Attention: Reaction Time and Accuracy Reveal Different Mechanisms.

The authors propose that there are 2 different mechanisms whereby spatial cues capture attention. The voluntary mechanism is the strategic allocation of perceptual resources to the location most likely to contain the target. The involuntary mechanism is a reflexive orienting response that occurs even when the spatial cue does not indicate the probable target location. Voluntary attention enhances the perceptual representation of the stimulus in the cued location relative to other locations. Hence, voluntary attention affects performance in experiments designed around both accuracy and reaction time. Involuntary attention affects a decision as to which location should be responded to. Because involuntary attention does not change the perceptual representation, it affects performance in reaction time experiments but not accuracy experiments. The authors obtained this pattern of results in 4 different versions of the spatial cuing paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of return to negative emotion: Evidence from an emotional expression detection task.

After the presentation of an uninformative spatial cue, it usually takes participants more time to respond to a target that appears at the cued location when the interval between the cue and target is long. This phenomenon is named inhibition of return (IOR), implying that returning attention to the cued location is inhibited because of attentional disengagement. The present study investigated whether irrelevant emotional information is processed by the attentional system in a similar manner. Uninformative positive and negative emotional cues were presented at the center of the screen, and faces were presented as the target. An emotional expression detection task was used to reveal the inhibitory and facilitatory aftereffects of the attentional processing of the emotional cues. An emotion-based IOR effect on reaction time was observed only after the presence of a negative emotional cue, implying that the attentional system tends to inhibit irrelevant negative emotion but not inhibit irrelevant positive emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatiotemporal distribution of facilitation and inhibition of return arising from the reflexive orienting of covert attention.

Currently, there is debate regarding both the spatial and temporal relationship between facilitation and inhibition of return (IOR) components of attention, as observed on the covert orienting of visual attention task (COVAT). These issues were addressed in a series of experiments where the spatial and temporal relationships between cue and target were manipulated. Facilitation occurred only when the stimulus onset asynchrony (SOA) was short and there was temporal overlap between cue and target. IOR occurred only when SOA was long and there was no temporal overlap between cue and target. Facilitation encompassed the cued location and all locations between the cue and fixation, whereas IOR arose for the entire cued hemifield. These findings suggest that the facilitation and IOR found on COVATs that use noninformative peripheral cues are separable and stimulus-driven processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When cross-modal spatial attention fails.

There is now convincing evidence that an involuntary shift of spatial attention to a stimulus in one modality can affect the processing of stimuli in other modalities, but inconsistent findings across different paradigms have led to controversy. Such inconsistencies have important implications for theories of cross-modal attention. The authors investigated why orienting attention to a visual event sometimes influences responses to subsequent sounds and why it sometimes fails to do so. They examined visual-cue-on-auditory-target effects in two paradigms--implicit spatial discrimination (ISD) and orthogonal cuing (OC)--that have yielded conflicting findings in the past. Consistent with previous research, visual cues facilitated responses to same-side auditory targets in the ISD paradigm but not in the OC paradigm. Furthermore, in the ISD paradigm, visual cues facilitated responses to auditory targets only when the targets were presented directly at the cued location, not when they appeared above or below the cued location. This pattern of results confirms recent claims that visual cues fail to influence responses to auditory targets in the OC paradigm because the targets fall outside the focus of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual load modulates object-based attention.

Two experimental series are reported using both reaction time (RT) and a data-limited perceptual report to examine the effects of perceptual load on object-based attention. Perceptual load was manipulated across 3 levels by increasing the complexity of perceptual judgments. Data from the RT-based experiments showed object-based effects when the target was near the cued location. Results from the data-limited procedure showed that, with low perceptual load, attention spread along the cued object, supporting an object-based attention account. As load increased, attention was constrained to object locations near the cue, but attention still favored the cued object, inconsistent with a scanning prioritization account of object-based attention effects. Furthermore, findings showed that perceptual load modulates object selection in a manner similar to spatial attention, suggesting that there might be a common process underlying object-based and spatial attention. (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)     

Inhibition of return to successively cued spatial locations.

Inhibition of return refers to a bias against returning attention to a location that has been recently attended. Experiments are reported that examined inhibition of return to multiple exogenously cued spatial locations. When 2 peripheral locations were cued in succession, inhibition was found for only the 1 most recently cued location. In addition, more inhibition occurred at the location of the most recent cue if the earlier cue had also been presented there, as compared with an earlier cue at a different location. Thus, the magnitude of the inhibition for a location appears to depend on the effectiveness of the attentional cue to that location. Other results suggest that candidate locations for inhibition are displaced by subsequent cues—they do not simply decay. The results provide an initial framework within which to study inhibition of return to multiple spatial locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exogenous orienting does not reflect an encapsulated set of processes.

It is widely assumed that orienting attention by the use of exogenous cues reflects an encapsulated system impervious to linguistic influence. This view was assessed in 4 experiments in which observers made discriminations between target characters presented above or below fixation. The spatial location of the target was cued by the abrupt onset of a word that was semantically related to a word at fixation on half of the trials and unrelated on the remainder. Responses were significantly faster when target location was validly cued than when it was not. More important, the magnitude of this cuing effect varied as a function of whether the abrupt-onset word cue was semantically related to the fixation word. These results suggest that linguistic processing influences the process of disengagement or movement (or both) from the cued location. Visuospatial attention as reflected in the exogenous-cuing paradigm does not depend on an encapsulated set of processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new component of visual orienting: Implicit effects of peripheral information and subthreshold cues on covert attention.

Four experiments examined effects of peripheral cue stimuli on covert spatial attention. In Experiment 1 target stimuli were preceded by a pair of bilaterally presented cue letters. The relative location of the cues predicted target location (left or right), but participants were not informed of this. After a brief practice period, visual orienting was influenced by the letter cues. This implicit peripheral cuing effect was unrelated to participants' awareness of the cue-target relationship. Experiments 2 and 3 showed that visual orienting may occur independently of both perceptual awareness of the peripheral cue event itself and contingency awareness concerning the cue–target relation. Experiment 4 demonstrated that implicit peripheral cuing is qualitatively distinct from voluntary orienting. These findings are discussed in relation to work on spatial attention, implicit learning, and perception without awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory localization for spatial orientation

The use of three-dimensional auditory technology that provides localization of auditory cues presented through headphones is proposed as a means of providing supplemental information to pilots on the spatial orientation of an aircraft. This technique shows promise for reducing accidents due to spatial disorientation associated with high visual load. A study was conducted using United States Air Force pilots as subjects to determine desirable? cue characteristics for accurately localizing auditory cues using this technique. The study examined the use of 9 different cue types at each of 2 frequency levels. It was found that the accuracy of subjects' localization of cues in elevation was greatly enhanced by the use of multidimensional cues that provided redundant elevation information through varying frequencies and distance from the horizon cues in addition to the inherent spatial location information. Trade-offs in azimuth localization accuracy and response time were noted, however. Recommendations are made for further developing and investigating this technique for the aircraft spatial orientation task.     

Effect of same- and different-modality spatial cues on auditory and visual target identification.

A target identification paradigm was used to study cross-modal spatial cuing effects on auditory and visual target identification. Each trial consisted of an auditory or visual spatial cue followed by an auditory or visual target. The cue and target could be either of the same modality (within-modality conditions) or of different modalities (between-modalities conditions). In 3 experiments, a larger cue validity effect was apparent on within-modality trials than on between-modalities trials. In addition, the likelihood of identifying a significant cross-modal cuing effect was observed to depend on the predictability of the cue-target relation. These effects are interpreted as evidence (a) of separate auditory and visual spatial attention mechanisms and (b) that target identification may be influenced by spatial cues of another modality but that this effect is primarily dependent on the engagement of endogenous attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneity of dendritic cells in human superficial lymph node: in vitro maturation of immature dendritic cells into mature or activated interdigitating reticulum cells

A target identification paradigm was used to study cross-modal spatial cuing effects on auditory and visual target identification. Each trial consisted of an auditory or visual spatial cue followed by an auditory or visual target. The cue and target could be either of the same modality (within-modality conditions) or of different modalities (between-modalities conditions). In 3 experiments, a larger cue validity effect was apparent on within-modality trials than on between-modalities trials. In addition, the likelihood of identifying a significant cross-modal cuing effect was observed to depend on the predictability of the cue-target relation. These effects are interpreted as evidence (a) of separate auditory and visual spatial attention mechanisms and (b) that target identification may be influenced by spatial cues of another modality but that this effect is primarily dependent on the engagement of endogenous attentional mechanisms.     

Is Posner's "beam" the same as Treisman's "glue?" On the relation between visual orienting and feature integration theory.

In the present study we investigated whether the visually allocated "beam" studied by Posner and others is the same visual attentional resource that performs the role of feature integration in Treisman's model. Subjects were cued to attend to a certain spatial location by a visual cue, and performance at expected and unexpected stimulus locations was compared. Subjects searched for a target letter (R) with distractor letters that either could give rise to illusory conjunctions (PQ) or could not (PB). Results from three separate experiments showed that orienting attention in response to central cues (endogenous orienting) showed similar effects for both conjunction and feature search. However, when attention was oriented with peripheral visual cues (exogenous orienting), conjunction search showed larger effects of attention than did feature search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective processing of visual alcohol cues in abstinent alcoholics: an approach-avoidance conflict?

When symptomatic individuals selectively attend to emotionally relevant stimuli, the ability to shift attention away from such material is impaired. Subjects may, however, seek to avoid further processing of these stimuli, which would facilitate attentional shifts. This was examined in a group of abstinent alcoholics' responses to stimuli related to alcohol. Eight alcohol and eight neutral words served as cues in a covert attention task. The cues were either valid (2/3 of trials) or invalid (1/3 of trials) indicators of where a response target would appear after 100 or 500 milliseconds. The short interval was expected to interact with an initial approach toward the alcohol word, while the long interval would interact with a subsequent avoidance of the stimulus. As predicted, the alcoholics showed slower reaction times (RTs) to targets invalidly cued by alcohol words in the short interval, reflecting increased difficulties to shift attention. However, the alcoholics demonstrated faster RTs to targets invalidly cued by the alcohol words in the long interval. This indicates that the alcohol cue elicited emotional associations that, subsequent to initial stimulus identification, trigger an interrupting function of the attentional system.     

The effects of nicotine on spatial and non-spatial expectancies in a covert orienting task

The present study examined how nicotine influences shifts of visuo spatial attention in casual smokers at each of three delays after smoking one cigarette: immediately, 1 h and 24 h. Informative peripheral cues were used to exogenously orient attention to the location where an increase or decrease in the size of a peripheral object was most likely to occur. One size change was more likely to occur than the other and the task was choice (expansion/contraction) reaction time. The performance decrement obtained when the target appeared at an uncued location was smallest in sessions run immediately after smoking (when nicotine levels were highest), suggesting that nicotine may increase the ease with which attention can be disengaged from a cued location. This finding confirms previous research which suggests a specific role for the basal forebrain cholinergic system in visual orienting. In contrast, nicotine was not found to affect non-spatial expectancies based on stimulus-response (expansion/contraction) probability. These findings, together with recent converging evidence, strongly support the proposition that different attentional operations are mediated by different neural subsystems.     

Contingent attentional capture by top-down control settings: Converging evidence from event-related potentials.

Theories of attentional control are divided over whether the capture of spatial attention depends primarily on stimulus salience or is contingent on attentional control settings induced by task demands. The authors addressed this issue using the N2-posterior- contralateral (N2pc) effect, a component of the event-related brain potential thought to reflect attentional allocation. They presented a cue display followed by a target display of 4 letters. Each display contained a green item and a red item. Some participants responded to the red letter and others to the green letter. Converging lines of evidence indicated that attention was captured by the cues with the same color as the target. First, these target-color cues produced a cuing validity effect on behavioral measures. Second, distractors appearing in the cued location produced larger compatibility effects. Third, the target-color cue produced a robust N2pc effect, similar in magnitude to the N2pc effect to the target itself. Furthermore, the target-color cue elicited a similar N2pc effect regardless of whether it competed with a simultaneous abrupt onset. The findings provide converging evidence for attentional capture contingent on top-down control settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral and computational models of spatial attention.

Pigeons pecked for food in a spatially cued choice reaction time (RT) task. A brief (50-msec) white light appeared on a left or right key and probabilistically predicted the location (on either the left or right key) of a subsequent target stimulus. The time between cue and target onset (stimulus onset asynchrony), the base rate of left cues, and the probability that the cue correctly predicted the target (cue validity) were experimentally varied. The mean RT to respond to the target key was faster on correctly cued trials (defining a validity effect), decreased for both valid and invalid trials as stimulus onset asynchrony increased (defining an alerting effect), showed a variety of base-rate effects, and did not depend on cue validity. It is shown with a computational-processing model that dynamic interactions of short-term and associative memory processes are sufficient to produce these attention-like empirical phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining the role of the fixation cue in inhibition of return.

To clarify the role of the fixation cue in inhibition of return (IOR), the present study compared four conditions: fixation cue immediately after the peripheral cue, in the middle of the stimulus-onset asynchrony (SOA), immediately before the onset of the target, or no fixation cue. With a 200-ms SOA, less IOR was found when the fixation cue was either absent or occurred immediately after the peripheral cue. No differences between the four conditions were found with 400-ms and 800-ms SOAs. These findings suggest that there is a brief period of time in which attention cannot be withdrawn from the peripherally cued location. Once attention has been withdrawn from the peripherally cued location, IOR can be found at short SOAs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical and temporal scaling considerations in a robot model of cricket calling song preference

The cerebellum has been implicated in higher cognitive functions including learning, memory, and attention as well as its well-known role in motor programming. Recent studies have suggested that the cerebellum plays a role in shifts of attention. We investigated the contribution of the cerebellum to visuospatial attentional ability in a trial-by-trial cueing task involving the covert orienting of spatial attention. We recorded event-related evoked potentials (ERPs) and reaction times (RTs) in patients with cerebellar degenerative disorders affecting mainly the lateral cerebellum and compared them to age-matched controls. The RT data demonstrated that both the cerebellar patients and control subjects responded to the valid cues faster than to the invalid cues for both the central and the peripheral cues. Consistent with the RT data, the ERP data showed a comparable generation of attention shift-related negativities during the cue-target interval for both the central and the peripheral cue experiments. The early negative component of the ERP to the target was also comparably modulated in both groups as a function of cue validity, suggesting efficient facilitation of sensory pathways by prior allocation of spatial attention to the cued place. Conversely, the late negative deflection preceding the imperative target stimulus and the late sustained positivity following target presentation, which reflect neural activities for response preparation and selection, were reduced in the cerebellar group. These findings suggest that the lateral cerebellum makes little contribution to visuospatial attention shift in either the voluntary or automatic modes and support a role of the lateral cerebellum in the neural system required for response preparation and selection.     

Interactive Activation in Visual Word Recognition: Constraints Imposed by the Joint Effects of Spatial Attention and Semantics.

Two lexical-decision experiments investigated the effects of semantic priming and stimulus intensity when target location varied and was cued by an abrupt onset. In Experiment 1, the spatial cue was a good predictor of target location, and in Experiment 2 it was not. The results indicate that word recognition processes were postponed until spatial attention was focused on the target and that whether attention further affected word recognition depended on cue validity. The joint effects of cue validity and priming interacted when cue validity was high but were additive when cue validity was low. The joint effects of stimulus intensity and semantic priming also varied according to cue validity (i.e., interactive when high and additive when low). The results are discussed in terms of their implications for visual word recognition, the distinction between exogenous and endogenous spatial attention, and how attention is affected by visual word recognition processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)