments. Peripheral cues were used in Experiment 1 and central cues were used in Experiments 2 and 3. Cuing similarly enhanced measured sensitivity, P(A) and d', for simple luminance detection in all 3 experiments. Under some conditions it also induced shifts in decision criteria (beta). These findings indicate that visual-spatial attention facilitates the processing of sensory input during detection either by increasing sensory gain for inputs at cued locations or by prioritizing the processing of cued inputs.