Differences In Allocation Of Attention Research Articles

Attention–memory interactions in scene perception

The perception of natural scenes relies on the integration of pre-existing knowledge with the immediate results of attentional processing, and what can be remembered from a scene depends in turn on how that scene is perceived and understood. However, there are conflicting results in the literature as to whether people are more likely to remember those objects that are consistent with the scene or those that are not. Moreover, whether any discrepancy between the likelihood of remembering schema-consistent or schema-inconsistent objects should be attributed to the schematic effects on attention or on memory remains unclear. To address this issue, the current study attempted to directly manipulate attention allocation by requiring participants to look at (i) schema-consistent objects, (ii) schema-inconsistent objects, or (iii) to share attention equally across both. Regardless of the differential allocation of attention or object fixation, schema-consistent objects were better recalled whereas recognition was independent of schema-consistency, but depended on task instruction. These results suggest that attention is important both for remembering low-level object properties, and information whose retrieval is not supported by the currently active schema. Specific knowledge of the scenes being viewed can result in the recall of non-fixated objects, but without such knowledge attention is required to encode sufficient detail for subsequent recognition. Our results demonstrate therefore that attention is not critical for the retrieval of objects that are consistent with a scene's schematic content.

Eccentricity effects on lateral interactions

We attempted to resolve an apparent conflict between the lack of psychophysical evidence of collinear facilitation at the near-periphery and physiological evidence from the monkey showing collinear effects extra-fovealy. We compared collinear and orthogonal configurations to discount facilitation due to reduced positional uncertainty. Detection thresholds were measured for Gabor targets at eccentricities of 0°–4°, flanked by collinear or orthogonal flankers. Like in previous reports in the literature, results varied among subjects when the stimulus position was off-fixation. We found reduced facilitation at eccentricities as small as 1°–2°. Moreover, facilitation did not increase when the stimuli were M-scaled or when observers received more practice. However, a larger proportion of subjects showed collinear facilitation when attention was directed to the tested configurations. The results suggest that differences in allocation of attention along the visual field may affect the underlying lateral interactions, consequently resulting in eccentricity effects as well as inter-observer variability.

Event-Related Potential Evidence for Age-Related Differences in Attentional Allocation During a Source Monitoring Task

Event-related potentials (ERPs) were recorded while older and younger adults were engaged in a source monitoring task. After studying a list of words, participants were presented with a recognition test during which some of the new words were repeated, rendering them as familiar as the study words. Instructions at test indicated whether the goal was to select the previously studied words or the repeated test items. Behaviorally, the younger adults were less likely to make source monitoring errors. ERPs, averaged only for correct trials, indicated that younger adults produced late positivities of greatest amplitude in response to whichever word type was designated as target irrespective of its familiarity. The ERPs of the older adults were generally less differentiated and their late positivities greater for recently repeated words irrespective of target designation. These results suggest that source monitoring in young adults is facilitated by their ability to allocate and withdraw attention from stimuli on the basis of task relevance rather than familiarity alone, and that this attentional flexibility declines with age.

Differential effects of shared attention on perception of heading and 3-D object motion.

When a person moves in a straight line through a stationary environment, the images of object surfaces move in a radial pattern away from a single point. This point, known as the focus of expansion (FOE), corresponds to the person's direction of motion. People judge their heading from image motion quite well in this situation. They perform most accurately when they can see the region around the FOE, which contains the most useful information for this task. Furthermore, a large moving object in the scene has no effect on observer heading judgments unless it obscures the FOE. Therefore, observers may obtain the most accurate heading judgments by focusing their attention on the region around the FOE. However, in many situations (e.g., driving), the observer must pay attention to other moving objects in the scene (e.g., cars and pedestrians) to avoid collisions. These objects may be located far from the FOE in the visual field. We tested whether people can accurately judge their heading and the three-dimensional (3-D) motion of objects while paying attention to one or the other task. The results show that differential allocation of attention affects people's ability to judge 3-D object motion much more than it affects their ability to judge heading. This suggests that heading judgments are computed globally, whereas judgments about object motion may require more focused attention.

Psychophysiological Basis for Errors in Identification of Degraded Geometric Forms under Conditions of High Information Uncertainty

Identification of ambiguous geometric forms by human subjects with brief experience or pre-knowledge of the stimulus may call upon Bayesian specialised mechanisms. Subjects were presented with a 2-alternative forced choice between a pair of incomplete geometric figures in conditions with common and varying components. Stimuli of 1, 3, 5, and 6 pixel acuity grades were displayed in iterative order in randomised blocks at 100, 200, 260, and 360 ms exposure times, rotated or upright, under local or global viewing. Analysis of probability of correct identification against stimulus intensity, acuity demand, and stimulus duration revealed: (i) sigmoid or dipper-shaped nonmonotonic psychometric functions; (ii) Poisson-like skewed binomial distributions of errors; and (iii) category-based dependence on the stimulus and its ambiguity. This is attributable to the high uncertainty constraints imposed on tasks sharing and also varying in their stimulus parameters and dimensions. Nonlinearities shown reflect category-based strategies and attention allocation, interactions as a drive for performance stability manifested in equalisation across sub-categories and invariances of errors, with acuity demand accounted for perhaps by mechanisms of differential attention allocation. Two sources of error are apparent: (i) possibly ‘bottleneck of attention’-related and individually varying ‘blink of attention’, with small falls distributed across stimulus intensities, and (ii) ‘lapse of attention’ with large falls on easier tasks, and rightward-skewed deviations from normal Poisson-like binomial distributions ( p<0.001), the high correlation to performance effort suggesting an active process of pay-off.

Neuropsychological abnormalities in obsessive-compulsive disorder and their assessments

Neuropsychological test performance of children, adolescents and adults with OCD was very variable. As a group, children and adolescents with OCD had persistent difficulties with executive functions, and show attentional and inhibitory deficits on a continuous performance test. As a group, adults with OCD showed consistent differences in allocation of attention, whether measured by evoked potential, eye movement or reaction time paradigms. They also showed inconsistent problems with visual perceptual discrimination, visual memory and working memory, as well as visuomotor tasks. However, these latter studies all failed to assess attentional capacity concurrently. Traditional measures of lateral prefrontal cortex-basal ganglia functioning tended to be depressed only in those subjects with comorbid depression, obsessional slowness, a large number of neurological soft signs, Tourette's syndrome, and/or lower IQ. Only tasks requiring inhibition of an automatic response correlated with severity of OCD symptoms; these are thought to be subserved by orbitofrontal-subcortical circuits.

Picture media and emotion: effects of a sustained affective context.

Pleasant, neutral, or unpleasant pictures were presented in a continuous series, and the effects of repetitive exposure to pictures of the same affective valence were assessed in somatic (corrugator electromyographic [EMG] activity) and visceral (heart rate and skin conductance) systems. Probe stimuli (startle or reaction time probes) were presented to index emotional and attentional concomitants of processing. Affective discrimination was maintained across time in all response systems, and sensitization was found for the corrugator EMG response. Responses to reaction time probes indexed differences in attentional allocation as a function of cognitive and affective variables in this paradigm. Taken together, the data suggest that presentation of a series of affective pictures of similar valence produces emotional reactions that are either maintained or sensitized across the temporal intervals used here but that do not habituate.

Aging and mechanisms of visual selective attention: Effects on word localization and identification

The present study investigated age differences in attentional allocation in a word localization and identification task. Response times for valid and invalid spatial cue conditions were compared for each of two age groups under two SOA conditions: 500 msec and 1000 msec. Very high benefits for valid cues in terms of response time were found for both groups. Results indicated that attention was more important for words when compared with similar earlier studies using a simple shape identification task. A sensitive model-fitting technique was used to compare the cost and benefit of selective attention to words; it revealed that attention can be concentrated away from the fovea to benefit in word identification in much the same way for both age groups. The model-fit analysis also revealed that attention for word identification, and perhaps any more complex visual stimuli, is more diffuse than for simple shape identification. In addition, older adults are more likely to avoid the foveal area in order to distribute attentional resources to the periphery and are able to increase these effects of selection at the longer SOA. This suggests that older adults are using attention to offset visual processing deficits for peripheral information such as letter information in the reading process. The results support a two-process view of attention where attention consists both of selection and inhibition and provide evidence to support a theory of reduced inhibitory processes as a cause for cognitive slowing associated with aging.

Adult age differences in attentional allocation during memory search.

Adult age differences in attentional allocation during memory search.

Socialization and attentional deficits under focusing and divided attention conditions.

We conducted two studies to test and refine the hypothesis that, when undersocialized individuals focus on events of immediate interest, they allocate too large a proportion of their processing resources to those events and have little attention available for processing other important events. College students who completed the Socialization (So) scale (Gough, 1960) performed visual and auditory tasks simultaneously under conditions favoring the visual task, an equal division of processing resources between the tasks, or both. In both studies, low-So Ss performed relatively poorly on the auditory task under focusing conditions but displayed no primary task advantage and no significant performance deficits under divided attention conditions. These data support the utility of theories relating antisocial behavior to individual differences in allocation of attention. Low-So Ss' unresponsiveness to secondary events is not a simple function of the reallocation of resources to the primary task or a speed-accuracy trade-off. Moreover, under certain conditions, this deficit may disappear, given substantial practice.

Processes Involved in Braille Reading

The purpose of this investigation was to consider whether the input modality and orthographic differences in braille reading produce different word recognition strategies for blind as compared with sighted persons. Blind children, blind adults, and sighted children were compared as to the extent to which they showed a pseudohomophone effect, which is held to reflect phonological coding. While in the sighted individuals there was strong evidence for such an effect, this was not so with the blind persons. The results were interpreted to indicate a differential allocation of attention to levels of word processing between the groups of readers.

Use of Cognitive Capacity in Reading Easy and Difficult Text: Two Tests of an Allocation of Attention Hypothesis

Use of cognitive capacity in reading easy and difficult text was observed with a secondary task technique in 2 experiments. Previous experiments had shown that easy text filled cognitive capacity more completely than difficult text. One hypothesis for this effect is that attention was allocated differentially to easy passages at the expense of difficult ones. Contrary to this hypothesis, in both of the present experiments, content tests showed that a large amount of detailed information was learned from both easy and difficult texts. When the memory load was reduced to reduce the motivation for differential allocation of attention, easy texts continued to fill cognitive capacity more completely than difficult texts. These results were not consistent with an allocation of attention hypothesis. Other hypotheses were considered.