Exogenous/Endogenous Control of Space-based/ Object-based Attention: Four Types of Visual Selection?

Phasic pupillary responses modulate object-based attentional prioritization

Visual attention studies have demonstrated that the shape of space-based selection can be governed by salient object contours: when a portion of an enclosed space is cued, the selected region extends to the full enclosure. Although this form of object-based attention (OBA) is well established, one continuing investigation focuses on whether this selection is obligatory or under voluntary control. We attempt to dissociate between these alternatives by interrogating the locus coeruleus-norepinephrine (LC-NE) system – known to fluctuate with top-down attention – during a classic two-rectangle paradigm in a sample of healthy human participants (N = 36). An endogenous spatial pre-cue directed voluntary space-based attention (SBA) to one end of a rectangular frame. We manipulated the reliability of the cue, such that targets appearing at an uncued location within the frame occurred at low or moderate frequencies. Phasic pupillary responses time-locked to the cue display served to noninvasively measure LC-NE activity, reflecting top-down processing of the spatial cue. If OBA is controlled analogously to SBA, then object selection should emerge only when it is behaviorally expedient and when LC-NE activity reflects a high degree of top-down attention to the cue display. Our results bore this out. Thus, we conclude that OBA was voluntarily controlled, and furthermore show that phasic norepinephrine may modulate attentional strategy.

Steps to Health in Cognitive Aging: Effects of Physical Activity on Spatial Attention and Executive Control in the Elderly

The purpose of this study was to investigate whether physical activity (PA) habits may positively impact performance of the orienting and executive control networks in community-dwelling aging individuals and diabetics, who are at risk of cognitive dysfunction. To this aim, we tested cross-sectionally whether age, ranging from late middle-age to old adulthood, and PA level independently or interactively predict different facets of the attentional performance. Hundred and thirty female and male individuals and 22 adults with type 2 diabetes aged 55–84 years were recruited and their daily PA (steps) was objectively measured by means of armband monitors. Participants performed a multifunctional attentional go/no-go reaction time (RT) task in which spatial attention was cued by means of informative direct cues of different sizes followed by compound stimuli with local and global target features. The performance efficiency of the orienting networks was estimated by computing RT differences between validly and invalidly cued trials, that of the executive control networks by computing local switch costs that are RT differences between switch and non-switch trials in mixed blocks of global and local target trials. In regression analyses performed on the data of non-diabetic elderlies, overall RTs and orienting effects resulted jointly predicted by age and steps. Age predicted overall RTs in low-active individuals, but orienting effects and response errors in high-active individuals. Switch costs were predicted by age only, with larger costs at older age. In the analysis conducted with the 22 diabetics and 22 matched non-diabetic elderlies, diabetic status and daily steps predicted longer and shorter RTs, respectively. Results suggest that high PA levels exert beneficial, but differentiated effects on processing speed and attentional networks performance in aging individuals that partially counteract the detrimental effects of advancing age and diabetic status. In conclusion, adequate levels of overall PA may positively impinge on brain efficiency and attentional control and should be therefore promoted by actions that support lifelong PA participation and impact the built environment to render it more conducive to PA.

Spatial distribution of attentional bias in visuo-spatial working memory following multiple cues

When attention is focused on one location, its spatial distribution depends on many factors, such as the distance between the attended location and the target location, the presence of visual meridians in between them, and the way, endogenous or exogenous, by which attention is oriented. However, it is not well known how attention distributes when more than one location is endogenously or exogenously cued, which was the focus of the current study. Furthermore, the distribution of attention has been manly investigated in perception. In the present study we faced this issue from a different perspective, by examining the spatial distribution of the attentional bias in visuo-spatial working memory (VSWM), when attention is oriented either exogenously or endogenously, i.e., after two peripheral vs. central symbolic cues (also manipulating cue-target predictability). Results indicated a systematic difference between endogenous and exogenous attention regarding the distribution of the attentional bias over VSWM. In fact, attentional bias following endogenous cues was affected by the presence of visual meridians and by the split of the attentional focus, converging in a unipolar attentional distribution, independently of cue-target predictability. On the other hand, when pulled by exogenous cues, attention distributed uni-modally or multi-modally depending on the distance between the cued locations, with larger effects for highly predictive cues. Results are discussed in terms of space-based, object-based and perceptual grouping mechanisms.

Signal evaluation environment: a new method for the design of peripheral in-vehicle warning signals

An evaluation method called the Signal Evaluation Environment (SEE) was developed for use in the early stages of the design process of peripheral warning signals while driving. Accident analyses have shown that with complex driving situations such as intersections, the visual scan strategies of the driver contribute to overlooking other road users who have the right of way. Salient peripheral warning signals could disrupt these strategies and direct drivers' attention towards these road users. To select effective warning signals, the SEE was developed as a laboratory task requiring visual-cognitive processes similar to those used at intersections. For validation of the SEE, four experiments were conducted using different stimulus characteristics (size, colour contrast, shape, flashing) that influence peripheral vision. The results confirm that the SEE is able to differentiate between the selected stimulus characteristics. The SEE is a useful initial tool for designing peripheral signals, allowing quick and efficient preselection of beneficial signals.

Focusing of visual attention at rest and during physical exercise in soccer players

In this study, we investigated the focus of visual attention in expert soccer players together with the effects of acute bouts of physical exercise on performance. In two discriminative reaction time experiments, which were performed both at rest and under submaximal physical workload, visual attention was cued by means of spatial cues of different size followed by compound stimuli with local and global target features. Soccer players were slower than non-athletes in reacting to local compared with global targets, but were faster in switching from local to global attending. Thus, soccer players appear to be less skilled in local attending, but better able than non-athletes to rapidly "zoom out" the focus of attention. Non-athletes generally showed faster performance under physical load, as expected according to the hypothesis of exercise-induced increases in arousal and/or activation and in resource allocation. In contrast, soccer players showed a more differentiated pattern of exercise-induced facilitation that selectively affects specific components of the attentional performance and is interpreted by referring to the role played by individual expertise and cognitive effort.

Selective Working Memory Disables Inhibition of Visual Features

Abstract. Recent research suggests that information held in working memory can facilitate subsequent attentional processing. Here, we explore the negative corollary of this conception: Under which circumstances does information in working memory disrupt subsequent processing? Seventy participants performed visual discriminations in a dual-task paradigm. They were asked to judge colors or shapes in an online attention task under three different working-memory conditions: Same, Switch, or Unknown. In the Same condition, participants selectively maintained one visual feature in working memory, from the same dimension as in the online attention task. In the Switch condition, participants selectively maintained one visual feature in working memory, but had to focus on another visual dimension in the online attention task. In the Unknown condition, participants could not predict which visual feature would be relevant for the working-memory task. We found that irrelevant features in the online attention task were particularly difficult to ignore in the Switch condition, that is, when the irrelevant features belong to a visual dimension that is simultaneously prioritized in selective working memory. The findings are consistent with accounts in terms of neural overlap between working-memory and attention circuits, and suggest that mechanisms of selection, rather than resource limitations, critically determine the extent of visual interference.

Effects of aging on visual attentional focusing

BACKGROUND

Visual attentional performance is affected by aging, but there are methodological barriers to the understanding of this phenomenon that are due, above all, to the concomitant deterioration of sensory or central factors such as visual acuity and information processing speed.

OBJECTIVE

The aim of the present study was to verify the effects of aging on visual attentional focusing by analyzing the space- and object-based components as well as the exogenous and endogenous dimensions of the attentional allocation.

METHODS

Focusing of visual attention was investigated in 14 youngsters, 14 younger adults and 14 older adults (age ranges 12-15, 24-38 and 60-75 years, respectively). In two discrimination reaction time (RT) experiments, attention was cued by means of spatial cues of different size followed by compound stimuli at a shorter (150 ms) and a longer (500 ms) stimulus-onset asynchrony (SOA). The compound stimuli contained a predefined target letter at a local or global level.

RESULTS

Older adults showed generally slower RTs and higher rates of delayed responses than younger individuals and reduced discrimination speed of local objects at 150-ms SOA, particularly when attention was invalidly cued to focus at a larger spatial scale.

CONCLUSIONS

This pattern of results suggests that aging causes a dysfunction of the space-based and the object-based components of the attentional 'zooming in'. Such information may be of practical relevance for developing attentional training programs for older adults.

Aufmerksamkeitsbasiertes Wahrnehmungstraining zur taktischen Entscheidungsschulung im Fußball

Zusammenfassung. In dieser Studie wurde der Einfluss eines videobasierten Trainings von Wahrnehmung und Aufmerksamkeit auf taktische Entscheidungsprozesse im Fußball überprüft. Der Versuchsplan folgte einem varianzanalytischen Messwiederholungsdesign mit vier Gruppen (drei unterschiedliche Trainingsprogramme und eine Kontrollgruppe) und drei Messzeitpunkten (Prä-, Post- und Retentionstest). An der Studie nahmen 62 Jugendspieler (C- und B-Jugend) im Alter von 14.32 (SD = 1.10) Jahren teil. Das Testprogramm bestand für alle vier Gruppen aus 51 Videosequenzen, die ebenso wie die Trainingsvideos mit der temporal occlusion Technik bearbeitet wurden und “3 gegen 2” Situationen abbildeten. Zwei Trainingsgruppen absolvierten jeweils ein videobasiertes Trainingsprogramm, das insgesamt 210 Videosequenzen sowie 210 Feedbackvideos beinhaltete. Der Unterschied zwischen diesen beiden Gruppen bestand darin, dass eine Gruppe innerhalb des gleichen Programms mit in die Sequenzen implementierten Aufmerksamkeitslenkern visuell manipuliert wurde. Die dritte Trainingsgruppe trainierte praktisch auf dem Feld. Die Kontrollgruppe erhielt kein Treatment. Die Ergebnisse belegen, dass videobasiertes Wahrnehmungstraining im Rahmen taktischer Entscheidungsprozesse zu signifikanten Verbesserungen in den Reaktionszeiten führt. Bezüglich der Manipulation der Aufmerksamkeitsausrichtung in den Videotrainingsprogrammen konnte kein signifikanter Einfluss auf die abhängigen Variablen nachgewiesen werden.

Crosstalk between on-line and off-line processing of visual features

Three dual-task experiments were conducted to investigate the relation between immediate, "on-line" judgments about visual features and delayed, "off-line" judgments. One hypothesis ("selective interference") predicted that dual-task performance would be challenged specifically within a visual dimension, as both tasks compete for the same resources. Another hypothesis ("cost of switching") made the opposite prediction. In Experiment 1, participants performed either color or shape discriminations in the on-line and off-line visual tasks, with systematic variation of feature similarity between the on-line and off-line features. In Experiment 2, participants performed either color or shape discriminations in the off-line task and color discriminations in the on-line task, with no overlap between the on-line and off-line features. In Experiment 3, participants performed color discriminations in both the on-line and off-line tasks, with partially overlapping stimulus sets. Altogether, the data from the three experiments provided evidence in favor of the hypothesis of cost of switching. Stimulus-stimulus compatibility effects between features in the off-line task and those in the on-line task further underscored the perceptual nature of the crosstalk.

Modulation of object-based attention by spatial focus under endogenous and exogenous orienting

In R. Egly, J. Driver, and R. D. Rafal's (1994) influential double-rectangle spatial-cuing paradigm, exogenous cues consistently induce object-based attention, whereas endogenous cues generally induce space-based attention. This difference suggests an interdependency between mode of orienting (endogenous vs exogenous) and mode of selection (object based vs space based). However, mode of orienting is generally confounded with initial focus of attention: Endogenous orienting begins with attention focused on a central cue, whereas exogenous orienting begins with attention widely spread. In this study, an attentional-focusing hypothesis is examined and supported by experiments showing that for both endogenous and exogenous cuing, object-based effects are obtained under conditions that encourage spread attention, but they are attenuated under conditions that encourage focused attention. General implications for object-based attention are discussed. ((c) 2003 APA, all rights reserved)

Does the perception of moving eyes trigger reflexive visual orienting in autism?

Does movement of the eyes in one or another direction function as an automatic attentional cue to a location of interest? Two experiments explored the directional movement of the eyes in a full face for speed of detection of an aftercoming location target in young people with autism and in control participants. Our aim was to investigate whether a low-level perceptual impairment underlies the delay in gaze following characteristic of autism. The participants' task was to detect a target appearing on the left or right of the screen either 100 ms or 800 ms after a face cue appeared with eyes averting to the left or right. Despite instructions to ignore eye-movement in the face cue, people with autism and control adolescents were quicker to detect targets that had been preceded by an eye movement cue congruent with target location compared with targets preceded by an incongruent eye movement cue. The attention shifts are thought to be reflexive because the cue was to be ignored, and because the effect was found even when cue-target duration was short (100 ms). Because (experiment two) the effect persisted even when the face was inverted, it would seem that the direction of movement of eyes can provide a powerful (involuntary) cue to a location.

Rapid, object-based learning in the deployment of transient attention

We show that transient attention summoned by an exogenous cue shows rapid learning of the relationship between the cue and a subsequent target in a discrimination task. In experiment 1, performance was unaffected when a target always appeared in the same position on a large cue, but was degraded when the target could appear anywhere within the extent of the larger cue. Experiment 2 shows that it was not the predictability of where the target appeared within the cue that aided performance, but rather a consistent location mapping of cue and target, since predictably alternating the target location relative to the cue led to worse performance than when the target was presented in the same location relative to the cue from trial to trial. Further analysis of the results of experiment 2 shows that the learning is rapid, evident after one trial, and has a cumulative influence over four consecutive trials. Possible neural correlates of this form of learning are discussed, with a focus on the supplementary eye fields in the prefrontal cortex. The reported experiments show that transient attention is not a simple reflexive mechanism but can show rapid visuospatial learning, in object-based coordinates.

Focusing of Visuospatial Attention

Abstract In the present study we explored the focusing of visuospatial attention in subjects practicing and not practicing activities with high attentional demands. Similar to the studies of Castiello and Umiltà (e. g., 1990) , our experimental procedure was a variation of Posner's (1980) basic paradigm for exploring covert orienting of visuospatial attention. In a simple RT-task, a peripheral cue of varying size was presented unilaterally or bilaterally from a central fixation point and followed by a target at different stimulus-onset-asynchronies (SOAs). The target could occur validly inside the cue or invalidly outside the cue with varying spatial relation to its boundary. Event-related brain potentials (ERPs) and reaction times (RTs) were recorded to target stimuli under the different task conditions. RT and ERP findings showed converging aspects as well as dissociations. Electrophysiological results revealed an amplitude modulation of the ERPs in the early and late Nd time interval at both anterior and posterior scalp sites, which seems to be related to the effects of peripheral informative cues as well as to the attentional expertise. Results were: (1) shorter latency effects confirm the positive-going amplitude enhancement elicited by unilateral peripheral cues and strengthen the criticism against the neutrality of spatially nonpredictive peripheral cueing of all possible target locations which is often presumed in behavioral studies. (2) Longer latency effects show that subjects with attentional expertise modulate the distribution of the attentional resources in the visual space differently than nonexperienced subjects. Skilled practice may lead to minimizing attentional costs by automatizing the use of a span of attention that is adapted to the most frequent task demands and endogenously increases the allocation of resources to cope with less usual attending conditions.

Allocating attention in the visual field: the effects of cue type and target-distractor confusability

In the present study I compared the effect of colour and location cues on the selection of a target. Two questions were in focus. First, can both colour and location cues trigger and mediate attentional selection, and if they can, which of them is more effective? Second, does physical distinctiveness between a target and a distractor have to be taken into account? In two experiments, in which the most likely target colour or location was cued, both colour cues and arrow-like location cues produced cue-validity effects. The relative effectiveness of feature cues and location cues appeared, to some extent, to be dependent on target-distractor confusability. Taken together, the results support the post-categorical filter theory, in which different cues can be used to trigger the feedback loop that is used to address relevant identity information via location.

Global orientation disrupts the detection of a similar local orientation

Two experiments were carried out with organised displays in order to examine the role of similarity between global and local orientation in visual search. In both experiments, distractors were organised to form a diagonal line of plus or minus 45 degrees. In experiment 1, target displays were presented tachistoscopically. Participants searched for a target letter 'Q' among distractor letters 'O'. In experiment 2, participants performed a heterogeneity task with target line segments that could have an orientation of either plus or minus 45 degrees. The target appeared partly or completely inside a distractor circle. In both experiments, the target was more difficult to detect when the critical feature aligned with the slope of the global diagonal than when the feature did not align. Taken together, the two experiments suggested a sequential global-to-local processing in which the orientation of the global figure disrupts the detection of a similar local orientation.