The reverse Stroop effect

In classic Stroop interference, manual or oral identification of sensory colors presented as incongruent color words is delayed relative to simple color naming. In the experiment reported here, this effect was shown to all but disappear when the response was simply to point to a matching patch of color. Conversely, strong reverse Stroop interference occurred with the pointing task. That is, when the sensory color of a color word was incongruent with that word, responses to color words were delayed by an average of 69 msec relative to a word presented in gray. Thus, incongruently colored words interfere strongly with pointing to a color patch named by the words, but little interference from incongruent color words is found when the goal is to match the color of the word. These results suggest that Stroop effects arise from response compatibility of irrelevant information rather than automatic processing or habit strength.     

Stroop effects in bilingual translation

In two experiments, bilinguals proficient in English and Spanish translated words from one language to the other. In each experiment, following the target word to be translated, distractor words were presented after a short (200-msec) or long (500-msec) stimulus onset asynchrony. In Experiment 1, the distractor words appeared in the language of production and were related to the meaning or form of the spoken translation. The results replicated past studies in demonstrating that semantically related distractor words produced Stroop-type interference, whereas form-related distractor words produced facilitation. In Experiment 2, the distractors appeared in the language of input and were related to the meaning or form of the target word itself. In contrast to the results of Experiment 1, there were only marginal effects of the distractors on translation performance. These results suggest that language cues related to the nature of the input in translation may serve to reduce competition among lexical competitors during lexicalization. The contrast between these results and those in bilingual picture-word interference studies provides important constraints for models of language production and for claims about the locus of language selection.     

Translation and competition among internal representations in a reverse Stroop effect

In two experiments, the contributions of internal and external competition in a task known to produce a reverse Stroop effect were investigated. In this paradigm, the verbal meaning of an incongruent Stroop stimulus is identified by pointing to a patch of matching color--a task made difficult by the incongruent print color. The experiments showed that there was somewhat more interference when the (irrelevant) color in which the target word was printed was available as an alternate response patch than when it was not. However, significantly more interference was determined by whether the (irrelevant) print color belonged to the set of colors actually used as target words in the course of the experiment. Moreover, the same patterns of interference emerged when the task was altered so that the mere presence of the correct color had to be indicated with a keypress, rather than by pointing to the color's location. Consistent with translation models of Stroop interference, these results demonstrate the theoretical importance of competition among internal representations, rather than among stimuli or responses.     

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.     

Increased Stroop interference with better second-language reading skill

Skilled readers demonstrate remarkable efficiency in processing written words, unlike beginning readers for whom reading occurs more serially and places higher demands on visual attention. In the present study, we used the Stroop paradigm to investigate the relationship between reading skill and automaticity, in individuals learning a second language with a different orthographic system. Prior studies using this paradigm have presented a mixed picture, finding a positive, a negative, or no relationship between the size of Stroop interference and reading skills. Our results show that Stroop interference in the second language was positively related to reading skill (when controlled for interference in the first language). Furthermore, interference was positively related to objective but not subjective indices of the amount of exposure to the second language. We suggest that the lack of consistency in the results of earlier studies may be due, at least in part, to these studies looking at Stroop interference in isolation, rather than comparing interference between languages.     

Word reading practice reduces Stroop interference in children

Stroop interference is thought to index reading automaticity and is expected to increase with reading practice and to decrease with improved color naming. We investigated the effects of practice in word reading and color naming on interference in 92 adults and 109 children in Grades 4–5. For children, interference was reduced after reading practice with color words. In neither group was interference affected by practice in color naming of neutral stimuli. These findings are consistent with a direct negative relationship between reading ability and interference and challenge the automaticity account in favor of a blocking mechanism whereby interference is determined by the delay to inhibit the reading response rather than by the efficiency of color naming.     

Increased Stroop interference with better second-language reading skill

Skilled readers demonstrate remarkable efficiency in processing written words, unlike beginning readers for whom reading occurs more serially and places higher demands on visual attention. In the present study, we used the Stroop paradigm to investigate the relationship between reading skill and automaticity, in individuals learning a second language with a different orthographic system. Prior studies using this paradigm have presented a mixed picture, finding a positive, a negative, or no relationship between the size of Stroop interference and reading skills. Our results show that Stroop interference in the second language was positively related to reading skill (when controlled for interference in the first language). Furthermore, interference was positively related to objective but not subjective indices of the amount of exposure to the second language. We suggest that the lack of consistency in the results of earlier studies may be due, at least in part, to these studies looking at Stroop interference in isolation, rather than comparing interference between languages.     

A reach-to-touch investigation on the nature of reading in the Stroop task

In a Stroop task, participants can be presented with a color name printed in color and need to classify the print color while ignoring the word. The Stroop effect is typically calculated as the difference in mean response time (RT) between congruent (e.g., the word RED printed in red) and incongruent (GREEN in red) trials. Delta plots compare not just mean performance, but the entire RT distributions of congruent and incongruent conditions. However, both mean RT and delta plots have some limitations. Arm-reaching trajectories allow a more continuous measure for assessing the time course of the Stroop effect. We compared arm movements to congruent and incongruent stimuli in a standard Stroop task and a control task that encourages processing of each and every word. The Stroop effect emerged over time in the control task, but not in the standard Stroop, suggesting words may be processed differently in the two tasks.     

A developmental study of the auditory Stroop effect

A pediatric auditory version of the Stroop procedure was developed and administered to 48 normal children from 3 to 6 years of age. Our purpose was to define the developmental course characterizing interaction between auditory and semantic speech dimensions in young children. The procedure was a reaction time (RT) task that required children to respond as quickly and as accurately as possible to words spoken by a male or a female voice. Children were instructed to ignore what was said and to push the "Mommy" button if Mommy was talking or the "Daddy" button if Daddy was talking. Performance was obtained for words with neutral, congruent, and conflicting semantic content. Preschool children manifested processing dependencies that were similar to those observed in adults on the visual Stroop procedure. Conflict between semantic and auditory dimensions significantly increased RT and congruence between the two dimensions significantly decreased RT relative to the neutral condition. The pattern of results indicated that the meaning of words was processed automatically in the normal children. The magnitude of the Stroop effect reflected developmental change with increasing age.     

Phonetic recoding and reading difficulty in beginning readers

The results of a recent study (Liberman, Shankweiler, Liberman, Fowler, & Fischer, 1977) suggest that good beginning readers are more affected than poor readers by the phonetic characteristics of visually presented items in a recall task. The good readers made significantly more recall errors on strings of letters with rhyming letter names than on nonrhyming sequences; in contrast, the poor readers made roughly equal numbers of errors on the rhyming and nonrhyming letter strings. The purpose of the present study was to determine whether the interaction between reading ability and phonetic similarity is solely determined by different rehearsal strategies of the two groups. Accordingly, good and poor readers were tested on rhyming and nonrhyming words using a recognition memory paradigm that minimized the opportunity for rehearsal. Performance of the good readers was more affected by phonetic similarity than that of the poor readers, in agreement with the earlier study. The present findings support the hypothesis that good and poor readers do differ in their ability to access a phonetic representation.     

Decomposing the emotional Stroop effect

The emotional Stroop effect refers to the phenomenon that participants are faster in responding to the ink colour of neutral than of negative word stimuli, possibly reflecting fast and automatic allocation of attention towards negative stimuli. However, this interpretation was challenged by McKenna and Sharma (2004) McKenna, F. P. and Sharma, D. 2004. Reversing the emotional Stroop effect reveals that it is not what it seems: The role of fast and slow components. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30: 382–392. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] who found that the emotional Stroop effect reflected a generic slowdown after negative stimuli. In fact, they even found reversed effects in a design in which neutral stimuli more often followed negative stimuli and vice versa. Yet, besides reversing the emotional Stroop effect this contingency might in fact have counteracted the fast effect, which was usually interpreted as the emotional Stroop effect. To decompose the emotional Stroop effect we used a design in which the foregoing and the current valence were uncorrelated and in which the fast and slow effects could be computed independently from each other. We found evidence for both fast and slow effects and discuss the practical implications for researchers using the emotional Stroop task as a measurement and the theoretical implications for researchers interested in the underlying cognitive mechanisms that contribute to the emotional Stroop effect.     

Phonology in the bilingual Stroop effect

In a bilingual Stroop task, we examined between-language interference among proficient Japanese-English bilingual speakers. Participants named ink colors either in Japanese or in English. The Japanese color terms were either phonologically similar to (i.e., loan words) or dissimilar from (i.e., traditional color terms) English color terms. For both response languages, a significant between-language Stroop effect was found despite the orthographic dissimilarity between the languages. The magnitude of the between-language interference was larger with the phonologically similar terms. These findings implicate direct links connecting phonologically similar matching words in the lexicons of proficient bilingual speakers of dissimilar languages and imply that phonological processing in lexical access occurs even when the access is done unintentionally.     

A reversal of the Stroop interference effect,through scanning:

Interference on the Stroop test has been explained on the basis of a stronger habit (word reading) interfering with a weaker one (color naming) on an incongruous color-word (CW) card. Since scanning for words is slower (weaker) than scanning for colors, it was predicted that making the Stroop a scanning task would produce more interference with scanning for words rather than colors on the CW card. This prediction was confirmed. In addition, analyses of individual differences offered some support for differential habit-strength theories of Stroop interference. However, differences between the standard and scanning Stroop tests suggested that some kind of information-processing analysis would be more fruitful.     

Upper-left gaze bias reveals competing search strategies in a reverse Stroop task

Three experiments with a total of 87 human observers revealed an upper-left spatial bias in the initial movement of gaze during visual search. The bias was present whether or not the explicit control of gaze was required for the task. This bias may be part of a search strategy that competed with the fixed-gaze parallel search strategy hypothesized by Durgin [Durgin, F. H. (2003). Translation and competition among internal representations in a reverse Stroop effect. Perception &Psychophysics, 65, 367-378.] for this task. When the spatial probabilities of the search target were manipulated either in accord with or in opposition to the existing upper-left bias, two orthogonal factors of interference in the latency data were differentially affected. The two factors corresponded to two different forms of representation and search. Target probabilities consistent with the gaze bias encouraged opportunistic serial search (including gaze shifts), while symmetrically opposing target probabilities produced latency patterns more consistent with parallel search based on a sensory code.     

The picture-word interference effect is not a Stroop effect

A psychological refractory period (PRP) paradigm was used to isolate the locus of the picture-word interference effect along the chain of processes subtended in name production. Two stimuli were presented sequentially on each trial, separated by a varying stimulus onset asynchrony (SOA). The first stimulus, SI, was a tone that required a manual response. The second stimulus, S2, was a picture-word stimulus associated with picture naming. The distractor word was conceptually related to the picture on half of the trials, and unrelated in the other trials. A picture-word interference effect was found at long SOA, but not at short SOA. Such underadditive interaction between SOA and semantic relatedness suggests strongly that the locus of the picture-word interference effect is functionally earlier than the PRP effect locus. The results are discussed in relation to models of word production suggesting the involvement of central mechanisms in the selection of lexical output.     

Developmental change in the cross-modal Stroop effect

E. M. Elliott, Cowan, and Valle-Inclan (1998) reported a cross-modal Stroop-like interference effect in adults when an auditory distractor (a color or noncolor word) occurred simultaneously with a color patch to be named. Response times were slower with color as opposed to noncolor distractors. To distinguish two accounts of this phenomenon, we tested 4- to 11-year-olds and adults. The suppression hypothesis posits that the irrelevant word enters a phonological buffer and is injurious to color naming if the participant is unable to suppress its representation in time. The concurrent processing hypothesis states that interference occurs when the distractor and the color name are lexically accessed at the same time. Our finding that the cross-modal Stroop effect occurred in young children even with a distractor presented 500 msec in advance of the color patch favors the suppression account. Development in executive functioning may also contribute to the interference effect's becoming progressively weaker with age.