Visual attention and the perception of features and objects.

Feature integration theory (Treisman & Gelade, 1980) suggested that simple features are coded in parallel in a number of specialized feature maps, but that focussed attention is required to ensure the correct integration of features to specify objects. This is done by a serial scan through a master-map of locations, giving access to the features currently occupying the attended location. These are then integrated to form a representation of the object in the selected location. The present paper reviewed new evidence that has accrued since 1980 and elaborated the model to accommodate the recent findings. The proposal is that four different mechanisms may be involved in different conditions: selection of locations, directed by an externally controlled window of attention; selection by features through preattentive grouping; selection of objects; and selection for access to responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention and objects: Evidence for hierarchical coding of location.

In 5 experiments, it was found that judging the relative location of 2 contours was more difficult when they belonged to 2 objects rather than 1. This was observed even when the 1- and 2-object displays were physically identical, with perceptual set determining how many objects they were seen to contain. Such a 2-object cost is consistent with object-based views of attention and with a hierarchical scheme for position coding, whereby object parts are located relative to the position of their parent object. In further experiments, it was shown that in accord with this hierarchical scheme, the relative location of objects could disrupt judgments of the relative location of object parts, but the reverse did not occur. This was found even when the relative position of the parts could be judged more quickly than that of the objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case for inhibition: Visual attention suppresses the processing of irrelevant objects.

The present study investigated the ability to inhibit the processing of an irrelevant visual object while processing a relevant one. Participants were presented with 2 overlapping shapes (e.g., circle and square) in different colors. The task was to name the color of the relevant object designated by shape. Congruent or incongruent color words appeared in the relevant object, in the irrelevant object, or in the background. Stroop effects indicated how strong the respective area of the display was processed. The results of 4 experiments showed that words in the relevant object produced larger Stroop effects than words in the background, indicating amplification of relevant objects. In addition, words in the irrelevant object consistently produced smaller Stroop effects than words in the background, indicating inhibition of irrelevant objects. Control experiments replicated these findings with brief display durations (250 ms) and ruled out perceptual factors as a possible explanation. In summary, results support the notion of an inhibitory mechanism of object-based attention, which can be applied in addition to the amplification of relevant objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention and objects: One versus two or convex versus concave?

According to object-based theories of visual attention, attention can be divided within a single object more efficiently than between separate objects (J. Duncan, 1984). Recently, G. C. Baylis and J. Driver (1993) provided a theoretical framework for interpreting this single-object advantage within the domain of spatial organization. Using their hierarchical coding of location hypothesis, they showed that the latency to compare the location of 2 vertices was significantly faster for vertices that were seen as parts of a single (convex) object than for vertices that were seen as parts of separate (concave) objects. This article reports the replication of this finding, as well as new evidence that shows that latency is affected by the convexity of the contour, and not by the number of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic attention does not equal automatic fear: Preferential attention without implicit valence.

Theories of nonassociative fear acquisition hold that humans have an innate predisposition for some fears, such as fear of snakes and spiders. This predisposition may be mediated by an evolved fear module (?hman & Mineka, 2001) that responds to basic perceptual features of threat stimuli by directing attention preferentially and generating an automatic fear response. Visual search and affective priming tasks were used to examine attentional processing and implicit evaluation of snake and spider pictures in participants with different explicit attitudes; controls (n = 25) and snake and spider experts (n = 23). Attentional processing and explicit evaluation were found to diverge; snakes and spiders were preferentially attended to by all participants; however, they were negative only for controls. Implicit evaluations of dangerous and nondangerous snakes and spiders, which have similar perceptual features, differed for expert participants, but not for controls. The authors suggest that although snakes and spiders are preferentially attended to, negative evaluations are not automatically elicited during this processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention and stimulus identification.

Previous research has provided evidence for parallel stimulus processing in visual search tasks; however, it has frequently been noted that detecting prespecified targets might be accomplished without actually identifying targets and/or distractors. In the present 5 experiments, with 61 university students, a novel task was employed to require exhaustive identification. In this task, Ss named the highest digit in an array. RTs and display size effects in this task were strikingly similar to those obtained in conventional search tasks. Manipulation of display size and visual quality was used to test predictions of serial and parallel encoding models. Display size was additive with 2 different visual quality factors in the highest digit task, a finding that argues against serial execution of the corresponding stages. Interactions with decision-related factors suggest that visual quality may have affected the rate of character recognition, not just feature extraction. Thus, results strengthen the case for parallel (though perhaps capacity-limited) identification of multiple familiar stimuli. It is pointed out that parallel identification need not entail late selection, and some alternative possibilities are suggested. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual priming of inverted and rotated objects.

[Correction Notice: An erratum for this article was reported in Vol 36(4) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2010-12650-021). In the article, there was an error in the sixth sentence of the abstract. The sentence should read “Experiments 2 and 3 demonstrated that although identification was sensitive to orientation, visual priming was relatively invariant with image inversion (i.e., an image visually primed its inverted counterpart approximately as much as it primed itself).”] Object images are identified more efficiently after prior exposure. Here, the authors investigated shape representations supporting object priming. The dependent measure in all experiments was the minimum exposure duration required to correctly identify an object image in a rapid serial visual presentation stream. Priming was defined as the change in minimum exposure duration for identification as a function of prior exposure to an object. Experiment 1 demonstrated that this dependent measure yielded an estimate of predominantly visual priming (i.e., free of name and concept priming). Experiments 2 and 3 demonstrated that although priming was sensitive to orientation, visual priming was relatively invariant with image inversion (i.e., an image visually primed its inverted counterpart approximately as much as it primed itself). Experiment 4 demonstrated a similar dissociation with images rotated 90° off the upright. In all experiments, the difference in the magnitude of priming for identical or rotated–inverted priming conditions was marginal or nonexistent. These results suggest that visual representations that support priming can be relatively insensitive to picture-plane manipulations, although these manipulations have a substantial effect on object identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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, with a total of 22 university students. Peripheral cues were used in Exp 1, and central cues were used in Exps 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention to arrays of multidimensional objects.

Encoding briefly displayed arrays of multidimensional objects appears to require selective attention, but this hypothesis is challenged by M. J. Nissen's (1985) finding that properties of an object are reported independently. Selective attention to some objects but not others should produce positive dependence. Theoretical analysis shows that deviations from independence would have been difficult to observe in Nissen's data because of high guessing rates and small sample sizes. Four new experiments showing strong positive dependence in property reports are described. Deviations from independence were highly significant for most Ss. Quantitative modeling shows that selective attention to subsets of objects would produce about the amount of dependence obtained. Rather than challenging attention theories, the amount of dependence in encoding multidimensional objects is consistent with selective attention to either objects or locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gaze cueing of attention: Visual attention, social cognition, and individual differences.

During social interactions, people's eyes convey a wealth of information about their direction of attention and their emotional and mental states. This review aims to provide a comprehensive overview of past and current research into the perception of gaze behavior and its effect on the observer. This encompasses the perception of gaze direction and its influence on perception of the other person, as well as gaze-following behavior such as joint attention, in infant, adult, and clinical populations. Particular focus is given to the gaze-cueing paradigm that has been used to investigate the mechanisms of joint attention. The contribution of this paradigm has been significant and will likely continue to advance knowledge across diverse fields within psychology and neuroscience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation between infants' activity with objects and attention to object appearance.

The authors examined the relation between infants' motor skills and attention to objects features in events in which a hand acted on an object (e.g., squeezed it) that then produced a sound (e.g., squeaking). In this study, 6- to 7-month-old infants (N = 41) were habituated to a single event and then tested with changes in appearance and action. Infants robustly responded to changes in action, but as a group did not respond to changes in appearance. Moreover, more skilled activity with objects during naturalistic play was associated with longer looking in response to a change in appearance, but not to a change in action. Implications for the relation between perception and action in infancy are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Switching attention within and between objects: The role of subjective organization.

Provided a direct assessment of object-based allocation of attention through comparing different Ss' responses to the same stimulus patterns under different perceptual organizations. Eight undergraduates participated in each of 4 experiments. Exps 1A and 1B employed 2-object stimulus patterns to evaluate attention switching within and between objects while equating the number of intervening contours across conditions. Exps 2A and 2B used the same stimulus patterns, but varied the Ss perceptual organization such that these patterns were perceived as 1 object rather than 2. An object effect was found if a stimulus pattern was seen as a single object. The study provides converging evidence to the existence of multiple levels of visual representations. It suggests that attention selects the internal representation of both space and the object, and that subjective organization is an important factor in the manifestation of the object effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention in HIV-1 infection.

27 nondemented HIV-seropositive men and 13 seronegative controls performed 2 versions of a spatial attention task that engaged either automatic or controlled attentional processing. Ss also performed a 3rd task requiring divided attention, which tested for potential deficits in attentional resources. HIV-seropositive symptomatic Ss were impaired on the automatic processing task, whereas asymptomatic Ss performed the task normally compared with controls. In contrast, no differences were observed among the 3 groups on the controlled attention task. However, both seropositive groups showed deficits on the divided attention task. These results suggest that deficits in selective attention are present early in the course of HIV-1 infection. The most prominent impairment is seen on tasks that are highly demanding of attentional resources, whereas deficits in automatic processing develop later in the disease process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual marking: Prioritizing selection for new objects by top-down attentional inhibition of old objects.

The authors propose a new mechanism for prioritizing the selection of new events: visual marking. In a modified conjunction search task the authors presented one set of distractors before the remaining items, which contained the target if present. Search was as efficient as if only the second items were presented. This held when eye movements were prevented and required a gap of 400 ms between the old and new items. The effect was abolished by luminance changes at old distractor locations when the new items appeared, and it was reduced by the addition of an attention demanding load task. The authors propose that old items can be ignored by spatially parallel, top-down attentional inhibition applied to the locations of static stimuli. The authors discuss the relations between marking and other accounts of visual selection and potential neurophysiological mechanisms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Visual marking: Selective attention to asynchronous temporal groups.

In visual search, when a subset of distractors is previewed 1 s before the target and the remaining distractors, search speed is independent of the number of previewed items. This is visual marking. What allows old items to be marked? Four experiments show that marking is disrupted if the onset of the new items is accompanied by synchronous changes to the old items, but it is not disrupted by changes restricted to the background or by asynchronous changes to the old items. Further, behaviorally relevant old items can be prioritized over new items. Visual marking is based on temporal asynchrony between new and old items, which allows segregation of these items into 2 temporal groups. Attention is then selectively applied to 1 group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual information about time-to-collision between two objects.

Evaluated human observers' sensitivity to visual information specifying a moving object's future time of arrival at a designated position in the field of view in a forced-choice paradigm. A geometrical analysis demonstrated that information specifying a 1st-order temporal relationship (i.e., without taking changes in velocity into account) is available in the combination of the relative rate of dilation of the optical contour of the moving object and the relative rate of constriction of the optical gap separating the moving object from the target position. Observers were sensitive to information contained in the relative rate of constriction of the optical gap if no contour dilation component was present and to the combination of information contained in the relative rates of dilation of the optical contour of the moving object and constriction of the optical gap if both were present albeit with a differential weighting of the 2 components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory objects of attention: The role of interaural time differences.

The role of interaural time difference (ITD) in perceptual grouping and selective attention was explored in 3 experiments. Experiment 1 showed that listeners can use small differences in ITD between 2 sentences to say which of 2 short, constant target words was part of the attended sentence, in the absence of talker or fundamental frequency differences. Experiments 2 and 3 showed that listeners do not explicitly track components that share a common ITD. Their inability to segregate a harmonic from a target vowel by a difference in ITD was not substantially changed by the vowel being placed in a sentence context, where the sentence shared the same ITD as the rest of the vowel. The results indicate that in following a particular auditory sound source over time, listeners attend to perceived auditory objects at particular azimuthal positions rather than attend explicitly to those frequency components that share a common ITD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual memory for novel shapes: Implicit coding without attention.

Implicit memory for novel shapes was explored with a negative priming paradigm. The results show that representations of shapes, formed in a single trial and without attention, can last without decrement across 200 intervening trials and with temporal delays of up to a month. No explicit memory of the shapes was available, either immediately or after a delay. There were consistent individual differences in the amount of negative priming shown, and some participants showed only facilitation. There was a trend toward increased facilitation across time, as if the memory of the shape survived longer than an "action tag" attached to it, which specified whether it should be attended or ignored. The results demonstrate a surprising combination of plasticity and permanence in the visual system and suggest that the roles of both attention and repetition may be to ensure voluntary retrievability rather than to form a lasting memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual word recognition without central attention: Evidence for greater automaticity with advancing age.

The present experiments examined the automaticity of word recognition. The authors examined whether people can recognize words while central attention is devoted to another task and how this ability changes across the life span. In Experiment 1, a lexical decision Task 2 was combined with either an auditory or a visual Task 1. Regardless of the Task 1 modality, Task 2 word recognition proceeded in parallel with Task 1 central operations for older adults but not for younger adults. This is a rare example of improved cognitive processing with advancing age. When Task 2 was nonlexical (Experiment 2), however, there was no evidence for greater parallel processing for older adults. Thus, the processing advantage appears to be restricted to lexical processes. The authors conclude that greater cumulative experience with lexical processing leads to greater automaticity, allowing older adults to more efficiently perform this stage in parallel with another task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)