Attention effects of abrupt-onset precues with central, single-element, and multiple-element precues

Endogenous and exogenous processes of attention have been inferred with different types of precues used in allocation of attention to a target location. In the present research, a comparison was made between the typical peripheral single-element precue (SEP), a central precue, and a multiple-element precue (MEP) in order to further understanding of the processes involved in allocation of attention. Two precues were used on each trial in these experiments. An abrupt-onset precue appeared with an SEP, an MEP, or a central precue and was followed 50 or 300 ms later by a screen containing a target and two distractor characters. The abrupt-onset precue and the other precue each could be valid or invalid in indicating the location of the target, as in the study by Juola, Koshino, and Warner (1995). Response times to the targets showed that validity effects of the abrupt-onset precue and the MEP or central precue were additive, whereas those of the abrupt-onset precue and the SEP were interactive. These data suggest that, like a central precue, an MEP is an endogenous precue that guides conscious control of attention and has its attentional effects at a different processing level from an SEP, which is an exogenous precue and may compete for attentional resources with an abrupt-onset precue.     

Allocation of visual attention depends on type of precue

To distinguish between theoretical concepts of how attention is allocated, participants were presented with different types of precues in 6 experiments. In 1 condition with 100% valid precues (Experiments 1 and 2), the time course of attention effects revealed that (a) higher accuracy was obtained with dynamic multiple-element precues (MEPs in which the unique element was defined by apparent motion) than with static MEPs, in which the elements did not move once they were presented (Cheal & Chastain, 1998); (b) a longer precue-target interval (stimulus-onset asynchrony; SOA) was needed to reach asymptote accuracy with dynamic MEPs than with dynamic single-element precues (SEPs); and (c) all dynamic precues (both MEPs and SEPs) resulted in a decline in accuracy at long SOAs. These results suggest that static and dynamic MEPs result in delayed engagement of attention relative to SEPs. Further, a decline in accuracy at long intervals is associated with static and dynamic SEPs and dynamic MEPs, but not with static MEPs. With irrelevant precues (Experiments 3 to 5), there was capture by precues in which the unique element moved briskly, smoothly, or abruptly, or simply flashed on and off, although there were differences in the amount of capture. The strongest capture occurred with smooth movement in static background elements and the weakest with smooth movement in abruptly moving background elements. It was shown in Experiment 6 that a static MEP will not capture attention if one element changes to a unique brightness near the time of precue onset, but if the element changes after 1,000 ms, it will capture attention. The authors suggest that different types of precues result in unequal influence of endogenous and exogenous components of attention, even when the same targets are used. In addition, they show that neither singleton detection mode nor contingent involuntary orienting is necessary for the capture of attention.     

Exogenous and endogenous control of attention: the effect of visual onsets and offsets

Two experiments were carried out to investigate the relation between exogenous and endogenous control of visual attention. Subjects searched for a target letter among three nontarget letters that were positioned on an imaginary circle around a fixation point. At different cue-display intervals, a centrally located arrowhead cue reliably indicated the location of the target letter. At different SOAs, a peripheral line segment near one of the letters was either abruptly switched on (Experiment 1) or abruptly switched off (Experiment 2). Presenting the central arrowhead after display onset prevents attention from being focused in advance on the critical location. In this unfocused attentional state, both onset and offset transients attracted attention. When the central arrowhead was available in advance, the focusing of attention prior to display onset precluded attention attraction to the location of the onset or offset transient. Contrary to an offset transient, an onset transient presented at the attended location disrupted performance, indicating that an onset within the spotlight of attention attracts attention. The results are reconciled by means of the zoom-lens theory of attention, suggesting that outside the focus of attention, abrupt transients are not capable of attracting attention. Since the size of the zoom lens is under voluntary control, it can be argued that transients do not fulfill the intentionality criterion of automaticity.     

Involuntary covert orienting is contingent on attentional control settings.

Four experiments tested a new hypothesis that involuntary attention shifts are contingent on the relationship between the properties of the eliciting event and the properties required for task performance. In a variant of the spatial cuing paradigm, the relation between cue property and the property useful in locating the target was systematically manipulated. In Experiment 1, invalid abrupt-onset precues produced costs for targets characterized by an abrupt onset but not for targets characterized by a discontinuity in color. In Experiment 2, invalid color precues produced greater costs for color targets than for abrupt-onset targets. Experiment 3 provided converging evidence for this pattern. Experiment 4 investigated the boundary conditions and time course for attention shifts elicited by color discontinuities. The results of these experiments suggest that attention capture is contingent on attentional control settings induced by task demands.     

Spatial Stroop and spatial orienting: the role of onset versus offset cues

The present study investigated whether offset cues have the same attentional consequences in the spatial Stroop effect as onset cues. Experiments 1 and 2 compared the attentional effects of onset–offset cues versus offset cues on the spatial Stroop effect, whereas Experiment 3 compared the attentional effects of onset versus offset cues. Across these experiments, independent of cue type (onset–offset or onset vs. offset) and even at long stimulus-onset asynchrony, attentional cueing did not revert into inhibition of return and was modulated by spatial Stroop with greater cueing effects for incongruent arrow’s direction and position. In addition, onset–offset or onset and offset cues produced comparable cueing effects in the location-direction congruent condition, and onset–offset or onset cues produced greater facilitation than offset cues in the incongruent condition. From a different perspective, peripheral cueing modulated the spatial Stroop effect in the same direction for onset–offset or onset and offset cues, although the reduction in spatial Stroop at cued locations was smaller with offset than with onset–offset or onset cues.     

A developmental study of attention to auditory and visual signals

Three experiments tested for developmental changes in attention to simple auditory and visual signals. Subject pressed a single button in response to the onset (Experiment 1) or offset (Experiment 2) of either a tone or a light. During one block of trials subjects knew which stimulus would come on or go off on each trial (precue condition) whereas during the other block of trials no precue was provided. In both experiments subjects as young as 4 years old responded more rapidly with precues, indicating that they were able to allocate their attention to the indicated modality. Experiment 3 utilized a choice reaction paradigm (in which subjects pressed different buttons in response to the onset of the light and the tone) in order to examine their attention allocation when no precues were provided. It was found that the adults and 7-year-olds tended to allocate their attention to vision rather than audition when no precue was provided. The results with the 4-year-olds were not entirely consistent, but suggested a similar biasing of attention to vision on their part as well.     

Examining the time course of facilitation and inhibition with simultaneous onset and offset cues

The experiment conducted examined the effect of simultaneously presented onset and offset cues on the orienting of attention in the visual field. Subjects were presented with a display that consisted of four placeholder boxes around a central fixation point. An onset and an offset cue appeared simultaneously in two of the locations, and the other two locations provided a neutral baseline condition. Reaction times were measured in a simple target detection task with stimulus-onset asynchronies (SOAs) that ranged from 100 ms to 1,000 ms. As expected, the onset cue produced early facilitation and later occurring inhibition of return (IOR). The offset cue produced significant inhibition at all but the earliest SOA. These results suggest that simultaneously presented onset and offset cues both capture attention, but that attention is rapidly disengaged from the location of the offset cue, resulting in earlier occurring IOR. For the onset cues, attention is allocated for a longer period of time, producing the typical pattern of early facilitation and later occurring IOR. The differing time course of attention at each location may reflect separate facilitatory and inhibitory processes, and the priority given to the onset of a stimulus by the attentional system.     

Examining inhibition of return with onset and offset cues in the multiple-cuing paradigm

Three experiments examined inhibition of return (IOR) with onset and offset cues in a multiple-cuing paradigm. In the first two experiments, five sequential cues either appeared and remained present (onset cues) or disappeared and remained absent (offset cues). In the third experiment, the cues were either onset cues or on-off cues (appeared and then disappeared quickly after). With placeholders present, onset and offset cues produced similar declines in IOR from the most recently cued location (Experiment 1). In contrast, onset cues produced overall more IOR than on-off cues (Experiment 3). With placeholders absent (Experiment 2), no IOR was found for either onset or offset cues. The results suggest that even in a complex multiple-cuing paradigm, onsets and offsets are treated similarly by the attentional system. Furthermore, it appears that onset cues are easier to encode as previously searched than on-off cues, suggesting a role of working memory in IOR. Finally, when multiple locations are cued sequentially by onsets and offsets they must be marked by placeholders for inhibition to occur.     

The effects of onsets and offsets on visual attention

 Two experiments are presented which examine the effect of onset and offset cues on early occurring attentional cueing effects and later occurring inhibition of return (IOR). The first experiment compared the effects of single onset cues, single offset cues, and simultaneous onset and offset cues (at opposite locations) at a 100-ms stimulus-onset-asynchrony (SOA) and IOR at a 900-ms SOA. Whereas the first experiment examined these conditions with choice localization keypress responses, the second experiment used simple detection keypress responses. Both experiments found that onset and offset cues presented in isolation produce early facilitation and late IOR. When onset and offset cues were simultaneously presented, facilitation but not IOR was found with localization responses, while neither facilitation or IOR was found with detection responses. Overall, these findings suggest that offset cues can be treated in the same manner as onset cues by the attentional system, although the onset cues may have priority in orienting attention when targets must be localized in space. Received: 26 May 2000 / Accepted: 31 January 2001     

Better late than never: how onsets and offsets influence prior entry and exit

The three experiments presented in the paper examine visual prior entry (determining which of two stimuli appeared first) and prior exit (determining which of two stimuli disappeared first) effects with a temporal order judgment (TOJ) task. In addition to using onset and offset targets, the preceding cues also consisted of either onset or offset stimuli. Typical, and equivalent, prior entry effects were found when either onset or offset cues preceded the onset targets. Unexpectedly large prior exit effects where found with the offset targets, with offset cues producing greater capture effects than onset cues. These findings are consistent with the notion that more attention is allocated to searching the visual field when targets are more difficult to find. In addition, the results indicate that attentional control settings may be more likely to occur with more difficult searches. In addition, these findings demonstrate that TOJ tasks provide extremely precise measures of the allocation of attention and are very sensitive to a range of task manipulations.     

The scaling of spatial attention in visual search and its modification in healthy aging

A model of visual search (Greenwood & Parasuraman, 1999) postulating that visuospatial attention is composed of two processing components--shifting and scaling of a variable-gradient attentional focus--was tested in three experiments. Whereas young participants are able to dynamically constrict or expand the focus of visuospatial attention on the basis of prior information, in healthy aging individuals visuospatial attention becomes a poorly focused beam, unable to be constricted around one array element. In the present work, we sought to examine predictions of this view in healthy young and older participants. An attentional focus constricted in response to an element-sized precue had the strongest facilitatory effect on visual search. However, this was true only when the precue correctly indicated the location of a target fixed in size. When precues incorrectly indicated target location or when target size varied, the optimal spatial scale of attention for search was larger, encompassing a number of array elements. Healthy aging altered the deployment of attentional scaling: The benefit of valid precues on search initially (in participants 65-74 years of age) was increased but later (in those 75-85 years of age) was reduced. The results also provided evidence that cue size effects are attentional, not strategic. This evidence is consistent with the proposed model of attentional scaling in visual search.     

Oculomotor readiness and covert orienting: Differences between central and peripheral precues

The costs produced by invalid precues can depend on the spatial relationship between the cued location and the target location. If oculomotor programs mediate attention shifts, then the effect of varying the spatial relation between the cue and target should be the same for covert orienting (indexed by manual responses) and saccadic responses. We found this to be true only for central precues. With central precues, both manual and saccadic costs were greater when cue and target occurred on opposite sides of the vertical meridian than when they occurred on the same side. With peripheral precues, there were no meridian effects in either response condition, but there was a significant dissociation in the pattern of saccadic and manual costs. For manual responses costs were greater when the target was eccentric relative to the cue, whereas for saccades costs were greater when the cue was eccentric to the target. These results provide additional support for the idea that different orienting mechanisms are engaged by central and peripheral precues. They further suggest that the relationship between oculomotor and attentional orienting may depend on the nature of the precue, with the potential for interdependence being greater with central precues.     

Oculomotor readiness and covert orienting: differences between central and peripheral precues.

The costs produced by invalid precues can depend on the spatial relationship between the cued location and the target location. If oculomotor programs mediate attention shifts, then the effect of varying the spatial relation between the cue and target should be the same for covert orienting (indexed by manual responses) and saccadic responses. We found this to be true only for central precues. With central precues, both manual and saccadic costs were greater when cue and target occurred on opposite sides of the vertical meridian than when they occurred on the same side. With peripheral precues, there were no meridian effects in either response condition, but there was a significant dissociation in the pattern of saccadic and manual costs. For manual responses costs were greater when the target was eccentric relative to the cue, whereas for saccades costs were greater when the cue was eccentric to the target. These results provide additional support for the idea that different orienting mechanisms are engaged by central and peripheral precues. They further suggest that the relationship between oculomotor and attentional orienting may depend on the nature of the precue, with the potential for interdependence being greater with central precues.     

Relationship between working memory capacity and contingent involuntary orienting

Individual differences in working memory capacity are related to the ability to control attention; where less working memory capacity is associated with less attentional control. A well-known demonstration of attentional control is contingent involuntary orienting (Folk, Remington, & Johnston, 1992), which is the finding that visuospatial attention is captured by a salient peripheral cue, but only if the cue is featurally similar to the target of search and not if the cue is featurally dissimilar. This control of attention and ability to resist shifting attention towards an irrelevant visual cue is believed to be moderated by attentional settings for target-specific features. This study establishes that working memory capacity is related to contingent involuntary orienting of attention. Lower working memory capacity was associated with larger stimulus-driven cueing effects at short cue-to-target onset asynchronies, than at longer asynchronies, suggesting working memory capacity was associated with the ability to control covert orienting of attention at early processing stages.     

Inhibition of return and attentional control settings

In the present study, we used a spatial cuing paradigm in conjunction with a choice identification task to investigate whether exogenous attentional orienting and inhibition of return are affected by attentional control settings. As in previous studies (e.g., Folk, Remington, & Johnston, 1992), onset- and color-defined targets were crossed with uninformative onset- and color-defined cues. As expected, when the cue-target stimulus onset asynchrony (SOA) was short (i.e., 100 msec), the results showed that exogenous attentional orienting was contingent on attentional set; attentional capture occurred in response to a particular cue only when the feature that defined the cue also defined the target (Folk et al., 1992). More importantly, when the cue-target SOA was long (i.e., 1,000 msec), the results showed that the occurrence of inhibition of return was also contingent on attentional set, at least partially so; inhibition of return occurred in response to onset cues only when they preceded onset targets. In contrast, inhibition of return never occurred in response to color cues (at a variety of long SOAs). The associations and dissociations that were observed between exogenous attentional orienting and inhibition of return are discussed in terms of posterior and anterior attention networks in the brain (Posner & Petersen, 1990).     

Attentional capture by object appearance and disappearance

In two experiments we examined whether the appearance of a new object has attentional priority over disappearance. Previous failures to show differences are possibly due to onsets and offsets always being presented as a sole visual transient. Rather than presenting each alone, we presented onset and offset singletons simultaneously with a display-wide luminance transient in order to force each to compete with other visual events. Results from Experiment 1 showed that targets associated with onsets accrued a reaction time benefit whilst targets associated with offsets did not. Experiment 2 showed that onsets attracted attention even when observers were attentionally set to look for offset. By contrast, offsets needed a relevant attentional set in order to attract attention. We argue that the appearance of an object has attentional priority over disappearance.     

Perceptual load modulates attentional capture by abrupt onsets

The abrupt appearance of a new object captures attention, even when the object is task irrelevant. These findings suggest that abrupt onsets capture attention in a stimulus-driven manner and are not susceptible to top-down influences on attentional control. However, previous studies examining the ability of abrupt onsets to capture attention have used search displays that lacked significant complexity. Because attention is a limited capacity mechanism, it is possible that increasing the complexity, or perceptual load, of the search arrays may modulate capture by abrupt onsets. We used a flanker task to examine the effect of perceptual load on attentional capture by abruptly appearing objects. Subjects searched for a target letter through low-load (set size=1) and high-load (set size=6) displays. On each trial, irrelevant flankers also appeared, one as an onset and the other as an offset. Onset flankers affected search in low-load but not high-load displays. This modulation of attentional capture was not caused by generalized slowing when subjects searched through high-load displays; search for a single perceptually degraded target slowed response times but did not affect attentional capture. These findings demonstrate that attentional capture by an abrupt onset is attenuated when people search through high-load scenes.     

Visual orienting with central and peripheral precues: Deconfounding the contributions of cue eccentricity,cue discrimination and spatial correspondence

Five experiments examined effects of spatial precues on visual attention. Precues consisted of letters (X, T, O) presented bilaterally at central and peripheral locations.In the spatial correspondence conditions targets tended (p= .8) to appear on the same side as one of the letters. In the spatial translation conditions the bilateral letters were identical; one letter (e.g., X) indicated that the target would probably (p= .8) appear on the left, and the other (e.g., T) indicated that the target would probably appear on the right. In the spatial correspondence conditions (Experiments 1, 3A, 4, and 5) response latencies were quicker on valid than invalid trials, even at very brief (0 ms, 33 ms, 66 ms, 100 ms) stimulus onset asynchronies (SOAs) between cue and target onset. Also,the dynamic pattern of cost and benefit resembled that seen in previous studies with unilateral peripheral precues. In the spatial translation conditions (Experiments 2 and 3B), a clear advantage for valid trials was only apparent at somewhat longer SOAs (150 ms, 300 ms, 500 ms). Results show that the need to discriminate between cue stimuli, and the visual eccentricity of cues, are not critical factors mediating attentional effects of spatial precues. However, the presence or absence of spatial correspondence between the location of a cue stimulus and the location of the target was critically important.     

Investigating the role of exogenous cueing on selection history formation

An abundance of recent empirical data suggest that repeatedly allocating visual attention to task-relevant and/or reward-predicting features in the visual world engenders an attentional bias for these frequently attended stimuli, even when they become task irrelevant and no longer predict reward. In short, attentional selection in the past hinders voluntary control of attention in the present. But do such enduring attentional biases rely on a history of voluntary, goal-directed attentional selection, or can they be generated through involuntary, effortless attentional allocation? An abrupt visual onset triggers such a reflexive allocation of covert spatial attention to its location in the visual field, automatically modulating numerous aspects of visual perception. In this Registered Report, we asked whether a selection history that has been reflexively and involuntarily derived (i.e., through abrupt-onset cueing) also interferes with goal-directed attentional control, even in the complete absence of exogenous cues. To build spatially distinct histories of exogenous selection, we presented abrupt-onset cues twice as often at one of two task locations, and as expected, these cues reflexively modulated visual processing: task accuracy increased, and response times (RTs) decreased, when the cue appeared near the target’s location, relative to that of the distractor. Upon removal of these cues, however, we found no evidence that exogenous selection history modulated task performance: task accuracy and RTs at the previously most-cued and previously least-cued sides were statistically indistinguishable. Thus, unlike voluntarily directed attention, involuntary attentional allocation may not be sufficient to engender historically contingent selection biases.

     

Grabbing attention without knowing: Automatic capture of attention by subliminal spatial cues

The present study shows that an abrupt onset cue that is not consciously perceived can cause attentional facilitation followed by inhibition at the cued location. The observation of this classic biphasic effect of facilitation followed by inhibition of return (IOR) suggests that the subliminal cue captured attention in a purely exogenous way. Since IOR is not observed following endogenous shifts of spatial attention, but is observed following exogenous, stimulus-driven shifts of spatial attention, it is unlikely that top-down control settings or other non-attentional effects played a role. The current findings are interpreted in terms of a neurobiological model of visual awareness.