Early visual tagging: effects of target-distractor similarity and old age on search, subitization, and counting

Three experiments examined the effects of target-distractor (T-D) similarity and old age on the efficiency of searching for single targets and enumerating multiple targets. Experiment 1 showed that increasing T-D similarity selectively reduced the efficiency of enumerating small (< 4) numerosities (subitizing) but had little effect on enumerating larger numerosities (counting) or searching for a single target. Experiment 2 provided converging evidence using fixation frequencies and a finer range of T-D similarities. Experiment 3 showed that T-D similarity had a greater impact on older than on young adults, but only for subitizing. The data are discussed in terms of the mechanisms and architecture of early visual tagging, dissociable effects in search and enumeration, and the effects of aging on visual processing.     

The role of attention in subitizing

The process of rapidly and accurately enumerating small numbers of items without counting, i.e. subitizing, is often believed to rest on parallel preattentive processes. However, the possibility that enumeration of small numbers of items would also require attentional processes has remained an open question. The present study is the first that directly contrasts the preattentive and attentive models of subitizing. We used an inattentional blindness paradigm to manipulate the availability of attentional resources during enumeration. In the inattention condition, the items to be enumerated were presented unexpectedly while participants focused on a line length comparison task. Divided- and full-attention conditions were also included. The results showed that only numbers one and two could be enumerated when the effects of attention were minimized. Freeing attentional resources increased the enumeration accuracies considerably, including for number two. The results suggest that even for enumerating small numbers, the attentional demands increase as the number of objects increases.     

听觉通道下负数的低水平加工引起注意的SNARC效应

采用刺激探测任务,探讨了听觉通道下负数的低水平加工能否引起注意的SNARC效应。结果表明:(1)负数的低水平加工能够产生注意的SNARC效应,即线索为绝对值小的负数时,被试对左耳目标反应更快;线索为绝对值大的负数时,被试对右耳目标反应更快。(2)负数的加工所引起听觉空间注意的转移并不依赖于负数所在的情境,而仅通过其绝对值大小与空间表征发生关联。这一结论与视觉条件下所得到的结论不一致,并支持了系统发生论假说。     

负性情绪对注意促进效应的调节

近期研究发现,目标探测性质的注意分散并不会削弱,甚至会提高与之同时进行的记忆任务成绩,表现出注意促进效应（ABE）,但该效应可能会受到记忆材料独特性的调节。为了验证该假设,本文采用负性刺激为记忆材料,以目标探测任务为干扰任务,探讨负性情绪对ABE的调节。结果发现,与中性材料相比,负性材料的ABE有所减弱;而高唤醒的负性材料则没有表现出任何的ABE。可见目标探测所产生的促进作用会受到背景材料是否具有独特性的限制。     

Effects of prime and target eccentricity on masked repetition priming

Three experiments examined the influence of briefly presented, pattern-masked prime stimuli on target word recognition at varying eccentricities. The prime was either the same word as the targets or a different word, and prime position varied horizontally from a central fixation point. The targets were either in the same location as the primes (Experiment 1A) or always centrally located (Experiments 1B and 2). In Experiment 1A, target word recognition showed a typical right visual field advantage, and priming effects diminished with increasing prime and target eccentricity. With centrally located targets, priming effects tended to be more constrained by prime location. After eye fixation location and prime visibility were controlled for (Experiment 2), a right visual field advantage for priming effects was also evident for central targets, suggesting an influence of endogenous attentional biases in masked repetition priming.     

To look or not to look: an eye movement study of hypervigilance during change detection in high and low spider fearful students

Previous eye movement studies of attentional bias in spider fear reported inconsistent results with respect to early attentional capture, suggesting that overt attentional capture only reliably occurs under specific circumstances. In addition, none of these studies explored covert attention. The present study examined attentional bias in spider phobia using a change detection paradigm that was expected to provide good conditions for documenting attentional capture. In contrast to our expectations, eye movement data showed that all participants' first fixations were fastest on general negative targets, whereas participants' first fixations on spider targets were slower in the spider fearful than in the nonfearful group. In addition, spider fearful participants made more nontarget fixations before fixating on a spider target than did nonfearful participants. Thus, we found that participants' overt attention was more quickly focused on general negative targets, whereas covert attentional processes enabled initial avoidance of fear-relevant (i.e. spider) stimuli. The present findings have important implications for research on attention and fear as they indicate that fearful individuals are not characterized by static attentional orienting toward threat but, under certain conditions, may avert attention from threat automatically.     

An apparent-motion confound causes the negative exogenous cuing effect at SOAs with larger numbers of target locations

Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.     

Components representation of negative numbers: evidence from auditory stimuli detection and number classification tasks

Past research suggested that negative numbers could be represented in terms of their components in the visual modality. The present study examined the processing of negative numbers in the auditory modality and whether it is affected by context. Experiment 1 employed a stimuli detection task where only negative numbers were presented binaurally. Experiment 2 employed the same task, but both positive and negative numbers were mixed as cues. A reverse attentional spatial-numerical association of response codes (SNARC) effect for negative numbers was obtained in these two experiments. Experiment 3 employed a number classification task where only negative numbers were presented binaurally. Experiment 4 employed the same task, but both positive and negative numbers were mixed. A reverse SNARC effect for negative numbers was obtained in these two experiments. These findings suggest that negative numbers in the auditory modality are generated from the set of positive numbers, thus supporting a components representation.     

Attentional bias for negative expressions depends on previous target location: replicable effect but unreliable measures

ABSTRACT

Observability of threat-related spatial attentional biases may require previous-trial responses associated with threat-related locations. This carryover effect might affect reliability and correlations. In Study 1, a diagonalized Visual Probe Task was completed online (N=131) with colour, anger, fear and disgust stimuli, with questionnaires on aggression, anxiety, depression and impulsivity. Bias towards negative stimuli was found only following previous targets on the negative location. Study 2 aimed to test an interpretation in terms of cue-evoked attention. Task variants were completed (N=101) with and without removal of the cue when targets appeared. Anger and disgust stimuli and aggression, anxiety and depression scales were used. Carryover was replicated with no interaction with cue offset. Over both tasks, reliability was low and no robust correlations with questionnaires were found. Carryover thus determined whether attentional bias to negative facial expressions was observed, but analyses taking this into account did not improve reliability or reveal correlations.     

Components representation of negative numbers: Evidence from auditory stimuli detection and number classification tasks

Past research suggested that negative numbers could be represented in terms of their components in the visual modality. The present study examined the processing of negative numbers in the auditory modality and whether it is affected by context. Experiment 1 employed a stimuli detection task where only negative numbers were presented binaurally. Experiment 2 employed the same task, but both positive and negative numbers were mixed as cues. A reverse attentional spatial–numerical association of response codes (SNARC) effect for negative numbers was obtained in these two experiments. Experiment 3 employed a number classification task where only negative numbers were presented binaurally. Experiment 4 employed the same task, but both positive and negative numbers were mixed. A reverse SNARC effect for negative numbers was obtained in these two experiments. These findings suggest that negative numbers in the auditory modality are generated from the set of positive numbers, thus supporting a components representation.     

无关工作记忆表征的负性情绪信息能否捕获视觉注意?一项眼动研究

研究通过分析视觉搜索任务的首次注视点和行为反应时, 探讨无关工作记忆表征的负性情绪信息对视觉注意选择的影响。实验1发现在反映早期注意选择的首次注视点百分率指标上, 不管工作记忆表征的情绪效价如何, 均出现了显著的注意捕获效应; 实验2发现当采用中性情绪靶子刺激时, 首次注视点百分率指标上仍表现出了稳健的注意捕获效应; 在首次注视点持续时间指标上, 实验1和实验2均发现记忆匹配条件的干扰刺激显著小于控制条件的干扰刺激, 表现出注意的快速脱离; 而在行为反应时指标上, 早期的注意捕获效应消失(实验1), 甚至被反转为注意抑制效应(实验2)。这些结果表明在早期注意选择阶段, 记忆驱动的注意捕获效应不受工作记忆表征情绪效价的影响, 但认知控制会在早期注意捕获之后促使注意快速脱离记忆匹配的干扰刺激, 其作用效果受靶子刺激情绪效价的调节。     

Spatial frequency and attention: Effects of level-, target-, and location-repetition on the processing of global and local forms

Is attentional selection between local and global forms based on spatial frequency? This question was examined by having subjects identify local or global forms of stimuli that had been “contrast balanced,” a technique that eliminates low spatial frequencies. Response times (RTs) to global (but not local) forms were slowed for contrast-balanced stimuli, suggesting that low spatial frequencies mediate the global RT advantage typically reported. In contrast, the beneficial effect of having targets appear at the same, as opposed to a different, level as that on the immediately preceding trial was unaffected by contrast balancing. This suggests that attentional selection between different levels of structure is not based on spatial frequency. The data favor an explanation in terms of “priming,” rather than in terms of adjustments in the diameter of an attentional “spotlight.”     

Spatial attention is necessary for object-based attention: Evidence from temporal-order judgments

Attentional selection is a dynamic process that relies on multiple types of representations. That object representations contribute to attentional selection has been known for decades; however, most evidence for this contribution has been gleaned from studies that have relied on various forms of spatial cueing (some endogenous and some exogenous). It has thus remained unclear whether object-based attentional selection is a direct result of spatial cuing, or whether it still emerges without any spatial marker. Here we used a novel method—the temporal-order judgment (TOJ)—to examine whether object-based guidance emerges in the absence of spatial cuing. Participants were presented with two rectangles oriented either horizontally or vertically. Following a 150-ms preview time, two target stimuli were presented on the same or on different objects, and participants were asked to report which of the two stimuli had appeared first. The targets consisted of stimuli that formed a percept of a “hole” or a “hill.” First, we demonstrated that the “hill” target was indeed processed faster, as evidenced by a positive perceived simultaneity (PSS) measure. We then demonstrated that if two targets appeared with equal probabilities on the same and on different objects, the PSS values, although positive, were not modulated by the objects. In a subsequent set of experiments, we showed that objects can modulate attentional allocation—however, only when they are biased by a spatial (endogenous) cue. In other words, in the absence of a spatial cue or bias, object representations do not guide attentional selection. In addition to providing new constraints for theories of object-based attentional guidance, these experiments introduce a novel paradigm for measuring object-based attentional effects.     

Task switching mediates the attentional blink even without backward masking

When two targets are presented in rapid succession, perception of the second target is impaired at short intertarget lags (100-700 msec). This attentional blink (AB) is thought to occur only when the second target is backward masked. To the contrary, we show that task switching between the targets can produce an AB even without masking (Experiments 1 and 3). Further, we show that task switching produces an AB only when the second target does not belong to a class of overlearned stimuli such as letters or digits (Experiments 1 and 4). When the second target is masked, however, an AB is invariably obtained regardless of switching or overlearning. We propose that task switching involves a time-consuming process of reconfiguration of the visual system, during which the representation of the second target decays beyond recognition, resulting in an AB deficit. We suggest that overlearned stimuli are encoded in a form that, while maskable, decays relatively slowly, thus outlasting the delay due to reconfiguration and avoiding the AB deficit.     

Inhibitory tagging in an interrupted visual search

Inhibition of return facilitates visual search, biasing attention away from previously examined locations. Prior research has shown that, as a result of inhibitory tags associated with rejected distractor items, observers are slower to detect small probes presented at these tagged locations than they are to detect probes presented at locations that were unoccupied during visual search, but only when the search stimuli remain visible during the probe-detection task. Using an interrupted visual search task, in which search displays alternated with blank displays, we found that inhibitory tagging occurred in the absence of the search array when probes were presented during these blank displays. Furthermore, by manipulating participants’ attentional set, we showed that these inhibitory tags were associated only with items that the participants actively searched. Finally, by probing before the search was completed, we also showed that, early in search, processing at distractor locations was actually facilitated, and only as the search progressed did evidence for inhibitory tagging arise at those locations. These results suggest that the context of a visual search determines the presence or absence of inhibitory tagging, as well as demonstrating for the first time the temporal dynamics of location prioritization while search is ongoing.     

Searching for two things at once: Establishment of multiple attentional control settings on a trial-by-trial basis

Recent work has demonstrated that attention can be configured to multiple potential targets in spatial search. However, this previous work relied on a fixed set of targets across multiple trials, allowing observers to offload attentional control settings to longer-term representations. In the present experiments, we demonstrate multiple attentional control settings that operate independently of space (Experiments 1 and 2). More important, we show that observers can be cued to different control settings on a trial-by-trial basis (Experiment 3). The latter result suggests that observers were capable of maintaining multiple control settings when the demands of the task required an attentional search for specific feature values. Attention can be configured to extract multiple feature values in a goal-directed manner, and this configuration can be can be dynamically engaged on a trial-by-trial basis. These results support recent findings that reveal the high precision, complexity, and flexibility of attentional control settings.     

Categorization processes in mental comparisons

Five experiments explore categorization and category-based congruity effects in mental comparisons. The first 4 experiments concentrate on categorization of infinite-set small items. The experiments vary the additional items presented and whether those items appear once (Experiments 1-2) or repeatedly (Experiments 3-4). Additional items include other small items (Experiment 1), relatively large items (Experiments 2-4), and items involving nonsize dimensions (Experiment 4). The critical small items show a complete congruity effect only in Experiments 1 and 3. Results suggest that categorization of infinite-set items may be based on range information alone (Experiment 1) but that multiple categorizations based on multiple ranges (Experiment 2) may require attentional effort. Results implicate categorization as a central process in mental comparison, despite differences in ease of categorization across paradigm.     

Boundary conditions for the influence of unfamiliar non-target primes in unconscious evaluative priming: The moderating role of attentional task sets

Evaluative priming by masked emotional stimuli that are not consciously perceived has been taken as evidence that affective stimulus evaluation can also occur unconsciously. However, as masked priming effects were small and frequently observed only for familiar primes that there also presented as visible targets in an evaluative decision task, priming was thought to reflect primarily response activation based on acquired S–R associations and not evaluative semantic stimulus analysis. The present study therefore assessed across three experiments boundary conditions for the emergence of masked evaluative priming effects with unfamiliar primes in an evaluative decision task and investigated the role of the frequency of target repetition on priming with pictorial and verbal stimuli. While familiar primes elicited robust priming effects in all conditions, priming effects by unfamiliar primes were reliably obtained for low repetition (pictures) or unrepeated targets (words), but not for targets repeated at a high frequency. This suggests that unfamiliar masked stimuli only elicit evaluative priming effects when the task set associated with the visible target involves evaluative semantic analysis and is not based on S–R triggered responding as for high repetition targets. The present results therefore converge with the growing body of evidence demonstrating attentional control influences on unconscious processing.     

Facilitation and interference of behavioral responses by task-irrelevant affect-laden stimuli

Emotional interference on behavior is commonly observed when task-irrelevant negative stimuli appear before behavioral targets. One explanation postulates that affect-laden stimuli readily capture attention, interfering with the processing of the upcoming target. Emotional stimuli might also preactivate motor programs incompatible with the demanded response. Using a cued go/no-go procedure we showed that task-irrelevant unpleasant stimuli cause interference or facilitation depending on their onset asynchrony relative to the target. We observed interference with short (200 ms) stimulus-target asynchronies and facilitation for longer ones (600 ms), both for key press (Experiment 1) and key release (Experiment 2) responses. The interference effect is compatible with an attentional explanation, but the behavioral facilitation is hard to accommodate within either attentional or motor accounts. This interference-facilitation pattern can be explained assuming that once the attentional effect subsides, emotional processing may enhance the perceptual processing of the stimuli, or lower the decision threshold, thereby facilitating the response selection process.     

The naked truth: Positive,arousing distractors impair rapid target perception

Emotional stimuli tend to capture and hold attention more than non-emotional stimuli do. Aversive pictures have been found to impair perception of visual targets even after the emotional information has disappeared. The benefits of such interlinked emotion and attention systems have sometimes been discussed within an evolutionary framework, with a survival advantage attributed to early detection of threatening stimuli. However, consistent with recent suggestions that attention is drawn to arousing stimuli regardless of whether they are positive or negative, the current investigation found that erotic distractors—generally rated as both pleasing and arousing—consistently elicited a transient “emotion-induced blindness” similar to that caused by aversive distractors (Experiment 1). This effect persisted despite performance-based monetary incentives to ignore the distractors (Experiment 2), and following attentional manipulations that reduced interference from aversive images (Experiment 3). The findings indicate that positively arousing stimuli can spontaneously cause emotion-induced deficits in visual processing, just as aversive stimuli can.