Does attention affect visual feature integration?

Two questions are investigated in this work: first, whether the integration of color and shape information is affected by attending to the stimulus location, and second, whether attending to a stimulus location enhances the perceptual representation of the stimulus or merely affects decision processes. In three experiments, subjects were briefly presented with colored letters. On most trials, subjects were precued to the stimulus location (valid cue); on some trials, a nonstimulus location was cued (invalid cue). Subjects were less likely to incorrectly combine colors and letter shapes following a valid cue. The attentional facilitation afforded by the cue was not limited to feature integration but also affected the registration of features. However, when the amount of feature information was strictly controlled, attention still affected feature integration. The results indicate that orienting attention to the location of the cue affects the quality of the perceptual representation for features and their integration.     

Is apparent instability a guiding feature in visual search?

ABSTRACT

Humans are quick to notice if an object is unstable. Does that assessment require attention or can instability serve as a preattentive feature that can guide the deployment of attention? This paper describes a series of visual search experiments, designed to address this question. Experiment 1 shows that less stable images among more stable images are found more efficiently than more stable among less stable; a search asymmetry that supports guidance by instability. Experiment 2 shows efficient search but no search asymmetry when the orientation of the objects is removed as a confound. Experiment 3 independently varies the orientation cues and perceived stability and finds a clear main effect of apparent stability. Experiment 4 shows converging evidence for a role of stability using different stimuli that lack an orientation cue. However, here both search for stable and unstable targets is inefficient. Experiment 5 is a control for Experiment 4, showing that the stability effect in Experiment 4 is not simple side-effects of the geometry of the stimuli. On balance, the data support a role for instability in the guidance of attention in visual search. (184 words)     

Aging and visual search: Generalized cognitive slowing or selective deficit in attention?

Abstract

Selective attention in normal aging was investigated using simple and conjoined feature visual search tasks. the effects of varying the location of the target (central vs. peripheral, left vs. right hemifield) and the complement of distractors, together with variability in task performance across subject groups, were also examined. the findings indicated that the feature extraction stage of visual search was preserved in older aged subjects. However, there was a differential age-related impairment in the feature integration stage of visual processing in the two older groups (66-75 years, 76-85 years). This was greater than the magnitude of decline predicted on the basis of generalized cognitive slowing. There was no evidence of a speed-accuracy trade-off in the performance of either search task. the findings of this study contribute towards the delineation of age-dependent and -independent processes subserving visual selective attention. the performance of older individuals may be relatively well preserved on more automatic, less demanding tasks such as simple feature search. By contrast, there may be differential age-related impairments on visual search tasks such as conjoined feature search, which may require more effortful or controlled attentional processing.     

Are nominal same-different matches slower due to differences in level of processing or to response competition?

Eriksen, O’Hara, and Eriksen (1982) have proposed that the latency advantage ofsame overdifferent judgments when the match is based upon physical identity is due to differential amounts of response competition between the responses by which the judgment ofsame ordifferent is signified. Responses of “different” are slowed by a high level of priming in the competing response signifyingsame. In the present experiment, the response competition model is extended to nominal matches and in particular to what Proctor 1198D has termed the “name-physieal disparity”—a pair of letters are more rapidly judged to have the same name if they are the same ease (e.g., a a) than if they are in different eases (e.g., A a). While response competition effects were found to occur in nominal matches of this kind, the name-physieal disparity was greater than could be attributed solely to response competition. Evidence was obtained that part of the name-physieal disparity could be attributed to the subject’s having two chances to make a-nominal raatch when the letter pair was identical both physically and in name. The match could be made either on the basis of the physical or the name code. It was assumed that name and physical codes were processed at least partially independently.     

Implicit learning: A way to improve visual search in spatial neglect?

Studies have shown that neglect patients are able to use stimulus regularities to orient faster toward the neglected side, without necessarily being aware of that information, or at the very least without being able to verbalize their knowledge. In order to better control for the involvement of explicit processes, the present study sought to test neglect patients’ ability to detect more complex associations between stimuli using tasks similar to those used in implicit learning studies. Our results demonstrate that neglect patients had difficulties implicitly learning complex associations, contrary to what we found with controls. The possible influence of attentional and working memory impairments are discussed.     

Does training under consistent mapping conditions lead to automatic attention attraction to targets in search tasks?

Schneider and Shiffrin (1977) proposed that training under consistent stimulus-response mapping (CM) leads to automatic target detection in search tasks. Other theories, such as Treisman and Gelade's (1980) feature integration theory, consider target-distractor discriminability as the main determinant of search performance. The first two experiments pit these two principles against each other. The results show that CM training is neither necessary nor sufficient to achieve optimal search performance. Two other experiments examine whether CM trained targets, presented as distractors in unattended display locations, attract attention away from current targets. The results are again found to vary with target-distractor similarity. Overall, the present study strongly suggests that CM training does not invariably lead to automatic attention attraction in search tasks.     

Are there age differences in attention to emotional images following a sad mood induction? Evidence from a free-viewing eye-tracking paradigm

Two experiments examined age differences in the effect of a sad mood induction (MI) on attention to emotional images. Younger and older adults viewed sets of four images while their eye gaze was tracked throughout an 8-s presentation. Images were viewed before and after a sad MI to assess the effect of a sad mood on attention to positive and negative scenes. Younger and older adults exhibited positively biased attention after the sad MI, significantly increasing their attention to positive images, with no evidence of an age difference in either experiment. A test of participants’ recognition memory for the images indicated that the sad MI reduced memory accuracy for sad images for younger and older adults. The results suggest that heightened attention to positive images following a sad MI reflects an affect regulation strategy related to mood repair. The implications for theories of the positivity effect are discussed.     

Amodal completion in visual search: preemption or context effects?

In a previous study, search for a notched-disk target abutting a square among complete-disk nontargets and squares was inefficient in 250-ms exposures, but relatively efficient in 100-ms exposures. This finding was interpreted as evidence that amodal completion proceeds through a mosaic and then a completion stage, with the latter preempting the former. We used the same target but changed its context: Nontargets were instead notched disks near squares. Task set was also different: Participants searched for a complete disk. Contrary to the prediction of the preemption model, search was efficient in the 100-ms condition and inefficient in the 250-ms condition. We propose that in both the present and the previous studies, the target was ambiguous, and task set and context affected how it was perceived. In both experiments, set effects were evident for 100-ms exposures; context effects were evident for 250-ms exposures.     

Are verbal transformations sensitive to age differences and stimulus properties?

Verbal transformations are illusory changes that arise from listening to a spoken word repeated over and over for a prolonged period of time. Past research has yielded some evidence of age differences in participants' reports of verbal transformations. The goal of the present study was to examine reports of illusory percepts in young and older adults to determine whether participant characteristics (i.e., age, cognitive integrity, hearing acuity, vocabulary knowledge, and mood) and differences in sensitivity to properties of the stimulus material could account for age-related declines in reports of illusory changes. We observed age-related declines in new forms (illusory percepts) but merely a trend in the same direction for transitions (changes from the veridical sensory experience to illusory percepts and reversals to either the veridical sensory experience or other percepts). There was no evidence that participant characteristics other than age accounted for reports of illusory changes. However, we found age differences in participants' sensitivity to properties of the stimulus material: Young adults but not older adults were sensitive to the frequency of the veridical percepts. In contrast, both age groups were sensitive to the size of the neighborhood of similar-sounding words. These findings are discussed regarding the transmission deficit hypothesis (MacKay & Burke, 1990).     

Precue effects in visual search: Data or resource limited?

Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability (d′) of a target at that location. This is often attributed to the observer’s increased allocation of some limited cognitive resource (“attention”) to the cued location. Two experiments are reported which are difficult to interpret in this way even though they involve similar cue effects. The first involves postcuing a location well after the array but before the observer responds, so that the cue can influence the response but not the observation. The second involves precuing, but with slow sequential presentation of array elements prior to the response, so the observer need not share any limited resource while processing each element in turn. Enhanced detectability similar to that produced with precues and simultaneous presentation of elements is shown to occur in each experiment. An alternative data-limited (rather than resource-limited) interpretation of these effects is provided by a mathematical model in which the observer integrates equally noisy or degraded internal representations of the array elements, but gives more weight to cued elements in selecting a response. Theoretical parameters of the model are shown to provide separate measures of both an observer’s overall sensitivity and precue effects in cost-benefit analyses of cuing data.     

Do multielement visual tracking and visual search draw continuously on the same visual attention resources?

Multielement visual tracking and visual search are 2 tasks that are held to require visual-spatial attention. The authors used the attentional operating characteristic (AOC) method to determine whether both tasks draw continuously on the same attentional resource (i.e., whether the 2 tasks are mutually exclusive). The authors found that observers can search and track within the same trial significantly better than would be predicted if the 2 tasks were mutually exclusive. In fact, the AOC for tracking and search is similar to that for tracking and auditory monitoring. The results of additional experiments support an attention-switching account for this high level of dual-task performance in which a single attentional resource is efficiently switched between the tracking and search. The results provide important constraints for architectures of visual selective attention and the mechanisms of multielement tracking.     

Sex differences in neural efficiency: Are they due to the stereotype threat effect?

The neural efficiency hypothesis postulates a more efficient use of brain resources in more intelligent people as compared to less intelligent ones. However, this relationship was found to be moderated by sex and task content. While the phenomenon of neural efficiency was previously supported for men when performing visuo-spatial tasks it occurred for women only when performing verbal tasks. One possible explanation for this finding could be provided by the well-studied phenomenon called stereotype threat. Stereotype threat arises when a negative stereotype of one’s own group is made salient and can result in behavior that confirms the stereotype. Overall, 32 boys and 31 girls of varying intellectual ability were tested with a mental rotation task, either under a stereotype exposure or a no-stereotype exposure condition while measuring their EEG. The behavioral results show that an activated negative stereotype not necessarily hampers the performance of girls. Physiologically, a confirmation of the neural efficiency phenomenon was only obtained for boys working under a no-stereotype exposure condition. This result pattern replicates previous findings without threat and thus suggests that sex differences in neural efficiency during visuo-spatial tasks may not be due to the stereotype threat effect.     

Were you paying attention to where you looked? The role of executive working memory in visual search

Recent evidence has indicated that performing a working memory task that loads executive working memory leads to less efficient visual search (Han & Kim, 2004). We explored the role that executive functioning plays in visual search by examining the pattern of eye movements while participants performed a search task with or without a secondary executive working memory task. Results indicate that executive functioning plays two roles in visual search: the identification of objects and the control of the disengagement of attention.     

Do threatening stimuli draw or hold visual attention in subclinical anxiety?

Biases in information processing undoubtedly play an important role in the maintenance of emotion and emotional disorders. In an attentional cueing paradigm, threat words and angry faces had no advantage over positive or neutral words (or faces) in attracting attention to their own location, even for people who were highly state-anxious. In contrast, the presence of threatening cues (words and faces) had a strong impact on the disengagement of attention. When a threat cue was presented and a target subsequently presented in another location, high state-anxious individuals took longer to detect the target relative to when either a positive or a neutral cue was presented. It is concluded that threat-related stimuli affect attentional dwell time and the disengage component of attention, leaving the question of whether threat stimuli affect the shift component of attention open to debate.     

Are there age-related differences in learning to optimize speed, accuracy, and energy expenditure?

Studies of age-related differences in manual aiming have indicated that older adults take longer to complete their movements than their younger counterparts because they tend to rely on time-consuming feedback-based control processes. Many authors have suggested that the reliance on feedback is the result of a "play-it-safe" strategy that has been adopted to compensate for a deterioration in accurate and consistent force generation. That is, perhaps because older adults know that their motor systems are not as reliable as the systems were at a younger age, they plan shorter movements that conserve time and space for feedback control to correct their programmed actions. The vast majority of the previous studies that have revealed these age-related differences in aiming, however, have used computer-based tasks that involve the transformation of perceptual into motor space. In the present experiment, older and younger adults completed real aiming movements over three sessions. The results suggest that, when acting in a real environment, the main difference between older and younger adults in movement execution lies in the efficient use of response-related feedback, not in the programming of movement.     

Are attentional dwell times inconsistent with serial visual search?

Duncan, Ward, and Shapiro (1994) estimated that attention must remain focused on an object for several hundred milliseconds before being shifted to another object, and they referred to this period as theattentional dwell time. An important implication of these long estimates of the dwell time for models of visual search is that the search process must not involve an item-by-item serial scanning mechanism. If it did, then searching through an array of items would require enormous amounts of time, which—based on data from visual search experiments—it does not. The present report, however, provides evidence that the long estimates of attentional dwell time were caused, at least in part, by the use of masked targets. Implications of these variable estimates of the attentional dwell time for models of visual search are discussed.     

Is time to scan visual images due to demand characteristics?

The time to scan across an object in a mental image increases with the distance scanned. Does this finding reflect the operation of underlying mechanisms or the effects of demand characteristics? Two types of demand characteristics were considered here. First, the scanning effects were shown to persist even when they conflicted with the experimenters' expectations. Experimenters were led to expect different rates of scanning and different effects of distance on scan times, but the results in all cases showed no hint of experimenter effects, instead displaying the usual increase in time with distance scanned. Second, the scanning effects were shown to persist in the absence of implicit task demands. Effects of distance were observed in an experiment in which subjects were never asked to scan the image; furthermore, such effects were observed only for items that should require spontaneous scanning even though they were randomly intermixed with items that should not, and this distinction was never mentioned nor alluded to in the instructions. Thus, experimenter effects and task demands are not sufficient explanations for the increase in the time to scan across an image as distance is increased.     

Are there gender differences in cognitive reflection? Invariance and differences related to mathematics

ABSTRACT

Cognitive reflection is recognized as an important skill, which is necessary for making advantageous decisions. Even though gender differences in the Cognitive Reflection test (CRT) appear to be robust across multiple studies, little research has examined the source of the gender gap in performance. In Study 1, we tested the invariance of the scale across genders. In Study 2, we investigated the role of math anxiety, mathematical reasoning, and gender in CRT performance. The results attested the measurement equivalence of the Cognitive Reflection Test – Long (CRT- L), when administered to male and female students. Additionally, the results of the mediation analysis showed an indirect effect of gender on CRT-L performance through mathematical reasoning and math anxiety. The direct effect of gender was no longer statistically significant after accounting for the other variables. The current findings suggest that cognitive reflection is affected by numerical skills and related feelings.     

Are summary statistics enough? Evidence for the importance of shape in guiding visual search

Peripheral vision outside the focus of attention may rely on summary statistics. We used a gaze-contingent paradigm to directly test this assumption by asking whether search performance differed between targets and statistically-matched visualizations of the same targets. Four-object search displays included one statistically-matched object that was replaced by an unaltered version of the object during the first eye movement. Targets were designated by previews, which were never altered. Two types of statistically-matched objects were tested: One that maintained global shape and one that did not. Differences in guidance were found between targets and statistically-matched objects when shape was not preserved, suggesting that they were not informationally equivalent. Responses were also slower after target fixation when shape was not preserved, suggesting an extrafoveal processing of the target that again used shape information. We conclude that summary statistics must include some global shape information to approximate the peripheral information used during search.