Is the emotional Stroop task a special case of mood induction? Evidence from sustained effects of attention under emotion

Sustained effects of emotion are well known in everyday experience. Surprisingly, such effects are seldom recorded in laboratory studies of the emotional Stroop task, in which participants name the color of emotion and neutral words. Color performance is more sluggish with emotion words than with neutral words, the emotional Stroop effect (ESE). The ESE is not sensitive to the order in which the two groups of words are presented, so the effect of exposure to emotion words does not extend to disrupting performance in a subsequent block with neutral words. We attribute this absence of a sustained effect to habituation engendered by excessive repetition of the experimental stimuli. In a series of four experiments, we showed that sustained effects do occur when habituation is removed, and we also showed that the massive exposure to negative stimuli within the ESE paradigm induces a commensurately negative mood. A novel perspective is offered, in which the ESE is considered a special case of mood induction.     

Wheel chairs and arm chairs: A novel experimental design for the emotional Stroop effect

The emotional Stroop effect demonstrates that people are slower to name the ink colour of emotionally charged words than that of neutral words. Attributing this slowdown to emotionality or threat requires that the emotion and neutral words presented are equal on all extraneous variables. However, it is impossible in principle to match the two types of words on all conceivable variables. To address the problem, we presented the same set of words, polarised to be negative in one condition and neutral in another by using appropriate prime words that produced the desired valence through idiomatic two-word expressions. Across two studies, participants took longer to name the colour of the same words when they were rendered negative than when they were rendered neutral. This difference reflects a true emotional Stroop effect given the control provided for all potentially confounding variables tied to the target stimuli. The new procedure also enables researchers to calculate item-specific emotional Stroop effects for the first time.     

Depression impairs the ability to ignore the emotional aspects of facial expressions: Evidence from the Garner task

We assessed dysphoric and clinically distressed individuals' ability to ignore the emotional aspects of facial expressions using the Garner speeded‐classification task. Garner's paradigm tests the ability to selectively focus on a single relevant dimension while ignoring variations on other, irrelevant, ones. In the present task, the stimuli were faces of men and women expressing happy, angry, and neutral emotions. In Experiments 1 and 2, dysphoric and nondysphoric participants performed the Garner task, focusing on gender and ignoring emotion (Experiment 1) and focusing on emotion and ignoring gender (Experiment 2). Results suggest that dysphoric individuals exhibited more difficulty ignoring the emotional dimension of social stimuli even under specific instructions to do so than nondysphoric individuals. In Experiments 3 and 4, we replicated these results in clinically distressed and nondistressed individuals. The results of Experiment 3 further suggested that depression was more closely associated with the inability to selectively ignore emotion than was social anxiety. Experiment 4 confirmed that this failure of selective attention was specific to processing emotional, and not gender features. The implications of these findings for cognitive and interpersonal theories of depression are discussed.     

Differential impact of emotional task relevance on three indices of prioritised processing for fearful and angry facial expressions

It is commonly assumed that threatening expressions are perceptually prioritised, possessing the ability to automatically capture and hold attention. Recent evidence suggests that this prioritisation depends on the task relevance of emotion in the case of attention holding and for fearful expressions. Using a hybrid attentional blink (AB) and repetition blindness (RB) paradigm we investigated whether task relevance also impacts on prioritisation through attention capture and perceptual salience, and if these effects generalise to angry expressions. Participants judged either the emotion (relevant condition) or gender (irrelevant condition) of two target facial stimuli (fearful, angry or neutral) imbedded in a stream of distractors. Attention holding and capturing was operationalised as modulation of AB deficits by first target (T1) and second target (T2) expression. Perceptual salience was operationalised as RB modulation. When emotion was task-relevant (Experiment 1; N?=?29) fearful expressions captured and held attention, and were more perceptually salient than neutral expressions. Angry expressions captured attention, but were less perceptually salient and capable of holding attention than fearful and neutral expressions. When emotion was task-irrelevant (Experiment 2; N?=?30), only fearful attention capture and perceptual salience effects remained significant. Our findings highlight the importance for threat-prioritisation research to heed both the type of threat and prioritisation investigated.     

Effect of negative emotional content on working memory and long-term memory

In long-term memory, negative information is better remembered than neutral information. Differences in processes important to working memory may contribute to this emotional memory enhancement. To examine the effect that the emotional content of stimuli has on working memory performance, the authors asked participants to perform working memory tasks with negative and neutral stimuli. Task accuracy was unaffected by the emotional content of the stimuli. Reaction times also did not differ for negative relative to neutral words, but on an n-back task using faces, participants were slower to respond to fearful faces than to neutral faces. These results suggest that although emotional content does not have a robust effect on working memory, in some instances emotional salience can impede working memory performance.     

The emotional memory effect: Differential processing or item distinctiveness?

A color-naming task was followed by incidental free recall to investigate how emotional words affect attention and memory. We compared taboo, nonthreatening negative-affect, and neutral words across three experiments. As compared with neutral words, taboo words led to longer color-naming times and better memory in both within- and between-subjects designs. Color naming of negative-emotion nontaboo words was slower than color naming of neutral words only during block presentation and at relatively short interstimulus intervals (ISIs). The nontaboo emotion words were remembered better than neutral words following blocked and random presentation and at both long and short ISIs, but only in mixed-list designs. Our results support multifactor theories of the effects of emotion on attention and memory. As compared with neutral words, threatening stimuli received increased attention, poststimulus elaboration, and benefit from item distinctiveness, whereas nonthreatening emotional stimuli benefited only from increased item distinctiveness.     

Vivid: How valence and arousal influence word processing under different task demands

In this study, we used event-related potentials to examine how different dimensions of emotion—valence and arousal—influence different stages of word processing under different task demands. In two experiments, two groups of participants viewed the same single emotional and neutral words while carrying out different tasks. In both experiments, valence (pleasant, unpleasant, and neutral) was fully crossed with arousal (high and low). We found that the task made a substantial contribution to how valence and arousal modulated the late positive complex (LPC), which is thought to reflect sustained evaluative processing (particularly of emotional stimuli). When participants performed a semantic categorization task in which emotion was not directly relevant to task performance, the LPC showed a larger amplitude for high-arousal than for low-arousal words, but no effect of valence. In contrast, when participants performed an overt valence categorization task, the LPC showed a large effect of valence (with unpleasant words eliciting the largest positivity), but no effect of arousal. These data show not only that valence and arousal act independently to influence word processing, but that their relative contributions to prolonged evaluative neural processes are strongly influenced by the situational demands (and by individual differences, as revealed in a subsequent analysis of subjective judgments).     

Don't look now: Attentional avoidance of emotionally valenced cues

It is often assumed that emotional stimuli receive high priority for processing, and that the distinction between positive and negative valence is fundamental. However, studies of attention to symbolic stimuli, such as words of different valence, have proved inconclusive. In four experiments, control over the emotional attributes of previously neutral line sketches was achieved by associating them with valenced captions. When these newly valenced sketches were paired with neutral stimuli in an attentional search task, they elicited equivalent attentional avoidance. In contrast, in a final experiment, strongly valenced colour pictures captured attention. We suggest that a mechanism acting to limit unnecessary interruptions of ongoing behaviour can inhibit processing of relatively mild emotional stimuli.     

Implicit Memory and Anxiety: Perceptual Identification of Emotional Stimuli

The perceptual identification paradigm was used to examine implicit memory performance in high- and low-trait anxious subjects. A series of threat-related and neutral words was presented in different colours during the encoding phase. Subjects were required to encode the stimuli by naming the colour while ignoring the semantic content of the words (Experiment 1), by simply reading the words (Experiment 2) or by naming the colour of the words and the words themselves (Experiment 3). Experiment 1 demonstrated the predicted emotional Stroop effect, with high-trait subjects taking relatively longer than low-trait subjects to name the colour of the threat-related as compared to the neutral stimuli. All three experiments revealed a significant implicit memory effect overall, with more primed than unprimed words being correctly identified during the perceptual identification task. Subjects in all experiments also identified more of the threat-related than neutral words. Although Experiment 2 found that, overall, the high-trait subjects identified relatively fewer threat-related words than neutral words in comparison to the low-trait subjects, none of the experiments offered any support for the prediction of a threat-related implicit memory bias in hightrait anxiety.     

Where is the chocolate? Rapid spatial orienting toward stimuli associated with primary rewards

Some stimuli can orient attentional resources and access awareness even if they appear outside the focus of voluntary attention. Stimuli with low-level perceptual salience and stimuli with an emotional content can modulate attention independently of voluntary processes. In Experiment 1, we used a spatial cuing task to investigate whether stimuli that are controlled for their perceptual salience can modulate the rapid orienting of attention based exclusively on their affective relevance. Affective relevance was manipulated through a Pavlovian conditioning paradigm in which an arbitrary and affectively neutral perceptual stimulus was associated with a primary reward (i.e., a chocolate odor). Results revealed that, after conditioning, attentional resources were rapidly oriented toward the stimulus that was previously associated with the reward. In Experiment 2, we used the very same conditioning procedure, but we devaluated the reward after conditioning for half of the participants through a sensory-specific satiation procedure. Strikingly, when the reward was devaluated, attention was no longer oriented toward reward-associated stimuli. Our findings therefore suggest that reward associations rapidly modulate visual processing independently of both voluntary processing and the perceptual salience of the stimulus. This supports the notion that stimuli associated with primary rewards modulate rapid attention orienting on the basis of the affective relevance of the stimulus.     

How chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) perform in a modified emotional Stroop task

The emotional Stroop task is an experimental paradigm developed to study the relationship between emotion and cognition. Human participants required to identify the color of words typically respond more slowly to negative than to neutral words (emotional Stroop effect). Here we investigated whether chimpanzees (Pan troglodytes) would show a comparable effect. Using a touch screen, eight chimpanzees were trained to choose between two simultaneously presented stimuli based on color (two identical images with differently colored frames). In Experiment 1, the images within the color frames were shapes that were either of the same color as the surrounding frame or of the alternative color. Subjects made fewer errors and responded faster when shapes were of the same color as the frame surrounding them than when they were not, evidencing that embedded images affected target selection. Experiment 2, a modified version of the emotional Stroop task, presented subjects with four different categories of novel images: three categories of pictures of humans (veterinarian, caretaker, and stranger), and control stimuli showing a white square. Because visits by the veterinarian that include anaesthetization can be stressful for subjects, we expected impaired performance in trials presenting images of the veterinarian. For the first session, we found correct responses to be indeed slower in trials of this category. This effect was more pronounced for subjects whose last anaesthetization experience was more recent, indicating that emotional valence caused the slowdown. We propose our modified emotional Stroop task as a simple method to explore which emotional stimuli affect cognitive performance in nonhuman primates.     

Dissociations of personally significant and task-relevant distractors inside and outside the focus of attention: a combined behavioral and psychophysiological study

Studies of attentional capture by personally significant stimuli have reached inconsistent results, possibly because of improper control of the participants' attention. In the present study, the authors controlled visual attention by using a Stroop-like task. Participants responded to a central color and ignored a word presented either centrally (i.e., at the focus of attention) or peripherally (i.e., outside the focus of attention). Central words led to slower reaction times and larger orienting responses for significant items than for neutral items. These effects largely disappeared when the words appeared in a peripheral location. The peripheral words interfered with performance when they were relevant to task demands. These results indicate that there is a fundamental difference between task-relevant words and personally significant words: The former capture attention even when presented peripherally, whereas the latter do not.     

Emotional dilution of the Stroop effect: a new tool for assessing attention under emotion

In order to gauge in a precise fashion the capture of attention by emotional stimuli, we developed a new tool that imports the classic Stroop effect into the realm of emotion. Strooping the typical emotion tasks enabled the derivation of a pure intraitem measure of attention under emotion. The results of two experiments showed that the classic Stroop effects were smaller with emotion than with neutral words, demonstrating the power of emotion to bias attention. This emotional dilution of the Stroop effect can serve as a general-purpose tool for assessing attention under emotion.     

ERP evidence on the interaction between information structure and emotional salience of words

Both emotional words and words focused by information structure can capture attention. This study examined the interplay between emotional salience and information structure in modulating attentional resources in the service of integrating emotional words into sentence context. Event-related potentials (ERPs) to affectively negative, neutral, and positive words, which were either focused or nonfocused in question_–answer pairs, were evaluated during sentence comprehension. The results revealed an early negative effect (90–200 ms), a P2 effect, as well as an effect in the N400 time window, for both emotional salience and information structure. Moreover, an interaction between emotional salience and information structure occurred within the N400 time window over right posterior electrodes, showing that information structure influences the semantic integration only for neutral words, but not for emotional words. This might reflect the fact that the linguistic salience of emotional words can override the effect of information structure on the integration of words into context. The interaction provides evidence for attention–emotion interactions at a later stage of processing. In addition, the absence of interaction in the early time window suggests that the processing of emotional information is highly automatic and independent of context. The results suggest independent attention capture systems of emotional salience and information structure at the early stage but an interaction between them at a later stage, during the semantic integration of words.     

高低创造性思维水平者定向遗忘效应的差异研究

采用单字法定向遗忘范式,考察远距离联想任务得分高低者在中性和负性词语定向遗忘效应上的差异,来探讨创造性思维水平高低与主动抑制的关系。实验采用2(高/低创造性思维水平)×2(中性/负性词汇)×2(记住/忘记指令)×2(2s/5s时间间隔)混合设计,发现高低创造力组,在材料不同呈现时间下,对不同情绪材料的定向遗忘效应分别不同。低创者在2s和5s以及高创者在5s时间间隔时,均对中性词语表现出定向遗忘效应,而对负性词汇没有表现出明显的定性遗忘效应。高创者在2s时间间隔下,对中性和负性词语均表现出定向遗忘效应。结果表明较短时间内高创者对负性情绪的主动抑制能力优于低创者。     

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.     

Why does a red snake in the grass capture your attention?

It has been suggested that affective stimuli automatically capture attention; this preferential processing is thought to be related to the evolutionary significance of affective stimuli. However, recent evidence suggests that perceptual salience alone might explain why some affective stimuli are more likely to influence attentional processes in certain contexts. In this study, we manipulated affective and perceptual salience to better understand how affective information is processed and how it impacts attentional processes in different contexts. We used stimuli that are both affectively and perceptually salient, while varying the task requirement to encourage the processing of perceptually salient (Experiment 1) or affectively salient (Experiment 2) information. This design made it possible to observe independent and interdependent relationships between perceptual and affective salience. The results showed that when the task encouraged the processing of perceptually salient information, affective salience did not influence task performance. In contrast, when the task encouraged the processing of affectively salient information, affectively salient information impaired task performance. The findings suggest that the affective nature of the stimuli does not always influence attentional processes.     

中性抽象词和具体词情绪信息获得的差异

采用词汇迫选学习范式考察不同类型词汇获得情绪信息的认知机制。结果发现：（1）在迫选过程中与积极图片匹配的具体词汇喜好度显著高于与消极图片匹配的喜好度,而抽象词学习并未表现出这样的效应。（2）积极图片下被选择词汇的喜好度显著高于未被选择词汇的喜好度,而消极图片下被选择词汇与未被选择词汇的喜好度差异不显著。该结果表明具体词相较于抽象词更易获得相应情绪信息,积极情绪比消极情绪信息更易被习得。     

Spatial attention does improve temporal discrimination

It has recently been stated that exogenous attention impairs temporal-resolution tasks (Hein, Rolke, & Ulrich, 2006; Rolke, Dinkelbach, Hein, & Ulrich, 2008; Yeshurun, 2004; Yeshurun & Levy, 2003). In comparisons of performance on spatially cued trials versus neutral cued trials, the results have suggested that spatial attention decreases temporal resolution. However, when performance on cued and uncued trials has been compared in order to equate for cue salience, typically speed—accuracy trade-offs (SATs) have been observed, making the interpretation of the results difficult. In the present experiments, we aimed at studying the effect of spatial attention in temporal resolution while using a procedure to control for SATs. We controlled reaction times (RTs) by constraining the time to respond, so that response decisions would be made within comparable time windows. The results revealed that when RT was controlled, performance was impaired for cued trials as compared with neutral trials, replicating previous findings. However, when cued and uncued trials were compared, performance was actually improved for cued trials as compared with uncued trials. These results suggest that SAT effects may have played an important role in the previous studies, because when they were controlled and measured, the results reversed, revealing that exogenous attention does improve performance on temporal-resolution tasks.