Object-based attentional selection can modulate the Stroop effect

The Stroop (1935) effect is the inability to ignore a color word when the task is to report the ink color of that word (i.e., to say "green" to the word RED in green ink). The present study investigated whether object-based processing contributes to the Stroop effect. According to this view, observers are unable to ignore irrelevant features of an attended object (Kahneman & Henik, 1981). In three experiments, participants had to name the color of one of two superimposed rectangles and to ignore words that appeared in the relevant object, in the irrelevant object, or in the background. The words were congruent, neutral, or incongruent with respect to the correct color response. Words in the irrelevant object and in the background produced significant Stroop effects, consistent with earlier findings. Importantly, however, words in the relevant object produced larger Stroop effects than did the other conditions, suggesting amplified processing of all the features of an attended object. Thus, object-based processing can modulate the Stroop effect.     

A case for inhibition: visual attention suppresses the processing of irrelevant objects

The present study investigated the ability to inhibit the processing of an irrelevant visual object while processing a relevant one. Participants were presented with 2 overlapping shapes (e.g., circle and square) in different colors. The task was to name the color of the relevant object designated by shape. Congruent or incongruent color words appeared in the relevant object, in the irrelevant object, or in the background. Stroop effects indicated how strong the respective area of the display was processed. The results of 4 experiments showed that words in the relevant object produced larger Stroop effects than words in the background, indicating amplification of relevant objects. In addition, words in the irrelevant object consistently produced smaller Stroop effects than words in the background, indicating inhibition of irrelevant objects. Control experiments replicated these findings with brief display durations (250 ms) and ruled out perceptual factors as a possible explanation. In summary, results support the notion of an inhibitory mechanism of object-based attention, which can be applied in addition to the amplification of relevant objects.     

A Stroop effect for spatial orientation

The author investigated the conditions under which a congruent or incongruent orientation word affects processing of the orientation of visual objects. Participants named the orientation of a rectangle that partially occluded another rectangle. Congruent or incongruent orientation words appeared in the relevant object, in the irrelevant object, or in the background. There were two main results. First, congruent orientation words produced faster orientation-naming responses than incongruent orientation words. This finding constituted a new Stroop effect for spatial orientation. Second, only words in the relevant (i.e., attended) object produced Stroop effects, whereas words outside the relevant object had no significant effects. This object-dependent modulation of Stroop effects resembled previous findings with color-naming tasks, and hence indicated that these modulations are not restricted to a particular type of task. In summary, results suggested that object-based attention plays an important role in processing of irrelevant words.     

Don't be afraid of irrelevant words: the emotional Stroop effect is confined to attended words

The emotional Stroop effect denotes slower responses to the colour of negative words (e.g., death) compared to neutral words (e.g., mug). Popular explanations assume a general power of negative words to capture visual attention. However, in the typical task, the irrelevant word stimulus and the relevant colour stimulus are perceptually integrated. We compared interference from negative words, which were part of the relevant visual object, to interference from negative words that were part of an irrelevant object, or occurred in the background, respectively. Results showed that only negative words in the relevant object delayed colour-naming responses, compared to neutral words. Negative words outside the relevant object failed to affect performance. This finding is at odds with the claim that negative words could capture spatial or object-based mechanisms of visual attention. However, the finding is consistent with the idea that negative words interfere with the allocation of dimensional attention to different features of an attended object.     

Don't be afraid of irrelevant words: The emotional Stroop effect is confined to attended words

The emotional Stroop effect denotes slower responses to the colour of negative words (e.g., death) compared to neutral words (e.g., mug). Popular explanations assume a general power of negative words to capture visual attention. However, in the typical task, the irrelevant word stimulus and the relevant colour stimulus are perceptually integrated. We compared interference from negative words, which were part of the relevant visual object, to interference from negative words that were part of an irrelevant object, or occurred in the background, respectively. Results showed that only negative words in the relevant object delayed colour-naming responses, compared to neutral words. Negative words outside the relevant object failed to affect performance. This finding is at odds with the claim that negative words could capture spatial or object-based mechanisms of visual attention. However, the finding is consistent with the idea that negative words interfere with the allocation of dimensional attention to different features of an attended object.     

The modulation of spatial congruency by object-based attention: analysing the "locus" of the modulation

Earlier studies have demonstrated that spatial cueing differentially reduces stimulus-stimulus congruency (e.g., spatial Stroop) interference but not stimulus-response congruency (e.g., Simon; e.g., Lupiá?ez & Funes, 2005). This spatial cueing modulation over spatial Stroop seems to be entirely attributable to object-based attention (e.g., Luo, Lupiá?ez, Funes, & Fu, 2010). In the present study, two experiments were conducted to further explore whether the cueing modulation of spatial Stroop is object based and/or space based and to analyse the "locus" of this modulation. In Experiment 1, we found that the cueing modulation over spatial Stroop is entirely object based, independent of stimulus-response congruency. In Experiment 2, we observed that the modulation of object-based attention over the spatial Stroop only occurred at a short cue-target interval (i.e., stimulus onset asynchrony; SOA), whereas the stimulus-response congruency effect was not modulated either by object-based or by location-based attentional cueing. The overall pattern of results suggests that the spatial cueing modulation over spatial Stroop arises from object-based attention and occurs at the perceptual stage of processing.     

动态范式中基于客体的返回抑制 ——是客体抑制还是空间抑制的动态更新？

对动态范式中基于客体的返回抑制进行了考察。实验1在双侧客体改变和不改变条件下考察了返回抑制效应,结果表明,在双侧客体改变条件下返回抑制仍然存在。实验2采用单侧客体变化技术对动态范式中基于客体的返回抑制进行了测量,结果发现,在有效线索化条件下,单侧客体改变和不改变条件下对靶子的反应时没有显著差异（p > 0.90）。这些结果表明动态范式中基于客体的返回抑制的机制是空间抑制的动态更新,而不是客体表征受到抑制     

Object-based inhibition of return in static displays

After attention has been oriented to a location, inhibition mechanisms prevent the return of attention shortly afterward. This inhibition can be associated with an object in such a way that after cuing attention to the object, inhibition can move with the object to a new location. Recent research has noted that the object-based inhibition of return effect in moving displays is much smaller than the effect observed in static displays, and hence may be of little functional utility. However, we demonstrate that, on the contrary, the large effects observed in static displays are produced precisely because of the existence of object-based frames, which can be additive with location-based frames of reference.     

Inhibition is picky: Shape difference is a necessary condition for attentional inhibition of irrelevant objects

The present study investigated the conditions for attentional amplification in the processing of relevant objects and for attentional inhibition in the processing of irrelevant objects. Participants reported the color of one of two superimposed objects that was specified by occlusion. Irrelevant color words were presented as part of the relevant object, as part of the irrelevant object, or in the background; the words were either congruent or incongruent with the color of the relevant object. The size of the congruency effects provided a measure of the (relative) strength of the processing of the objects and the background. Finally, the two objects had the same shape in one session and different shapes in another session. In both sessions, results showed larger Stroop effects from words belonging to the relevant object than from words in the background, indicating attentional amplification of the relevant object that was unaffected by object similarity. In contrast, smaller Stroop effects from words belonging to the irrelevant object than from words in the background occurred only when the two objects differed in shape. The latter result suggests that a shape difference is both a necessary and a sufficient condition for inhibiting the processing of an irrelevant visual object.     

Modulation of spatial Stroop by object-based attention but not by space-based attention

Earlier studies have shown that the spatial Stroop effect systematically decreases when a peripheral precue is presented at the same location as the target, compared to an uncued location condition. In this study, two experiments were conducted to explore whether the cueing modulation of spatial Stroop is object based and/or space based. In Experiment 1, we found evidence favouring the view that the cueing modulation of the spatial Stroop effect is entirely object based, as no differences were found in conflict reduction for the same-location and same-object conditions. In Experiment 2, the cue was predictive, and a similar object-based modulation of spatial Stroop was still observed. However, the direction of such modulation was affected by the rectangles' orientation. Overall, the pattern of results obtained favours the object-integration (Lupiáñez & Milliken, 1999; Lupiáñez, Milliken, Solano, Weaver, & Tipper, 2001) and referential-coding accounts (Danziger, Kingstone, & Ward, 2001) and seems to provide evidence against the attention-shift account (Rubichi, Nicoletti, Iani, & Umilta, 1997; Stoffer, 1991).     

基于客体的一致性效应的产生机制

采用具有不同深度信息的剪影和图片刺激为材料,要求被试完成形状判断任务,探究基于客体的一致性效应的产生机制。实验1中客体刺激呈现于屏幕中央位置;实验2进一步增强了刺激空间呈现的左右位置倾向;实验3则通过交叉手的范式分离了反应位置和反应手不同的编码对一致性效应的作用。结果发现:当刺激不存在显著的左右位置信息时,剪影刺激出现了一致性效应,图片则没有;而当刺激的空间位置信息显著时,剪影和图片均出现了一致性效应,这一效应在反应位置和反应手编码分离后仍然存在。因此得出结论:空间位置编码假说对解释基于客体的一致性效应的产生有重要作用。     

On the immunity of perceptual implicit memory to manipulations of attention

In four experiments, we examined the effect of manipulating study phase attention in a Stroop task on the extent of repetition priming in the lexical decision task (LDT). Experiment 1 replicated the immunity of the LDT to division of attention reported by Szymanski and MacLeod (1996), using a standard Stroop configuration. Response times to previously encountered words were identical regardless of whether the participants were required to read the words or name the color in which they were presented. Experiment 2 demonstrated that implementing the Stroop manipulation across separate visual objects reduced but did not eliminate priming of unattended words, provided the words remained in the attended region of the stimulus display. When this constraint was removed in Experiment 3, priming of unattended words disappeared. Experiment 4 demonstrated statistically equivalent priming for attended and unattended words when the Stroop manipulation remained in the same visual object but attention was directed to a single letter of the word. In all four experiments, the Stroop manipulation had a clear effect on recognition. These results qualify claims that the LDT might be immune to manipulations of study phase attention and suggest that the LDT has a lower threshold level of attention at encoding than do other standard implicit tests of memory.     

Asymmetry of congruency effects in spatial Stroop tasks can be eliminated

Three experiments examined whether asymmetry in interference can be eliminated in spatial Stroop tasks. In Experiment 1, responding to arrows or location words written in Chinese and to their locations created spatial Stroop effects of similar sizes. In Experiment 2, responding to a location word embedded in an outline drawing of arrow did not yield a spatial Stroop effect, but responding to the arrow's direction did yield an effect. In Experiment 3, responding to a location word flanked by an arrow and to the arrow rather than the word produced similar sizes of spatial Stroop effects. These results show that asymmetry in spatial Stroop interference can be eliminated in some situations. Although aspects of the results are consistent with predictions of translation and dimensional overlap models, they are in closest agreement overall with an account in terms of the relative strengths of the relevant and irrelevant stimulus–response associations.     

Attentional focus, processing load, and Stroop interference

Although the effects of attentional focus and perceptual load on selective attention when targets and distractors are distinct objects that occupy separate locations are well known, there has been little examination of their role when both relevant and irrelevant information pertains to the same object. In four experiments, participants were shown Stroop color words or strings of letters in a task of speeded color identification. When the participants' attentional focus was manipulated via cue validity or precue size, greater Stroop interference was observed when the attentional focus was narrow than when it was broad. However, when the participants were induced to adopt a comparable attentional focus in a dual-task paradigm, the differential Stroop interference was eliminated. Furthermore, contrary to the prediction of the perceptual load hypothesis, different levels of processing load did not lead to differential Stroop interference. These results emphasize the importance of stimulus structure in understanding distractor processing. They indicate that when relevant and irrelevant information pertains to the same object, narrowing attentional focus increases distractor processing, and perceptual load has a negligible effect on the extent of distractor processing.     

Interference effects in an auditory Stroop task: congruence and correspondence

Two auditory Stroop experiments are reported in which subjects responded vocally to the gender of the speaker of stimulus words. The interference effects found were broadly similar to those of a manual-response auditory Stroop paradigm although response-set effects appeared to operate in the data. In all experimental conditions responses were slower to stimulus words which named potential responses than to those words which did not. Such effects have not been found in previous manual-response experiments and it is suggested that the relatively high degree of S-R and of ideomotor compatibility in the vocal response task, compared with the manual task, may be responsible for this difference between the paradigms.The second experiment enabled a comparison to be made between the effects of congruence between relevant and irrelevant elements of the Stroop stimulus and the effects of correspondence between the response and the irrelevant aspect of the stimulus. A predominant influence of congruence was found when the subject responded using words semantically related to speaker gender, but an effect of correspondence was obtained when an arbitrary pairing of response word and speaker gender was required.     

Time-compressed spoken word primes crossmodally enhance processing of semantically congruent visual targets

Findings from three experiments support the conclusion that auditory primes facilitate the processing of related targets. In Experiments 1 and 2, we employed a crossmodal Stroop color identification task with auditory color words (as primes) and visual color patches (as targets). Responses were faster for congruent priming, in comparison to neutral or incongruent priming. This effect also emerged for different levels of time compression of the auditory primes (to 30 % and 10 % of the original length; i.e., 120 and 40 ms) and turned out to be even more pronounced under high-perceptual-load conditions (Exps. 1 and 2). In Experiment 3, target-present or -absent decisions for brief target displays had to be made, thereby ruling out response-priming processes as a cause of the congruency effects. Nevertheless, target detection (d') was increased by congruent primes (30 % compression) in comparison to incongruent or neutral primes. Our results suggest semantic object-based auditory–visual interactions, which rapidly increase the denoted target object’s salience. This would apply, in particular, to complex visual scenes.     

Shifting attention into and out of objects: evaluating the processes underlying the object advantage

Visual cuing studies have been widely used to demonstrate and explore contributions from both object- and location-based attention systems. A common finding has been a response advantage for shifts of attention occurring within an object, relative to shifts of an equal distance between objects. The present study examined this advantage for within-object shifts in terms of engage and disengage operations within the object- and location-based attention systems. The rationale was that shifts of attention between objects require object-based attention to disengage from one object before shifting to another, something that is not required for shifts of attention within an object or away from a location. One- and two-object displays were used to assess object-based contributions related to disengaging and engaging attention within, between, into, and out of objects. The results suggest that the "object advantage" commonly found in visual cuing experiments in which shifts of attention are required is primarily due to disengage operations associated with object-based attention.     

Examining location-based and object-based components of inhibition of return in static displays

Tipper and Colleagues (e.g., Jordan & Tipper, 1998; Tipper, Driver, & Weaver, 1991; Tipper, Weaver, Jerreat, & Burak, 1994) have provided support for inhibition of return (IOR) being composed of a location-based and an object-based component. They were able to separate out the effects of locationbased and object-based IOR by using complex displays and displays that involved moving the cued object. The present study was designed to further examine the object- and location-based components of IOR in static displays. Three experiments were conducted that looked at the presence or absence of placeholder boxes on IOR. The first experiment was designed to replicate the results of Jordan and Tipper by presenting both objects and no-objects in the same display. In the second experiment, trials were blocked, and in the third experiment trials were presented in a random order. Overall, the results are inconsistent with the notion that independent object-based and location-based IOR components combine to produce the overall IOR effect and that additive effects are realized due to the context in which the trials are presented. We propose that a single inhibitory mechanism can account for the data.     

Examining location-based and object-based components of inhibition of return in static displays

Tipper and Colleagues (e.g., Jordan & Tipper, 1998; Tipper, Driver, & Weaver, 1991; Tipper, Weaver, Jerreat, & Burak, 1994) have provided support for inhibition of return (IOR) being composed of a location-based and an object-based component. They were able to separate out the effects of location-based and object-based IOR by using complex displays and displays that involved moving the cued object. The present study was designed to further examine the object- and location-based components of IOR in static displays. Three experiments were conducted that looked at the presence or absence of placeholder boxes on IOR. The first experiment was designed to replicate the results of Jordan and Tipper by presenting both objects and no-objects in the same display. In the second experiment, trials were blocked, and in the third experiment trials were presented in a random order. Overall, the results are inconsistent with the notion that independent object-based and location-based IOR components combine to produce the overall IOR effect and that additive effects are realized due to the context in which the trials are presented. We propose that a single inhibitory mechanism can account for the data.     

Stroop dilution depends on the nature of the color carrier but not on its location

Stroop dilution is the reduction of the Stroop effect in the presence of a neutral word. It has been attributed to competition for attention between the color word and neutral word, to competition between all stimuli in the visual field, and to perceptual interference. Five experiments tested these accounts. The critical manipulation was whether the color to be named was carried by the color word or the neutral word. Neutral words diluted the Stroop effect when they were the color carrier, but not when the color word was the color carrier. We argue that Stroop dilution is due to attentional competition between the color word and neutral word, with priority given to the color carrier.