Mental curve tracing with elementary stimuli.

It has been proposed that certain spatial relations are determined by an operation, or "visual routine," that can trace along a boundary (Ullman, 1984), as supported by Jolicoeur, Ullman, & Mackay's (1986) finding that the time required to determine if 2 Xs are on the same curve increased monotonically with the separation of the Xs along that curve. In the present study the generality of the curve tracing hypothesis was explored across 4 experiments by using elementary stimuli that eliminated interweaving curves, displaced the fixation point away from the curves and target Xs, and provided a simple alternative to curve tracing—namely, determining whether or not the Xs fell on the same side of the figure. In Exps 1 and 2, Ss were instructed to decide if the 2 Xs fell on same or different curves. Mean reaction time (RT) for same trials increased monotonically with the distance separating the Xs. In Exps 3 and 4 alternatives to curve tracing were tested. For same trials the evidence strongly favored curve tracing. However, different trials were apparently solved on the basis of judgmental processes operating in parallel with curve tracing. Curve tracing rates fluctuated across experiments and seemed to be partially governed by the width of the "pathway" provided for the trace. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Manipulating the shape of distance effects in visual curve tracing: Further evidence for the zoom lens model.

Reexamined the predictive power of the zoom lens curve tracing model in the research of P. A. McCormick and P. Jolicoeur (see record 1992-07800-001) by selectively manipulating distractor proximity in 4 conditions and regressing the predictions of the model on human response time. 12 university students participated. The model was compared with 2 other curve tracing models: pixel by pixel tracing and the bipartite receptive field operator of Jolicoeur et al (see record 1992-15217-001). Results provide strong support for McCormick and Jolicoeur's visual attention based zoom lens operator. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory and visual capture during focused visual attention.

It is well known that auditory and visual onsets presented at a particular location can capture a person’s visual attention. However, the question of whether such attentional capture disappears when attention is focused endogenously beforehand has not yet been answered. Moreover, previous studies have not differentiated between capture by onsets presented at a nontarget (invalid) location and possible performance benefits occurring when the target location is (validly) cued. In this study, the authors modulated the degree of attentional focus by presenting endogenous cues with varying reliability and by displaying placeholders indicating the precise areas where the target stimuli could occur. By using not only valid and invalid exogenous cues but also neutral cues that provide temporal but no spatial information, they found performance benefits as well as costs when attention is not strongly focused. The benefits disappear when the attentional focus is increased. These results indicate that there is bottom-up capture of visual attention by irrelevant auditory and visual stimuli that cannot be suppressed by top-down attentional control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic contextual cuing and visual attention.

Since M. M. Chun and Y. Jiang's (1998) original study, a large body of research based on the contextual cuing paradigm has shown that the visuocognitive system is capable of capturing certain regularities in the environment in an implicit way. The present study investigated whether regularities based on the semantic category membership of the context can be learned implicitly and whether that learning depends on attention. The contextual cuing paradigm was used with lexical displays in which the semantic category of the contextual words either did or did not predict the target location. Experiments 1 and 2 revealed that implicit contextual cuing effects can be extended to semantic category regularities. Experiments 3 and 4 indicated an implicit contextual cuing effect when the predictive context appeared in an attended color but not when the predictive context appeared in an ignored color. However, when the previously ignored context suddenly became attended, it immediately facilitated performance. In contrast, when the previously attended context suddenly became ignored, no benefit was observed. Results suggest that the expression of implicit semantic knowledge depends on attention but that latent learning can nevertheless take place outside the attentional field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention and the organization of visual information.

Conducted 4 experiments with 108 volunteers (aged 18-42 yrs) to test object-, discrimination-, and space-based theories of visual attention. In each experiment, Ss were presented with small (     

A theory of visual attention.

A unified theory of visual recognition and attentional selection is developed by integrating the biased-choice model for single-stimulus recognition (R. D. Luce, 1963; R. N. Shepard, 1957) with a choice model for selection from multielement displays (C. Bundesen et al; see record 1985-05669-001) in a race model framework. Mathematically, the theory is tractable, and it specifies the computations necessary for selection. The theory is applied to extant findings from a broad range of experimental paradigms. The findings include effects of object integrality in selective report, number and spatial position of targets in divided-attention paradigms, selection criterion and number of distracters in focused-attention paradigms, delay of selection cue in partial report, and consistent practice in search. On the whole, the quantitative fits are encouraging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Splitting visual space with attention.

The present study aimed at showing a spatial compatibility effect (and, by implication, a right–left subdivision of space) solely attributable to the orienting of attention. Five groups of 8 normal Ss were required to give right–left discriminative responses to stimuli presented within one of 6 empty boxes arranged in a horizontal row. Reaction times and errors were recorded. A right–left grouping of the boxes occurred regardless of whether Ss' fixation was kept at the intermediate position (Exp 1) or at one extremity (Exp 2) of the row. In Exps 3 and 4, Ss' attention was not aligned with a fixed position but was moved, through peripheral cues, from trial to trial and positioned between different pairs of adjacent boxes. Results showed that the display was again subdivided into 2 regions and that the reference point for the right–left subdivision was the focus of attention. In Exp 5, eye position was instrumentally monitored, and Ss' attention was directed by central cues. The results confirmed that the focusing of attention leads to a right–left partitioning of space. Directing attention to a position in space brings about a right–left perceptual organization that predominates over that provided by the other egocentric reference axes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allocation of attention in the visual field.

Investigated in 2 experiments whether attentional resources can be simultaneously allocated to several locations in a visual display, whether the mode of processing (serial or parallel) can be switched within a trial, and the nature of the costs when attentional resouces are concentrated on an invalid location. In each of the experiments, 6 college students were required to determine which of 2 target letters was present in 8-letter circular displays. In precue conditions, a primary and a secondary target location were designated 150 msec before target onset by an indicator that varied in validity. In the control conditions no cue was provided. Exp II verified several assumptions that had been made in interpreting the data of Exp I. Modifications in J. Jonides's (see record 1984-08558-001) 2-process model are suggested in terms of a zoom lens model of attentional resources. Instead of 2 alternative processing modes, attentional resources are seen as capable of distribution over the visual field, but with low resolving power, or as continuously constricting to small portions of the visual field with a concomitant increase in processing power. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention in the primate visual system.

A series of single unit PET and behavioural studies is described addressing the functions and neurophysiology of visual attention. Beyond striale cortex, visual information is processed in a network of separate cortical areas, specialized in part for analysis of different visual attributes. Issues arising in such a modular system include the nature of the attentional state in extrastriate cortex, its flexible control by the requirements of current behaviour, and the coordination between areas implied by attention to whole objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the spatial distribution of visual attention.

A reanalysis of part of P. Podgorny and R. N. Shepard's (see record 1984-03057-001) data shows that reaction times (RTs) to attended and unattended squares are almost identical when the attended areas are nonunitary and that RTs are related to compactness for unitary attended areas but that this relation breaks down when attention is focused on nonunitary areas. The importance of the actual grid location of probes on RTs is also illustrated. The failure of compactness to reflect these aspects of the spatial nature of attention suggests that this metric is deficient when applied to the study of the spatial determinants of attention. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and shifts of visual spatial attention.

Three experiments examined adult age differences in the efficiency of endogenous (voluntary) and exogenous (involuntary) attention shifts. Younger and older Ss performed a spatial cuing task in which abruptly onset peripheral cues (Exp 1) or central, symbolic cues (Exps 2 and 3) were presented before a target stimulus at intervals ranging from 50 to 250 msec. With peripheral cues, the magnitude of cuing effects was at least as great for older as for younger adults and followed a similar time course. Similar results were obtained with symbolic cues, although cuing effects for older adults varied with cue difficulty. The results suggest that cue encoding may decline with advancing age but that the efficiency of the shift process is preserved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measuring and modeling the trajectory of visual spatial attention.

In a novel choice attention-gating paradigm, observers monitor a stream of 3x3 letter arrays until a tonal cue directs them to report 1 row. Analyses of the particular arrays from which reported letters are chosen and of the joint probabilities of reporting pairs of letters are used to derive a theory of attention dynamics. An attention window opens 0.15 s following a cue to attend to a location, remains open (minimally) 0.2 s, and admits information simultaneously from all the newly attended locations. The window dynamics are independent of the distance moved. The theory accounts for about 90% of the variance from the over 400 data points obtained from each of the observers in the 3 experiments reported here. With minor elaborations, it applies to all the principal paradigms used to study the dynamics of visual spatial attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Multiple parallel access in visual attention.

Argues that the single focus of attention, generally assumed to represent the allocation of processing resources, does not totally explain how spatially local information is accessed in the visual field (VF). It is suggested that even if attention is unitary and spatially focused, there is also a more primitive mechanism for simultaneously indexing several places in a VF, thus individuating these places and making them directly accessible for further processing. Considerations suggesting the need for a multiple-locus indexing mechanism are discussed. Empirical evidence for particular properties (multiple-object tracking, cued search, subitizing, and illusory line motion) of the indexing mechanism is reviewed. Evidence suggests that there is an early preattentive stage in vision where a small number of salient items in the VF are indexed and thereby made readily accessible for a variety of visual tasks. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probability matching in visual selective attention.

J. Jonides (see record 1981-22746-001) suggested a model to account for shifts of spatial attention in visual search tasks with less than 100% cue validity. This 2-stage probability matching model was subsequently tested by Jonides (see record 1984-08558-001). Reaction time (RT) distribution characteristics provided some support for the model. The present author reanalyzes Jonides's data (including that published in 1981). Analysis showed strong support for the probability matching hypothesis. It is concluded that probability matching is an important strategic characteristic of visual spatial attention. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial maps of directed visual attention.

Previous studies have shown that simple reaction times (RTs) to a visual target are facilitated when the target occurs at a location expected by an observer and are slowed when the target occurs at the mirror-symmetric location contralateral to the expectancy. The present 7 experiments, with 8 observers, examined the spatial extent of this attention effect by inducing Ss to expect the target at 1 location and introducing occasional probe flashes at other locations throughout the visual field. RTs to these probes were equivalent to those obtained at the expected location so long as the probe was in the same hemifield as the S's expectancy. Conversely, RTs to probes in the hemifield opposite the expectancy generated uniformly slower response times. These results were obtained when the expected location varied in eccentricity from 2° to 16° along the horizontal meridian. In addition, when the expected and unexpected locations were within the same hemifield, no expectancy effects were observed. Under these conditions, the frequently used metaphor that directed visual attention operates like a spatially restricted "beam" appears inaccurate. Implications for current views of directed attention are considered. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal contextual cuing of visual attention.

Previous research has shown how spatial attention is guided to a target location, but little is understood about how attention is allocated to an event in time. The authors introduce a paradigm to manipulate the sequential structure of visual events independent of responses. They asked whether this temporal context could be implicitly learned and used to guide attention to a relative point in time or location, or both, in space. Experiments show that sequentially structured event durations, event identities, and spatiotemporal event sequences can guide attention to a point in time as well as to a target event's identity and location. Cuing was found to rely heavily on the element immediately preceding the target, although cuing from earlier items also was evident. Learning was implicit in all cases. These results show that the sequential structure of the visual world plays an important role in guiding visual attention to target events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation of the visual cortex in motivated attention.

Functional activation (measured with fMRI) in occipital cortex was more extensive when participants view pictures strongly related to primary motive states (i.e., victims of violent death, viewer-directed threat, and erotica). This functional activity was greater than that observed for less intense emotional (i.e., happy families or angry faces) or neutral images (i.e., household objects, neutral faces). Both the extent and strength of functional activity were related to the judged affective arousal of the different picture contents, and the same pattern of functional activation was present whether pictures were presented in color or in grayscale. It is suggested that more extensive visual system activation reflects "motivated attention," in which appetitive or defensive motivational engagement directs attention and facilitates perceptual processing of survival-relevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and the scope of visual attention

OBJECTIVE: To discover whether some cognitive deficits associated with aging could be related to a restricted scope of visual attention. DESIGN: Cross-sectional study, with subjects in each age group receiving the same four conditions. Subjects: 24 elderly (mean age 65.2 years, 12 men and 12 women) and 24 young (mean age 21.8 years, 12 men and 12 women) matched for handedness, gender, and education level. METHODS: Subjects viewed a display that contained four light-gray squares arranged as if on the tips of a plus sign, then black X marks appeared and the subjects indicated whether one or two Xs appeared in the squares as quickly and accurately as possible. The time to respond and accuracy level were recorded. Two types of displays were used; one with squares spread out over a large area and one with squares condensed into a small area. In two thirds of the trials the size remained the same (with half being large, and half small), and in one third it changed (with half of these trials changing from large-to-small and half from small-to-large). RESULTS: In the trials that had a consistent display size, the elderly subjects performed the task better with the smaller display, whereas the young subjects performed equally well with both sized displays. In addition, the elderly found it easier to shift from large to small scope than to maintain attention at the large scope; in contrast, the younger subjects found it easiest to maintain attention on a static display size. CONCLUSIONS: The elderly prefer to focus attention on a smaller region of space than do younger people.     

The relationship between visual attention and eye movements.

Experimental psychologists have recently amassed a great deal of evidence supporting the hypothesis that the visual system can select a particular location over other locations in the visual field for further analysis without overtly orienting the eyes to the selected location. At the same time, we know that during reading and scene perception, the eyes are overtly directed to new regions of the visual field every 200 to 300 msec on average. How are covert shifts of attention and overt movements of the eyes related during complex visual-cognitive tasks? The available evidence from studies of the perceptual span in reading suggests that attention is allocated asymmetrically around the fixation point, with more information acquired in the direction that the eyes are moving. Based on this evidence and evidence from explorations of eye movement control in reading, the author presents a tentative model of the relationship between attention and eye movements, called the Sequential Attention Model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Systematic analysis of deficits in visual attention.

A variety of impairments in visual attention can follow damage to the brain. The authors develop systematic methods for analyzing such impairments in terms of C. Bundesen's (see record 1991-03287-001) Theory of Visual Attention and apply these in a group of 9 patients with parietal lobe lesions and variable spatial neglect. In whole report, patients report letters from brief, vertical arrays in left or right visual field. The results show substantial, largely bilateral impairments in processing capacity, implying a major nonlateralized aspect to neglect. In partial report, arrays contain 1 or 2 letters in red and/or green. The task is to report only those letters in a specified target color. In addition to the expected bias against left-sided letters, patients show striking, bilateral preservation of top-down control, or attentional priority for targets. The results show how differentiation of attentional impairments can be informed by a theory of normal function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)