Selective processing of food,weight, and body-shape words in nonpatient women with bulimia nervosa: Interference on the Stroop task

The study investigated whether the Stroop interference effect could be found in nonpatients with a self-report consistent with a diagnosis of bulimia nervosa. The nonpatient bulimic group showed significantly more interference to disorder-specific words (food, weight, and body shape) than to control words. The two nonpatient comparison groups, a depressed-nonbulimic group and a nonbulimic-nondepressed group, showed no interference. These results indicate that nonpatients with bulimia nervosa can be used to test various models of the cognitive and emotional processes involved in bulimia nervosa with the modified Stroop task. Methodological issues in the use of the computerized Stroop task with clinical populations are also noted.     

The influence of attentional control on stimulus processing is category specific in Stroop tasks

It is still unclear how attentional control influences stimulus processing. We investigated this issue in four Stroop task experiments utilizing a pretest–training–posttest design. Subjects were given extensive training on the Stroop task using typical incongruent Stroop trials. The rates of color naming and word reading, which reflect the efficiency of stimulus processing, were assessed in pretest and posttest. The difference in rates between posttests and pretests reflects the influence of attentional control, acquired during the training phase, on stimulus processing. In Experiment 1, members of color category were used in the training phase; in Experiment 2, members of color category were used, but not in the training phase; in Experiment 3, they were neither in the color category nor were they used in the training. The results consistently showed that the suppression of word reading and the enhancement of color naming were developed in the training phases and they were not due to general training of color-naming task without conflict but to color-naming training with Stroop conflict (Experiment 4). More importantly, both suppression and enhancement affected the members of color category regardless of whether they were trained or not. The present findings suggest that the influence of attentional control on stimulus processing is category specific. We discuss the implications of the present results in terms of existing research on the locus of attentional control in Stroop tasks.     

What is the nature of increased Stroop interference in schizophrenia?

In comparison to controls, patients with schizophrenia classically display (1) an overall slowing in response times (RTs) and (2) a disproportionate slowing in RTs in the conflict condition of the Stroop color/word interference task. These two effects appear repeatedly in the card version of the Stroop task but were not replicated in a number of studies using a computer item-by-item version of the task. The present study was aimed at understanding the exact nature of the increased interference classically found in the performance of patients with schizophrenia in the card version of the Stroop task. We used a computer trial-by-trial version in which we investigated the effects of two major methodological differences between the two versions: (1) blocked (card version) versus mixed (computer version) presentation of the neutral, congruent and conflict conditions and (2) presence (card version) versus absence (computer version) of distractors in the spatial surrounding of the target. We found an overall slowing in performance and a disproportionate slowing in the conflict condition for patients with schizophrenia but only when the target was surrounded by distractors (in Experiments 2 and 3). The data are discussed in terms of a deficit in selective attention and inhibitory processes in schizophrenia.     

Body images of patients with anorexia nervosa, bulimia nervosa and female control subjects: a comparison with male ideals of female attractiveness

Body images of female patients with anorexia nervosa and bulimia nervosa were assessed against females without eating disorders and compared with male ideals of female attractiveness. A computer program was applied to examine body images of 62 patients with anorexia nervosa, 45 patients with bulimia nervosa, and 40 female and 39 male control subjects. Body size overestimation was most distinct in the two patient groups. Self-ideal discrepancy was highest in bulimia nervosa. Estimation of the society's ideal female body in all three female groups did not differ from men's perception of the most attractive female body. Congruence of ideals of female attractiveness in patients, female, and male control subjects and described differences between patients and female controls support the theory that body image disturbance is a problem of processing self-referential information regarding body image rather than a problem of processing body image related information per se.     

One night of sleep deprivation affects reaction time, but not interference or facilitation in a Stroop task

The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results often do not differentiate between general effects of sleep deprivation on performance and effects specifically on interference in the Stroop task. To examine the effect of prolonged wakefulness on performance on the Stroop task, we studied participants in a 40-h "constant routine" protocol during which they remained awake in constant conditions and performed a Stroop color-naming task every two hours. We found that reaction time was slowest when the color and word did not match (incongruent), fastest when the color and word did match (congruent), and intermediate when participants named the color of the non-word stimulus (neutral). Performance on all three trial types degraded significantly as a function of time awake. Extended wakefulness did not significantly change the additional time needed to respond when the color and word did not match (Stroop interference), nor did it change the amount of facilitation when color and word matched. These results indicate that one night of sleep deprivation influences performance on the Stroop task by an overall increase in response time, but does not appear to impact the underlying processes of interference or facilitation. The results suggest that the degree to which an "executive function" is affected by sleep deprivation may depend on the particular executive function studied and the degree to which it is subserved by the prefrontal cortex.     

Time course analysis of the Stroop phenomenon

Dyer (1971) investigated the response competition hypothesis of the Stroop phenomenon by temporally separating the color and word components of single stimuli (incongruent, control, and congruent). This line of research was continued in a series of five experiments that generalized Dyer's study: (a) In addition to the color-naming task, a reading task was included; (b) the irrelevant stimulus component was presented before and after the relevant one; (c) the probabilities of congruent and incongruent stimuli were varied; (d) besides color-word/color stimuli, color-color and word-word stimuli were used; and (e) the functional discrimination (color naming or reading) was compared with a sequential discrimination task. The data suggest the following temporal relations: (a) a slow facilitation due to response bias; (b) its inhibitory counterpart; and (c) a fast, strong inhibition with no facilitatory complement that seems to correspond to the usual Stroop conflict but that seems to occur earlier than the response execution stage.     

Role of Gestalt grouping in selective attention: evidence from the Stroop task

Selective attention has been intensively studied using the Stroop task. Evidence suggests that Stroop interference in a color-naming task arises partly because of visual attention sharing between color and word: Removing the target color after 150 msec reduces interference (Neumann, 1986). Moreover, removing both the color and the word simultaneously reduces interference less than does removing the color only (La Heij, van der Heijden, & Plooij, 2001). These findings could also be attributed to Gestalt grouping principles, such as common fate. We report three experiments in which the role of Gestalt grouping was further investigated. Experiment I replicated the reduced interference, using words and color patches. In Experiment 2, the color patch was not removed but only repositioned (<2 degrees) after 100 msec, which also reduced interference. In Experiment 3, the distractor was repositioned while the target remained stationary, again reducing interference. These results indicate a role for Gestalt grouping in selective attention.     

Color-object interference in young children: A Stroop effect in children 3½-6½ years old

The Stroop color–word task cannot be administered to children who are unable to read. However, our color–object Stroop task can. One hundred and sixty-eight children of 3½–6½ years (50% female; 24 children at each 6-month interval) were shown line drawings of familiar objects in a color that was congruent (e.g., an orange carrot), incongruent (e.g., a green carrot), or neutral (for objects having no canonical color [e.g., a red book]), and abstract shapes, each drawn in one of six colors. Half the children were asked to name the color in which each object was drawn, and half were to name each object. Children's predominant tendency was to say what the object was; when instructed to do otherwise they were slower and less accurate. Children were faster and more accurate at naming the color of a stimulus when the form could not be named (abstract shape) than when it could, even if in its canonical color. The heightened interference to color-naming versus object-naming was not due to lack of familiarity with color names or group differences: Children in the color condition were as fast and accurate at naming the colors of abstract shapes as were children in the form condition at naming familiar objects.     

Pupillary Stroop effects

We recorded the pupil diameters of participants performing the words’ color-naming Stroop task (i.e., naming the color of a word that names a color). Non-color words were used as baseline to firmly establish the effects of semantic relatedness induced by color word distractors. We replicated the classic Stroop effects of color congruency and color incongruency with pupillary diameter recordings: relative to non-color words, pupil diameters increased for color distractors that differed from color responses, while they reduced for color distractors that were identical to color responses. Analyses of the time courses of pupil responses revealed further differences between color-congruent and color-incongruent distractors, with the latter inducing a steep increase of pupil size and the former a relatively lower increase. Consistent with previous findings that have demonstrated that pupil size increases as task demands rise, the present results indicate that pupillometry is a robust measure of Stroop interference, and it represents a valuable addition to the cognitive scientist’s toolbox.     

Suppression-induced hyperaccessibility of thoughts in abstinent alcoholics: a preliminary investigation

Abstinent alcoholics were compared to a non-alcoholic control group on a modified Stroop color-naming task. Alcoholics took significantly longer to name the color of the word "alcohol" than to name the color of non-alcohol words (i.e., they showed an interference effect) after they had first tried to suppress thoughts of alcohol. Alcoholics who had freely expressed thoughts about alcohol prior to the Stroop did not show such interference. Control participants who had suppressed thoughts of alcohol showed no interference effect. The results overall suggest that when alcoholics try to suppress thoughts of alcohol, these thoughts may become hyperaccessible immediately afterward.     

Verbal coding and the elimination of Stroop interference in a matching task

Translational models of the Stroop effect (Virzi & Egeth, 1985) predict that Stroop interference can be eliminated if subjects can be induced to process target colors using a coding system separate from the coding system used to process distractors. This hypothesis was tested in two experiments. In the first experiment, we attempted to eliminate the need for subjects to translate target colors to verbal codes when responding to Stroop stimuli. Before responding to verbal incongruent color word distractors, subjects practiced matching colors to irregular shapes. It was expected that subjects would use nonverbal codes to mediate responding in this task. After practice, subjects continued the matching task in the presence of incongruent color words. Stroop interference persisted, contrary to predictions. Because subjects reported adopting verbal strategies to perform the matching task, Experiment 2 was designed to control the verbal coding strategies that subjects employed. Before responding to Stroop distractor stimuli, subjects in the nonsense name group practiced using nonsense names to mediate the matching of shapes to colors; subjects in the actual name group used actual color names to mediate performance in the matching task. When incongruent color word distractors were introduced, Stroop interference was eliminated for subjects in the nonsense name group, but persisted for subjects in the actual name group. The results are interpreted as consistent with an outcome conflict (Navon & Miller, 1987) or a modified translational model of the Stroop effect.     

Psychological responses to body shape exposure in patients with bulimia nervosa

One of the unresolved issues regarding research on bulimia nervosa concerns the question as to how patients diagnosed with bulimia nervosa respond to body image exposure. In addition, it remains unclear whether there are differential responses associated with different exposure techniques (e.g. in vivo exposure vs. exposure by visualization). The aim of the present study was to investigate psychological responses to body image exposure. Twenty participants diagnosed with bulimia nervosa (DSM IV) and twenty non-eating disordered individuals were exposed to their body image using a video recording (video confrontation). In addition, they were asked to imagine and describe the appearance of their body (imagery task). Results indicate that self-reported negative emotions increased in response to both, video confrontation and imagery task, in the clinical as well as in the control group. Furthermore, video confrontation led to more pronounced group differences than exposure by visualization (imagery task). Participants diagnosed with bulimia nervosa took less time to describe their waist, hips and bottom compared to non-eating disturbed controls. This last result could be interpreted in terms of avoidance behavior and other mechanisms during body image exposure.     

Dilution of compatibility effects in Simon-type tasks depends on categorical similarity between distractors and diluters

The presence of a distracting stimulus during performance of the Stroop color-naming task leads to dilution of the Stroop effect. Because the automatic activation of word meaning may interfere with the task-relevant stimulus feature (text color; stimulus-stimulus [S-S] interference) and the response (saying the text color; stimulus-response [S-R] interference), it is unclear which of these types of interference is diluted. We introduce a new dilution paradigm using word- and arrow-based Simon tasks, in which only S-R interference is present. Participants made a left or right response to a central color target. A task-irrelevant location-word (Experiment 1) or arrow (Experiment 2) distractor adjacent to the target produced S-R compatibility effects. An additional neutral word or symbol series (diluter) was sometimes presented on the opposite side of the target from the distractor. The compatibility effect was smaller when the distractor and diluter category domains matched than when they mismatched. This result provides evidence that S-R compatibility effects are susceptible to the presence of diluters that are categorically similar to the distractors.     

Enduring cognitive dysfunction in unipolar major depression: A test–retest study using the Stroop paradigm

Hammar, Å., Sørensen, L., Årdal, G., Oedegaard, K.J., Kroken, R., Roness, A. & Lund, A. (2009). Enduring cognitive dysfunction in unipolar major depression: A test–retest study using the Stroop‐paradigm. Scandinavian Journal of Psychology. The aim of the study was to investigate automatic and effortful information processing with the Stroop paradigm in a long term perspective in patients with major depressive disorder (MDD). Patients were tested at two test occasions: at inclusion with a Hamilton Depression Rating Scale (HDRS) score >18, and after 6 months, when most patients had experienced symptom reduction. The Stroop paradigm is considered to measure aspects of attention and executive functioning and consists of three conditions/cards: naming the color of the patches (Color), reading of the color‐words (Word) and naming the ink color of color‐words (Color‐Word). The Color‐Word condition is proved to be the most cognitive demanding task and requires the proband to actively suppress interference and is therefore considered to require more effortful information processing, whereas naming the color of the patches and reading the color‐words are expected to be more automatic and less cognitive demanding. A homogenous group of 19 patients with unipolar recurrent MDD according to DSM‐IV and a HDRS score of >18 were included in the study. A control group was individually matched for age, gender and level of education. Depressed patients performed equal to the control group on the Color and Word cards at both test occasions. However, the patients were impaired compared with the control group on the Color‐Word card task at both test occasions. Thus, the depressed patients showed no improvement of effortful attention/executive performance as a function of symptom reduction. The results indicate that the depressed patients showed impaired cognitive performance on cognitive demanding tasks when symptomatic and that this impairment prevailed after 6 months, despite significant improvement in their depressive symptoms.     

Cognitive control in children: stroop interference and suppression of word reading

The development of cognitive control and its relation to overcoming Stroop interference was assessed in a sample (N= 65) of elementary-school children. Subjects alternately performed Stroop color-naming trials and word-reading trials. In separate blocks, the colored Stroop items were non-color words (incongruent condition) or rows of asterisks (neutral condition). Younger children showed both larger Stroop interference in error rates and a greater slowing of word reading in the incongruent condition compared with older children. We conducted analyses of response time distributions that assessed the degree of word-reading suppression applied by younger and older children. Surprisingly, these analyses indicated that younger children engaged in stronger suppression than older children. We propose that greater Stroop interference among younger children is not due to lack of ability to suppress word reading, but instead is the result of a failure to consistently maintain the task set of color naming.     

Associative priming in color naming: interference and facilitation

In Experiment 1, color-naming interference for target stimuli following associated primes was greater in a group making a lexical decision to the prime than in a group reading the prime silently. High-frequency targets were responded to more quickly than low-frequency targets. In Experiment 2, with subjects naming the prime, there was evidence of associative interference when the prime and the target were grouped temporally but not when the intertrial interval was comparable with the prime-target interval. Associative primes presented at a short (120-msec) prime-target stimulus onset asynchrony facilitated color naming in Experiment 3. Taken together, the results suggest that the effect of faster processing of the base word in a color-naming task is facilitatory and that color-naming priming interference arises when associative prime processing increases conflict between word and color responses by enhancing phonological or articulatory activation of the base word.     

Selective information processing and schematic content related to eating behavior

An adaptation of the Stroop color-naming task was used to investigate selective information processing related to eating behavior in 90 undergraduate women. This study differed from previous studies by (a) treating eating behavior as a continuous variable and (b) looking at five separate categories of words including color, neutral, food, body shape, and other emotionally salient words. We did not find a strong pattern of relation between the Stroop task and eating and body image measures. Results suggest that in a nonclinical population, direct methods of accessing cognitions related to eating may be more fruitful than indirect measures.     

用PDP模型模拟Stroop任务的实验研究

本实验用基于ＰＤＰ原理构造的Ｓｔｒｏｏｐ任务模型模拟了Ｓｔｒｏｏｐ颜色－词的干扰现象。模型采用ＢＰ学习算法。经过训练,模型学会字词阅读和颜色命名。由于对模型采用６种不同的学习次数（这里为：５００,１０００,２０００,３０００,５０００,１００００）以及４种不同比例（这里为：４：１,６：１,８：１,１０：１）字词模式和颜色模式的训练,其结果字词通道的信息加工比颜色通道的加工更快更强,并产生不同的干扰模式,其字词加工的次数越多,干扰越大,次数越少,干扰也越小。这很可能说明语言的熟练程度对干扰模式有着更大的影响。模型还体现了加工过程的连续性质。但这个模型难以区分不同的加工任务。     

Age-related trends of interference control in school-age children and young adults in the Stroop color-word test

In this cross-sectional study, differences in interference control, one component of executive function, were investigated among three age groups, 15 early childhood (7- to 8-yr.-olds), 25 middle childhood (9- to 12-yr.-olds), and 20 young adults (21- to 30-yr.-olds). Participants were administered a computer version of the Stroop color-word test with an oral response; correct responses, response time (RT), and the interference ratio were examined. The data indicated that (1) most of the participants showed no errors in word reading, color-naming, and incongruent color-naming tasks; (2) in word-reading and color-naming tasks, RT for 7- to 8-yr.-olds was longer than that for 9- to 12-yr.-olds, while RT of 9- to 12-yr.-olds and young adults were comparable; (3) in an incongruent color-naming task, RT for 7- to 8-yr.-olds was longer than RT for 9- to 12-yr.-olds, which was longer than RT for young adults; and (4) the interference ratio was higher in 7- to 8-yr.-olds than in 9- to 12-yr.-olds, which was higher than in young adults. These results suggested the difference in interference control between early and middle childhood reported on the go/no-go task and the stop-signal procedure would be observed in the Stroop color-word paradigm as well. The utility of this modified Stroop color-word test for those with intellectual and developmental disabilities was discussed.     

Age differences in Stroop interference: contributions of general slowing and task-specific deficits

This study examined the contributions of general slowing and task-specific deficits to age-related changes in Stroop interference. Nine hundred thirty-eight participants aged 20 to 89 years completed an abbreviated Stroop color-naming task and a subset of 281 participants also completed card-sorting, simple reaction time, and choice reaction time tasks. Age-related increases in incongruent color-naming latency and card-sorting perseverative errors were observed. Hierarchical regression analyses showed that the processing speed measures accounted for significant variance on both dependent measures, but that there was also a significant residual effect of age. An additional regression analysis showed that some of the variance in incongruent color-naming, after controlling for processing speed, was shared with the variance in perseverative errors. Overall, findings suggest that the age difference in Stroop interference is partially attributable to general slowing, but is also attributable to age-related changes in task-specific processes such as inhibitory control.