Vigilance decrement during a simulated general aviation flight

This study examined pilots' vigilance during an extended general aviation flight as measured by their capacity to exercise control over the aircraft during a planned flight. Thirty‐one qualified pilots flew a flight simulator from Wagga Wagga to Bankstown, Sydney, a distance of 207 nautical miles. The flight comprised five separate legs, although three legs were subjected to analysis. On the basis of attentional resource theory, it was hypothesised that task performance would differ based on the requirement for memory retrieval. Consistent with the hypothesis, the results revealed a deterioration in those tasks for which there was a substantial requirement for memory retrieval. Further analysis revealed that the deterioration in performance was best predicted by pilots' perception of the workload associated with the flight and their perception of their ability to exercise control over aircraft during normal conditions. The implications are discussed in terms of system design and training. Copyright © 2010 John Wiley & Sons, Ltd.     

The role of attention in the maintenance of feature bindings in visual short-term memory

This study examined the role of attention in maintaining feature bindings in visual short-term memory. In a change-detection paradigm, participants attempted to detect changes in the colors and orientations of multiple objects; the changes consisted of new feature values in a feature-memory condition and changes in how existing feature values were combined in a binding-memory condition. In the critical experiment, a demanding visual search task requiring sequential shifts of spatial attention was interposed during the delay interval of the change-detection task. If attention is more important for the maintenance of feature bindings than for the maintenance of unbound feature values, the attention-requiring search task should specifically disrupt performance in the binding-memory task. Contrary to this proposal, it was found that memory for bindings and memory for features were equally impaired by the search task.     

Sex differences during visual scanning of occlusion events in infants

A growing number of sex differences in infancy have been reported. One task on which they have been observed reliably is the event-mapping task. In event mapping, infants view an occlusion event involving 1 or 2 objects, the occluder is removed, and then infants see 1 object. Typically, boys are more likely than girls to detect an inconsistency between a 2-object occlusion event and a 1-object display. The current research investigated underlying reasons for this sex difference. Three eye-tracking experiments were conducted with infants at 9 and 4 months (mean age). Infants saw a ball-box or ball-ball occlusion event followed by a 1-ball display; visual scanning of the occlusion event and the 1-ball display was recorded. Older boys were more likely than older girls to visually track the objects through occlusion and more likely to detect an inconsistency between the ball-box event and the 1-ball display. In addition, tracking objects through occlusion was related to infants' scanning of the 1-ball display. Both younger boys and girls failed to track the objects through occlusion and to detect an inconsistency between the ball-box event and the 1-ball display. These results suggest that infants' capacity to track objects through occlusion facilitates extraction of the structure of the initial event (i.e., the number of distinct objects involved) that infants can map onto the final display and that sex differences in the capacity emerge between 4 and 9 months. Possible explanations for how the structure of an occlusion event is extracted and mapped are considered.     

Effects of workload preview on task scheduling during simulated instrument flight

Our study examined pilot scheduling behavior in the context of simulated instrument flight. Over the course of the flight, pilots flew along specified routes while scheduling and performing several flight-related secondary tasks. The first phase of flight was flown under low-workload conditions, whereas the second phase of flight was flown under high-workload conditions in the form of increased turbulence and a disorganized instrument layout. Six pilots were randomly assigned to each of three workload preview groups. Subjects in the no-preview group were not given preview of the increased-workload conditions. Subjects in the declarative preview group were verbally informed of the nature of the flight workload manipulation but did not receive any practice under the high-workload conditions. Subjects in the procedural preview group received the same instructions as the declarative preview group but also flew half of the practice flight under the high-workload conditions. The results show that workload preview fostered efficient scheduling strategies. Specifically, those pilots with either declarative or procedural preview of future workload demands adopted an efficient strategy of scheduling more of the difficult secondary tasks during the low-workload phase of flight. However, those pilots given a procedural preview showed the greatest benefits in overall flight performance.     

Cell phone-induced failures of visual attention during simulated driving

This research examined the effects of hands-free cell phone conversations on simulated driving. The authors found that these conversations impaired driver's reactions to vehicles braking in front of them. The authors assessed whether this impairment could be attributed to a withdrawal of attention from the visual scene, yielding a form of inattention blindness. Cell phone conversations impaired explicit recognition memory for roadside billboards. Eye-tracking data indicated that this was due to reduced attention to foveal information. This interpretation was bolstered by data showing that cell phone conversations impaired implicit perceptual memory for items presented at fixation. The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.     

Perceived object trajectories during occlusion constrain visual statistical learning

Visual statistical learning of shape sequences was examined in the context of occluded object trajectories. In a learning phase, participants viewed a sequence of moving shapes whose trajectories and speed profiles elicited either a bouncing or a streaming percept: the sequences consisted of a shape moving toward and then passing behind an occluder, after which two different shapes emerged from behind the occluder. At issue was whether statistical learning linked both object transitions equally, or whether the percept of either bouncing or streaming constrained the association between pre- and postocclusion objects. In familiarity judgments following the learning, participants reliably selected the shape pair that conformed to the bouncing or streaming bias that was present during the learning phase. A follow-up experiment demonstrated that differential eye movements could not account for this finding. These results suggest that sequential statistical learning is constrained by the spatiotemporal perceptual biases that bind two shapes moving through occlusion, and that this constraint thus reduces the computational complexity of visual statistical learning.     

The accuracy of aimed movements to visual targets during development: the role of visual information

Children aged 1.5 to 8 years were required to touch accurately an illuminated target lamp located on a vertical board. Movements were made when visual information was complete (target lit for 3 s, room illuminated; partial (target lit for 3 s, room dark, and reduced (target lit for 0.7 s, room dark). Dependent variables were response accuracy, reaction time, and movement time. Accuracy decreased with decreasing availability of visual information and improved with age under all conditions. Reaction times were shorter in the dark (Conditions 2 and 3) than in the light; they decreased with age up to age 5 and did not continue to decrease thereafter. Movement time did not change with age under Conditions 1 and 3 but tended to increase with age under Condition 2. Slower movements were more accurate at all ages, provided visual feedback could be utilized. Increased reliance on the strategy "slower movements yield higher accuracy" was held to account for developmental changes under Condition 2, whereas in Conditions 1 and 3 improvement in the efficiency of motor preprogramming was implicated.     

Brain dynamics of visual anticipation during spatial occlusion tasks in expert tennis players

Stimulus identification and action outcome understanding for a rapid and accurate response selection, play a fundamental role in racquet sports. Here, we investigated the neurodynamics of visual anticipation in tennis manipulating the postural and kinematic information associated with the body of opponents by means of a spatial occlusion protocol. Event Related Potentials (ERPs) were evaluated in two groups of professional tennis players (N = 37) with different levels of expertise, while they observed pictures of opponents and predicted the landing position as fast and accurately as possible. The observed action was manipulated by deleting different body districts of the opponent (legs, ball, racket and arm, trunk). Full body image (no occlusion) was used as control condition. The worst accuracy and the slowest response time were observed in the occlusion of trunk and ball. The former was associated with a reduced amplitude of the ERP components likely linked to body processing (the N1 in the right hemisphere) and visual-motor integration awareness (the pP1), as well as with an increase of the late frontal negativity (the pN2), possibly reflecting an effort by the insula to recover and/or complete the most correct sensory-motor representation. In both occlusions, a decrease in the pP2 may reflect an impairment of decisional processes upon action execution following sensory evidence accumulation. Enhanced amplitude of the P3 and the pN2 components were found in more experienced players, suggesting a greater allocation of resources in the process connecting sensory encoding and response execution, and sensory-motor representation.     

The role of occlusion cues in apparent motion

Classical apparent motion stimuli exhibit an inherent ambiguity with respect to the onsets and offsets of the stimulus elements. Sigman and Rock (1974, Perception 3 9-28) presented evidence suggesting that occlusion cues are used to resolve this ambiguity. We present results from experiments designed to further test predictions of this hypothesis. As expected, we found that the apparent motion of a target stimulus is suppressed when a 'moving' occluder is positioned such that it rationalises the onsets and offsets of the stimulus elements constituting the target. Somewhat unexpectedly, though, we also observed a slight tendency for motion suppression under conditions where the target was only partially occluded. The expected motion suppression occurred both with solid occluders and purely virtual Kanizsa-like occluders, although it was not always observed in the latter case. Motion suppression was found to occur over a wide range of stimulus onset asynchronies. Finally, we used binocular disparity cues to test the occlusion account of the motion suppression phenomenon against an alternative explanation in terms of attentional factors. The results are in clear favour of the occlusion account.     

The effects of periodic visual occlusion on ball catching

Four experiments were conducted to examine the effects of periodic visual occlusion on one-handed ball catching. Tennis balls were projected one at a time over distances of 8-12 m, and liquid-crystal visual occlusion spectacles provided intermittent vision by opening and closing the lens shutters at different frequencies. As well as frequency, we manipulated duty cycle, or the proportion of time that the lenses were open. Generally, catching performance deteriorated as frequency was reduced. Although longer visual samples (i.e., increased duty cycle) mediated this effect to some extent, the most potent variable was the time between visual samples; performance deteriorated rapidly when this interval was greater than 80 ms (i.e., 10 Hz with 20-ms lens open times). Presumably this occurred because subjects had difficulty integrating visual information separated by longer temporal intervals.     

The role of vocabulary ability during visual word recognition in younger and older adults

The role that vocabulary ability plays in adult age differences in word recognition was investigated. In Experiment 1, 44 older adults (ages 61-93 years) were compared with 44 younger adults (ages 18-39 years) on a standard lexical-decision task, with ambiguous words, unambiguous words, and pseudowords serving as stimuli. In Experiment 1, the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981) vocabulary performance was uncontrolled across the younger and older adults, and the older adults had higher WAIS-R scores. There was no Group x Stimulus interaction. In Experiment 2, the data from the same 44 older adults were compared with data from a new sample of 44 younger adults (ages 18-44). Both groups were then matched on WAIS-R performance. Results revealed a significant Group x Stimulus interaction. Reaction time differences between the younger and older groups on the ambiguous words and unambiguous words were identical. The differences in reaction times for words and pseudowords were greater in the older adults. The importance of vocabulary ability during word recognition and lexical processing is discussed.     

The role of phonology during visual word learning in adults: An integrative review

Throughout their lifetime, adults learn new words in their native lannguage, and potentially also in a second language. However, they do so with variable levels of success. In the auditory word learning literature, some of this variability has been attributed to phonological skills, including decoding and phonological short-term memory. Here I examine how the relationship between phonological skills and word learning applies to the visual modality. I define the availability of phonology in terms of (1) the extent to which it is biased by the learning environment, (2) the characteristics of the words to be learned, and (3) individual differences in phonological skills. Across these three areas of research, visual word learning improves when phonology is made more available to adult learners, suggesting that phonology can facilitate learning across modalities. However, the facilitation is largely specific to alphabetic languages, which have predictable sublexical correspondences between orthography and phonology. Therefore, I propose that phonology bootstraps visual word learning by providing a secondary code that constrains and refines developing orthographic representations.

     

The role of visual attention in action priming

It has been demonstrated that the task-irrelevant left-right orientation of an object is capable of facilitating left-right-hand responses when the object is orientated towards the responding hand. We investigated the role of attention in this orientation effect. Experiment 1 showed that object orientation facilitates responses of the hand that is compatible with the object's orientation, despite the entire object being irrelevant. However, when a task-relevant fixation point was displayed over the prime object in Experiment 2, the effect was not observed. Together Experiments 1 and 2 suggest that the orientation information of viewed objects primes the action selection processes even when the object is irrelevant, but only when attention is not allocated to a competing stimulus during the prime presentation. Experiment 3 suggested that the elimination of the effect in Experiment 2 could not be attributed to the elimination of an attentional shift to the graspable part of the prime. Finally, Experiment 4 showed that object orientation can evoke an abstract response code, influencing the selection of finger responses.     

The role of visual imagery in autobiographical memory

Visual imagery plays a fundamental role in autobiographical memory, but several aspects of this role remain unclear. We conducted three experiments to explore this relationship. In the first experiment, we examined the relation between the phenomenological properties of autobiographical memory and several measures of visual-imagery ability. We found no significant positive relation between imagery ability and autobiographical memory, except on a measure of cognitive style. In a second experiment, we examined the autobiographical memories of people with different cognitive styles—namely, visualizers and verbalizers. We found that, for both kinds of participant, visual imagery was correlated with the feeling that they were reliving their memories, but auditory imagery played a greater role in verbalizers. In a third experiment, we examined the memories of individuals who had a congenital absence of visual imagery. We found that they had a deficit of auditory imagery, as well; moreover, they were much less likely than controls to feel as though they were reliving their memories. The results support the idea that visual imagery plays a vital and irreplaceable role in autobiographical recall.     

The role of the amygdala in visual awareness

Pessoa and colleagues recently reported the novel finding that objective awareness of a negative stimulus is associated with coactivation of the amygdala and fusiform gyrus. Based on the neuroanatomical connections of the amygdala, we suggest that the amygdala is acting to increase neural activity in the fusiform gyrus, thereby increasing the likelihood that visual representations that have affective value reach awareness. The psychological consequence is that a person's momentary affective state might help to select the contents of conscious experience.     

The role of visual perspective in information processing

Social events can be described from the perspective of either a person in the situation in which the event occurs (e.g., “John came into…”) or that of an outside observer (“John went into…”). We find that when individuals are disposed to form visual images, they have difficulty comprehending both verbal statements and pictures when the perspective from which the event is described differs from the perspective from which they have encountered similar events in daily life. Furthermore, the disposition to form visual images increases the intensity of emotional reactions to an event when the event is described from the perspective of someone in the situation in which it occurs. These effects are not evident, however, among individuals who typically process information semantically without forming visual images.     

The role of priming in conjunctive visual search

To assess the role of priming in conjunctive visual search tasks, we systematically varied the consistency of the target and distractor identity between different conditions. Search was fastest in the standard conjunctive search paradigm where identities remained constant. Search was slowest when potential target identity varied predictably for each successive trial (the 'switch' condition). The role of priming was also demonstrated on a trial-by-trial basis in a 'streak' condition where target and distractor identity was unpredictable yet was consistent within streaks. When the target to be found was the same for a few trials in a row, search performance became similar to that when the potential target was the same on all trials. A similar pattern was found for the target absent trials, suggesting that priming is based on the whole search array rather than just the target in each case. Further analysis indicated that the effects of priming are sufficiently strong to account for the advantage seen for the conjunctive search task. We conclude that the role of priming in visual search is underestimated in current theories of visual search and that differences in search times often attributed to top-down guidance may instead reflect the benefits of priming.