Selective processing of threat cues in posttraumatic stress disorder.

Vietnam combat veterans with (n?=?15) and without (n?=?15) posttraumatic stress disorder (PTSD) performed a modified Stroop task in which they named the colors of neutral words (e.g., INPUT), positive words (e.g., LOVE), obsessive-compulsive disorder (OCD) words (e.g., GERMS), and PTSD words (e.g., BODYBAGS). In contrast to normal controls, PTSD patients took significantly longer to color-name PTSD words than to color-name neutral, OCD, and positive words. Because Stroop interference reflects involuntary semantic activation, it may provide a quantitative measure of intrusive cognitive activity, the hallmark symptom of PTSD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Skeletal Structure of Printed Words: Evidence From the Stroop Task.

Do readers encode the sequencing of consonant (C) and vowel (V) phonemes (skeletal structure) in printed words? The authors used the Stroop task to examine readers' sensitivity to skeletal structure. In Experiment 1, CVC nonwords (e.g., pof) facilitated the naming of colors with congruent frames (e.g., red, a CVC word) but not with incongruent ones (e.g., green). In Experiment 2, the color black (a CCVC frame) was named faster with a congruent CCVC frame (e.g., grof) compared to either CCVCC (e.g., groft) or CVC (e.g., gof) incongruent controls. Finally, in Experiment 3, the color pink (a CVCC frame) was named faster with a CVCC frame (e.g., goft) compared to either CCVCC or CVC incongruent controls. In most cases, congruent frames shared no segments with the color name. These findings demonstrate that readers automatically assemble the skeletal structure of printed words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Rational Look at the Emotional Stroop Phenomenon: A Generic Slowdown, Not a Stroop Effect.

The role of Stroop processes in the emotional Stroop effect was subjected to a conceptual scrutiny augmented by a series of experiments entailing reading or lexical decision as well as color naming. The analysis showed that the Stroop effect is not defined in the emotional Stroop task. The experiments showed that reading, lexical decision, and color naming all are slower with emotional words and that this delay is immune to task-irrelevant variation and to changes in the relative salience of the words and the colors. The delay was absent when emotional and neutral words appeared in a single block. A threat-driven generic slowdown is implicated, not a selective attention mechanism associated with the classic Stroop effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduced Stroop Interference for Opponent Colors May Be Due to Input Factors: Evidence From Individual Differences and a Neural Network Simulation.

Sensory or input factors can influence the strength of interference in the classic Stroop color-word task. Specifically, in a single-trial computerized version of the Stroop task, when color-word pairs were incongruent, opponent color pairs (e.g., the word BLUE in yellow) showed reduced Stroop interference compared with nonopponent color pairs (e.g., BLUE in red). In addition, participants' color discrimination ability was measured by standard color vision tests (i.e., Farnsworth-Munsell 100-Hue Test and Ishihara plates). Error rates in the Farnsworth-Munsell test correlated positively with the amount of Stroop interference. Neural network simulations (variants of J. D. Cohen, K. Dunbar, & J. L. McClelland's, 1990, model) showed that only a distributed trichromatic input layer was able to simulate these findings. Thus, sensory input from the color system needs to be incorporated into current accounts of the Stroop effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociating Stimulus-Stimulus and Response-Response Effects in the Stroop Task.

The separate semantic and response competition interactions between colour and word processing in a manual Stroop task were evaluated by comparing three trial types. Identity trials are both semantically compatible and response compatible (e.g., BLUE in the colour blue), different response trials are both semantically incompatible and response incompatible (e.g., BLUE in the colour green, where blue and green have different response keys), and same response trials are semantically incompatible and response compatible (e.g., the word BLUE in the colour red, where blue and red have the same key press response). Ink colours were embedded in two different word types, colour words, and colour associates. The results using colour words replicated the findings of De Houwer (2003) and demonstrated both a semantic effect (a difference between same response trials and identity trials) and response competition (a difference between same response trials and different response trials). In contrast, the results using colour associates provided evidence for only a semantic effect. These findings support interpretations of the colour associate Stroop effect that attribute the effect to semantics, but challenge Klein's (1964) response competition account and Sharma and McKenna's (1998) claim that the effect of colour associates is dependent on verbal responding. The results confirm that the Stroop colour-word task appears to involve at least two mechanisms, a semantic mechanism and a response competition mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions between color and word processing in a flanker task.

To examine interactions between color and word attributes, participants responded, either manually or vocally, to a central target (color patch or word) flanked by a Stroop stimulus. Color and word attributes of the flanker affected both vocal and manual responding to color patches. Color and word flankers also affected manual responding to word targets, but only word flanker affected vocal responding to word targets. These results are not consistent with models (e.g., translational models) of Stroop tasks, which posit that interactions between colors and words occur only when vocal responding is required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of listwide control, item-based control, and working memory capacity on Stroop performance.

Hypothesized top-down and bottom-up mechanisms of control within conflict-rich environments were examined by presenting participants with a Stroop task in which specific words were usually presented in either congruent or incongruent colors. Incongruent colors were either frequently (high contingency) or infrequently (low contingency) paired with the word. These items were embedded within lists consisting of either 100% congruent or 100% incongruent filler items to create mostly congruent or mostly incongruent lists. Results indicated a significant item-specific congruency effect, which was largest for high contingency responses and within mostly congruent lists. In addition, a significant listwide congruency effect was obtained, and this interacted with working memory capacity (WMC). There were larger listwide congruency effects for low WMC individuals. Finally, the pattern of Stroop interference across lists for low WMC individuals was dependent upon the congruency of the preceding trial. These results support multiple forms of cognitive control, as well as contingency learning, as mechanisms underlying proportion congruence effects in Stroop and other conflict tasks. These findings are interpreted within Braver, Gray, and Burgess's (2007) dual mechanisms of control theory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The Stroop effect: Why proportion congruent has nothing to do with congruency and everything to do with contingency.

The item-specific proportion congruent (ISPC) effect refers to the observation that the Stroop effect is larger for words that are presented mostly in congruent colors (e.g., BLUE presented 75% of the time in blue) and smaller for words that are presented mostly in a given incongruent color (e.g., YELLOW presented 75% of the time in orange). One account of the ISPC effect, the modulation hypothesis, is that participants modulate attention based on the identity of the word (i.e., participants allow the word to influence responding when it is presented mostly in its congruent color). Another account, the contingency hypothesis, is that participants use the word to predict the response that they will need to make (e.g., if the word is YELLOW, then the response is probably "orange"). Reanalyses of data from L. L. Jacoby, D. S. Lindsay, and S. Hessels (2003), along with results from new experiments, are inconsistent with the modulation hypothesis but entirely consistent with the contingency hypothesis. A response threshold mechanism that uses contingency information provides a sufficient account of the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and facilitation: Converging information versus inadvertent reading in Stroop task performance.

Disagreement exists about whether color–word Stroop facilitation is caused by converging information (e.g., Cohen et al., 1990; Roelofs, 2003) or inadvertent reading (MacLeod & MacDonald, 2000). Four experiments tested between these hypotheses by examining Stroop effects on response time (RT) both within and between languages. Words cannot be read aloud to produce facilitation between languages. Dutch–English bilingual participants named color patches while trying to ignore Dutch or English color words presented at a wide range of preexposure and postexposure stimulus onset asynchronies. The color patches were named in Dutch (Experiments 1 and 2) or English (Experiments 3 and 4). In all experiments, Stroop facilitation and interference effects were obtained in mean RTs with similar time courses within and between languages. Facilitation was generally present throughout the entire RT distributions. These results suggest that Stroop interference and facilitation have a common locus within and between languages, supporting the converging information hypothesis of Stroop facilitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Callosal involvement in a lateralized stroop task in alcoholic and healthy subjects.

To investigate the role of interhemispheric attentional processes, 25 alcoholic and 28 control subjects were tested with a Stroop match-to-sample task and callosal areas were measured with magnetic resonance imaging. Stroop color-word stimuli were presented to the left or right visual field (VF) and were preceded by a color cue that did or did not match the word's color. For matching colors, both groups showed a right VF advantage; for nonmatching colors, controls showed a left VF advantage, whereas alcoholic subjects showed no VF advantage. For nonmatch trials, VF advantage correlated with callosal splenium area in controls but not alcoholic subjects, supporting the position that information presented to the nonpreferred hemisphere is transmitted via the splenium to the hemisphere specialized for efficient processing. The authors speculate that alcoholism-associated callosal thinning disrupts this processing route. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic and controlled processing in Stroop negative priming: The role of attentional set.

The distinction between automatic and controlled attentional influences on priming effects was examined in a series of Stroop color-naming experiments. As expected, priming effects depended on the proportion of repeated trials-those in which a color word prime matched a following ink-color probe. However, responses were slower for repeated trials than for unrepeated trials when the proportion of repeated trials was no greater than chance (.25 with 4 colors). This effect was shown not to depend on slow-to-develop expectancies but did depend on the selective-attention requirements of the probe task. This dependence on probe task selection parallels an often reported result in the negative-priming literature (e.g., D. G. Lowe, 1979; S. P. Tipper & M. Cranston, 1985). Implications of these results for the distractor inhibition and episodic retrieval accounts of negative priming are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A confluence of contexts: Asymmetric versus global failures of selective attention to Stroop dimensions.

In 6 experiments probing selective attention through Stroop classification, 4 factors of context were manipulated: (a) psychophysical context, the distinctiveness of values along the color and word dimensions; (b) set size context, the number of stimulus values tested; (c) production context the mode used to respond; and (d) covariate context, the correlation between the dimensions. The psychophysical and production contexts mainly caused an asymmetry in selective attention failure between colors and words, whereas the set size and covariate contexts contributed primarily to the average or global magnitudes of attentional disruption across dimensions. The results suggest that (a) Stroop dimensions are perceptually separable, (b) J. R. Stroop's (1935) classic findings arose from his particular combination of contexts, and (c) stimulus uncertainty and dimensional imbalance are the primary sources of task and congruity effects in the Stroop paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Volitional facilitation of difficult intentions: Joint activation of intention memory and positive affect removes Stroop interference.

Removal of Stroop interference was obtained after exposure to words eliciting positive affect. This effect was predicted by personality systems interactions (PSI) theory, which assumes that (a) an abstract (high-level) representation of a difficult intention is generated in intention memory under certain conditions (e.g., when an action plan contains more than 1 step); (b) positive affect releases the inhibition of the pathway between intention memory and its output system. Interference removal is interpreted in terms of volitional facilitation. This effect posits a challenge to current cognitive models of the Stroop effect. Compared with alternative explanations, PSI theory can explain the data in a broader context: Implications of volitional facilitation and volitional inhibition for the study of prospective memory, alienation, procrastination, and rumination in depression are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional Bias and Drinking to Cope With Social Anxiety.

This study investigated the sensitivity of the emotional Stroop test for identifying individuals who reported drinking to cope with social fears. Community volunteers completed a modified Stroop task during which social threat, alcohol-related, and control words were presented. High scores on drinking-to-cope measures were hypothesized to be associated with longer response latencies to both social threat and alcohol-related words. Consistent with previous studies, alcohol dependence was correlated with latencies for alcohol-related words, and level of social anxiety was correlated with response latency to social threat words. As expected, drinking-to-cope measures predicted response latency to alcohol-related and social threat words. These results suggest that the emotional Stroop test is useful in studying the relationship between social anxiety and alcohol consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric interactions during a face–word Stroop-analog task.

A Stroop-analog task with faces and words was developed to investigate intrahemispheric and interhemispheric Stroop effects (SEs). Lateralized faces and words were used in an attempt to invoke right- and left-hemispheric specialization, respectively. A prototypical male face, female face, and baby face and the corresponding words man, woman, and baby were presented as congruent or incongruent face-word pairs either to the same visual field (i.e., unilateral presentations) or to separate visual fields (i.e., bilateral presentations). Bidirectional SEs were found. Word distractors interfered with the identification of face targets, and, somewhat surprisingly, an even greater SE was obtained when words were the target and faces were ignored. Laterality effects were most pronounced for bilateral trials, whereby the SE was larger for right-hemisphere than for left-hemisphere target presentations, irrespective of type of target. This finding suggests that the left hemisphere is generally better shielded than the right from interhemispheric interference effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subliminal processing of emotional information in anxiety and depression.

Investigated selective processing of emotional information in anxiety and depression using a modified Stroop color naming task. 19 anxious, 18 depressed, and 18 normal control Ss were required to name the background colors of anxiety-related, depression-related, positive, categorized, and uncategorized neutral words. Half of the words were presented supraliminally, half subliminally. Anxious Ss, compared with depressed and normal Ss, showed relatively slower color naming for both supraliminal and subliminal negative words. The results suggest a preattentive processing bias for negative information in anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic processing of psychological distance: Evidence from a Stroop task.

A picture-word version of the Stroop task was used to test the automatic activation of psychological distance by words carrying various senses of psychological distance: temporal (tomorrow, in a year), social (friend, enemy), and hypotheticality (sure, maybe). The pictures implied depth, with the words appearing relatively close to or distant from the observer. The participants classified the spatial distance of words faster when the word's implicit psychological distance matched its spatial distance (e.g., a geographically close word was classified faster when it was "friend" than when it was "enemy"). The findings are consistent with the idea that psychological distance is accessed automatically, even when it is not directly related to people's current goals, and suggest that psychological distance is an important dimension of meaning, common to spatial distance, temporal distance, social distance, and hypotheticality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference effects in the Stroop and Simon paradigms.

The possibility that Stroop and Simon effects reflect the same cognitive processes was tested in 3 experiments with 62 adult Ss. The words LEFT and RIGHT were shown left and right of screen center. Similar levels of interference were found for a Simon task (keypress to meaning of word) and a spatial Stroop task (name its location). A reverse Simon task (keypress to word location) showed minimal interference from the irrelevant word, but in a reverse spatial Stroop task (read the word aloud) interference from the irrelevant location was sizeable. This poses difficulty for translational accounts of Stroop interference. Presenting LEFT and RIGHT laterally balanced by a color-name foil yielded a Simon effect inconsistent with an orienting response hypothesis. With bilateral stimuli in a reverse Simon task, interference was marked, supporting an integrative account of Stroop and Simon effects in terms of cognitive activation and the salience of irrelevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The emotional Stroop task and psychopathology.

Attentional bias is a central feature of many cognitive theories of psychopathology. One of the most frequent methods of investigating such bias has been an emotional analog of the Stroop task. In this task, participants name the colors in which words are printed, and the words vary in their relevance to each theme of psychopathology. The authors review research showing that patients are often slower to name the color of a word associated with concerns relevant to their clinical condition. They address the causes and mechanisms underlying the phenomenon, focusing on J. D. Cohen, K. Dunbar, and J. L. McClelland's (see record 1990-27437-001) parallel distributed processing model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)