Does conspicuity enhance distraction? Saliency and eye landing position when searching for objects

While visual saliency may sometimes capture attention, the guidance of eye movements in search is often dominated by knowledge of the target. How is the search for an object influenced by the saliency of an adjacent distractor? Participants searched for a target amongst an array of objects, with distractor saliency having an effect on response time and on the speed at which targets were found. Saliency did not predict the order in which objects in target-absent trials were fixated. The within-target landing position was distributed around a modal position close to the centre of the object. Saliency did not affect this position, the latency of the initial saccade, or the likelihood of the distractor being fixated, suggesting that saliency affects the allocation of covert attention and not just eye movements.     

Attentional capture of objects referred to by spoken language

Participants saw a small number of objects in a visual display and performed a visual detection or visual-discrimination task in the context of task-irrelevant spoken distractors. In each experiment, a visual cue was presented 400 ms after the onset of a spoken word. In experiments 1 and 2, the cue was an isoluminant color change and participants generated an eye movement to the target object. In experiment 1, responses were slower when the spoken word referred to the distractor object than when it referred to the target object. In experiment 2, responses were slower when the spoken word referred to a distractor object than when it referred to an object not in the display. In experiment 3, the cue was a small shift in location of the target object and participants indicated the direction of the shift. Responses were slowest when the word referred to the distractor object, faster when the word did not have a referent, and fastest when the word referred to the target object. Taken together, the results demonstrate that referents of spoken words capture attention.     

Object-based visual attention with endogenous orienting

In a series of experiments, we examined covert orienting using endogenous cuing, in which attention is voluntarily directed toward a peripheral location. In one experiment, subjects were cued to attend to one end of an oblong object. They then detected targets on the cued object or elsewhere. In another experiment, subjects provided judgments of the relative temporal order of two flashes after their attention had moved endogenously. In a third experiment, subjects were directed to attend to an empty spatial location and subsequently discriminated features of objects that appeared at or near the locus of attention. In each of these situations, attentional orienting was object based, in the sense that nonattended locations that were on the cued object had an advantage over nonattended locations that were not on the object. The results are discussed in terms of their implications for object-based representations and the differences between exogenous and endogenous orienting of attention.     

When does visual attention select all features of a distractor?

What happens after visual attention is allocated to an object? Although many theories of attention assume that all of its features are selected and processed, there has been little direct evidence that an irrelevant feature dimension of an attended nontarget is processed. In 5 experiments presented here, the authors used a singleton paradigm to investigate the effect of attention on nontarget objects. Participants made a speeded feature discrimination of a target for which the response was either compatible or incompatible with an irrelevant feature dimension of a distractor. The results show that the irrelevant distractor features were processed to the point that they interfered with the response to the target. The response compatibility effect was observed even when the location of the target or the distractor was invariant, although it was much weaker when both locations were invariant. These results demonstrate that in many circumstances, an attended distractor is completely selected and fully processed, and the complete processing of distractors depends on a number of factors, many of which are related to the strength of attention to the distractor.     

Covert visual attention and extrafoveal information use during object identification

Three experiments are reported that examined the relationship between covert visual attention and a viewer's ability to use extrafoveal visual information during object identification. Subjects looked at arrays of four objects while their eye movements were recorded. Their task was to identify the objects in the array for an immediate probe memory test. During viewing, the number and location of objects visible during given fixations were manipulated. In Experiments 1 and 2, we found that multiple extrafoveal previews of an object did not afford any more benefit than a single extrafoveal preview, as assessed by means of time of fixation on the objects. In Experiment 3, we found evidence for a model in which extrafoveal information acquired during a fixation derives primarily from the location toward which the eyes will move next. The results are discussed in terms of their implications for the relationship between covert visual attention and extrafoveal information use, and a sequential attention model is proposed.     

Time course of visual attention with emotional faces

When a briefly presented and then masked visual object is identified, it impairs the identification of the second target for several hundred milliseconds. This phenomenon is known as attentional blink or attentional dwell time. The present study is an attempt to investigate the role of salient emotional information in shifts of covert visual attention over time. Two experiments were conducted using the dwell time paradigm, in which two successive targets are presented at different locations with a variable stimulus onset asynchrony (SOA). In the first experiment, real emotional faces (happy/sad) were presented as the first target, and letters (L/T) were presented as the second target. The order of stimulus presentation was reversed in the second experiment. In the first experiment, identification of the letters preceded by happy faces showed better performance than did those preceded by sad faces at SOAs less than 200 msec. Similarly, happy faces were identified better than sad faces were at short SOAs in Experiment 2. The results show that the time course of visual attention is dependent on emotional content of the stimuli. The findings indicate that happy faces are associated with distributed attention or broad scope of attention and require fewer attentional resources than do sad faces.     

Attentional selection during preparation of prehension movements

In two experiments coupling between dorsal attentional selection for action and ventral attentional selection for perception during preparation of prehension movements was examined. In a dual-task paradigm subjects had to grasp an X-shaped object with either the left or the right hand's thumb and index finger. Simultaneously a discrimination task was used to measure visual attention prior to the execution of the prehension movements: Mask items transiently changed into distractors or discrimination targets. There was exactly one discrimination target per trial, which appeared at one of the four branch ends of the object. In Experiment 1 target position varied randomly while in Experiment 2 it was constant and known to subjects in each block of trials. In both experiments discrimination performance was significantly better for discrimination target positions at to-be-grasped branch ends than for not-to-be-grasped branch ends. We conclude that during preparation of prehension movements visual attention is largely confined to those parts of an object that will be grasped.     

Effects of a moving distractor object on time-to-contact judgments

The effects of moving task-irrelevant objects on time-to-contact (TTC) judgments were examined in 5 experiments. Observers viewed a directly approaching target in the presence of a distractor object moving in parallel with the target. In Experiments 1 to 4, observers decided whether the target would have collided with them earlier or later than a standard (absolute identification task). A contrast effect was observed: If the distractor arrived later than the target, it caused a bias toward early responses, relative to the condition without a distractor. The early-arriving distractor had no significant effect. The pattern of results was unaltered when potentially confounding information from individual visual cues was removed. The availability of stereoscopic information reduced the effect. The contrast effect was also observed if target and distractor were abstract geometric objects rather than simulations of real-world vehicles, rendering less likely a simple safety strategy activated by a potentially threatening distractor. Experiment 5 showed that the effect of the late-arriving distractor generalized to a prediction-motion task. The results indicate that task-irrelevant information in the background has to be considered in revision of time-to-contact theory.     

Object files across eye movements: Previous fixations affect the latencies of corrective saccades

One of the factors contributing to a seamless visual experience is object correspondence—that is, the integration of pre- and postsaccadic visual object information into one representation. Previous research had suggested that before the execution of a saccade, a target object is loaded into visual working memory and subsequently is used to locate the target object after the saccade. Until now, studies on object correspondence have not taken previous fixations into account. In the present study, we investigated the influence of previously fixated information on object correspondence. To this end, we adapted a gaze correction paradigm in which a saccade was executed toward either a previously fixated or a novel target. During the saccade, the stimuli were displaced such that the participant’s gaze landed between the target stimulus and a distractor. Participants then executed a corrective saccade to the target. The results indicated that these corrective saccades had lower latencies toward previously fixated than toward nonfixated targets, indicating object-specific facilitation. In two follow-up experiments, we showed that presaccadic spatial and object (surface feature) information can contribute separately to the execution of a corrective saccade, as well as in conjunction. Whereas the execution of a corrective saccade to a previously fixated target object at a previously fixated location is slowed down (i.e., inhibition of return), corrective saccades toward either a previously fixated target object or a previously fixated location are facilitated. We concluded that corrective saccades are executed on the basis of object files rather than of unintegrated feature information.     

Action matters: The role of action plans and object affordances in selection for action

In a series of three experiments requiring selection of real objects for action, we investigated whether characteristics of the planned action and/or the “affordances” of target and distractor objects affected interference caused by distractors. In all ofthe experiments, the target object was selectedon the basis of colour and was presented alone or with a distractor object. We examined the effect of type of response (button press, grasping, or pointing), object affordances (compatibility with the acting hand, affordances for grasping or pointing), and target/distractor positions (left or right) on distractor interference (reaction time differences between trials with and without distractors). Different patterns of distractor interference were associated with different motor responses. In the button-press conditions of each experiment, distractor interference was largely determined by perceptual salience (e.g., proximity to initial visual fixation). In contrast, in tasks requiring action upon the objects in the array, distractors with handles caused greater interference than those without handles, irrespective of whether the intended action was pointing or grasping. Additionally, handled distractors were relatively more salient when their affordances for grasping were strong (handle direction compatible with the acting hand) than when affordances were weak. These data suggest that attentional highlighting of specific target and distractor features is a function of intended actions.     

Oculocentric coding of inhibited eye movements to recently attended locations

Results are reported for experiments that examined eye movements directed toward recently cued objects. In 1 experiment participants were slower to initiate saccades toward the earlier location of an object that had been cued, even though the cued object had subsequently moved away from that location. Other experiments involved exploring the reference frame within which the inhibited eye movements are encoded. These experiments revealed that the eye movement that is inhibited is encoded in an oculocentric-rather than an environmental-reference frame. However, simple detection as indexed by manual keypress responses is encoded in an environmental reference frame. The results have implications for inhibition of return, for the link between eye movements and attention, and for the nature of the spatial reference frames in which both covert and overt movements of attention are encoded.     

Attentional capture with various distractor and target types

Effects of nonpredictive distractors that involved changes in luminance, size, or shape were examined in three experiments. In Experiment 1, with two types of distractors (onsets and offsets), accuracy was better on trials when the distractor was near the location of either an offset or an onset target than on trials when the distractor was in a different location from that of the target, demonstrating attentional capture. Capture occurred both when the type of target (onset or offset) was blocked and therefore predictable and also when the type of target was mixed within blocks and therefore not predictable. Further experiments indicated that distractors captured attention even when the change to distractor did not create a new perceptual object. Neither a singleton-detection mode, nor a contingent involuntary orienting hypothesis, nor creation of a new object seems to explain all of these data adequately. Rather, capture may depend on a number of factors in the task.     

Attentional capture with various distractor and target types

Effects of nonpredictive distractors that involved changes in luminance, size, or shape were examined in three experiments. In Experiment 1, with two types of distractors (onsets and offsets), accuracy was better on trials when the distractor was near the location of either an offset or an onset target than on trials when the distractor was in a different location from that of the target, demonstrating attentional capture. Capture occurred both when the type of target (onset or offset) was blocked and therefore predictable and also when the type of target was mixed within blocks and therefore not predictable. Further experiments indicated that distractors captured attention even when the change to distractor did not create a new perceptual object. Neither a singleton-detection mode, nor a contingent involuntary orienting hypothesis, nor creation of a new object seems to explain all of these data adequately. Rather, capture may depend on a number of factors in the task.     

无关长时记忆表征能否引导视觉注意选择?

与任务相关的长时记忆表征在引导视觉注意选择的过程中扮演着重要的角色,它可以使人们在熟悉的视觉情境中快速搜索目标刺激,并偏离干扰刺激。但当长时记忆表征与任务无关时,还能否引导视觉注意选择?目前还不清楚。实验1采用眼动追踪技术直接比较无关工作记忆表征与无关长时记忆表征在视觉搜索阶段对视觉注意的捕获效应,行为反应时与首次注视点百分率的结果都发现,当无关工作记忆表征在视觉搜索中再次出现时能引导视觉注意偏向到与之匹配的干扰刺激,但无关长时记忆表征并没有表现出类似的注意引导效应;实验2探讨记忆表征由工作记忆系统转移到长时记忆系统的过程中对视觉注意的引导效应,结果发现,随着记忆表征的转移,注意引导效应消失了,实验3排除工作记忆表征的干扰后,依然没有发现无关长时记忆表征对注意的引导效应。以上结果表明,无关长时记忆表征并不能像工作记忆表征一样引导视觉注意选择,工作记忆表征和长时记忆表征对视觉注意的引导属于两个不同的认知过程。     

工作记忆表征捕获眼动中的颜色优先性

刺激属性所具有的引导效力在工作记忆表征自上而下地引导注意捕获过程中起重要作用, 已有研究表明工作记忆表征的颜色属性在引导注意时具有一定的优势。研究采用工作记忆任务与视觉搜索任务相结合的双任务范式, 结合眼动追踪技术, 通过设置具有较强引导效力的颜色属性与朝向属性进行直接竞争的实验条件, 进一步考察工作记忆表征的颜色属性是否依然具有优先性。实验1发现工作记忆表征的颜色属性与朝向属性同时竞争眼动捕获时, 颜色属性表现出较强的优势, 而朝向属性单独呈现时并未表现出任何捕获效应。实验2与3进一步证实了颜色属性捕获眼动的优先性, 即当颜色属性在面临作为靶子属性的朝向属性的竞争时, 依然能捕获更多的注视点。这些结果直接证实了工作记忆表征的颜色属性在工作记忆表征的捕获眼动的过程中具有较强的引导效力, 相对于其他刺激属性(如朝向、形状)更具有优先性。     

Developmental Differences in the Influence of Distractors on Maintenance in Spatial Working Memory

This study examined whether attention to a location plays a role in the maintenance of locations in spatial working memory in young children as it does in adults. This study was the first to investigate whether distractors presented during the delay of a spatial working-memory task influenced young children’s memory responses. Across 2 experiments, 3- and 6-year-olds completed a spatial working-memory task featuring a static target location and distractor location. Results indicated a change from 3 years to 6 years of age in how distractors influenced memory. Six-year-olds’ memory responses were biased away from a distractor that was close to the target location and on the outside of the target location relative to the center of the monitor. Distractors that were far from the target or that were toward the center of the monitor relative to the target location had no effect. Three-year-olds’ responses were biased toward a distractor when the distractor was on the outside of the target location and farther from the target. Distractors that were near the target location or toward the center of the monitor had no effect. These biases provide evidence that young children’s maintenance of a location in memory is influenced by attention.     

预期对注意的影响受制于被预期主体是目标还是分心物

以往研究表明, 预期机制和注意机制都能促进感知行为, 但两者以何种方式共同作用于感知行为仍然存在争议, 特别是, 对于预期主体在其中的作用尚不清楚。本研究采用空间提示以及视觉搜索相结合的范式, 通过4个实验, 考察了当被试对目标进行预期以及对分心物进行预期时, 空间预期对空间注意效应的不同影响。结果显示：(1)当目标为预期主体时, 预期对注意效应具有调节作用; (2)当分心物为预期主体时, 预期与注意的作用独立; (3)当目标为预期主体时, 通过刺激数增加而导致的任务难度变化不影响预期和注意之间的关系。这表明, 空间预期是否影响空间注意效应受制于预期主体——当预期主体为目标时, 预期和注意两者交互式地影响感知行为; 当预期主体为分心物时, 预期和注意独立地影响感知行为; 而且, 预期和注意之间的关系不受任务难度影响。     

Presaccadic target competition attenuates distraction

Although it is well known that salient nontargets can capture attention despite being task irrelevant, several studies have reported short fixation dwell times, suggesting the presence of an attentional mechanism to “rapidly reject” dissimilar distractors. Rapid rejection has been hypothesized to depend on the strong mismatch between distractor features and the target template, but it is unknown whether the presence of strong feature mismatch is sufficient, or if the presence of a target at a competing location is also necessary. Here, we investigated this question by first replicating the finding of rapid rejection for dissimilar distractors in the presence of a concurrent target (Experiment 1); manipulating the onset of the target stimulus relative to the distractor (Experiment 2); and using a saccade-contingent display to delay the target onset until after the first saccade was initiated. The results demonstrate that the speed of distractor rejection depends on the presence of target competition prior to the initiation of the first saccade, and not after the saccade. This suggests that stimulus competition for covert attention sets a “saccade priority map” that unfolds over time, resulting in faster corrective saccades to an anticipated object with higher top-down attentional priority.     

Oculomotor consequences of abrupt object onsets and offsets: onsets dominate oculomotor capture

Previous research has shown that the appearance of an object (onset) and the disappearance of an object (offset) have the ability to influence the allocation of covert attention. To determine whether both onsets and offsets have the ability to influence eye movements, a series of experiments was conducted in which participants had to make goal-directed eye movements to a color singleton target in the presence of an irrelevant onset/offset. In accord with previous research, onsets had the ability to capture the eyes. The offset of an object demonstrated little or no ability to interrupt goal-directed eye movements to the target. Two experiments in which the effects of onsets and offsets on covert attention were examined suggest that offsets do not capture the eyes, because they have a lesser ability to capture covert attention than do onsets. A number of other studies that have shown strong effects of offsets on attention have used offsets that were uncorrelated with target position (i.e., nonpredictive), whereas we used onsets and offsets that never served as targets (i.e., antipredictive). The present results are consistent with a new-object theory of attentional capture in which onsets receive attentional priority over other types of changes in the visual environment.