Language and orthography as irrelevant features in colour-word and picture-word stroop interference

Based on evidence that Chinese yields more interference than English, Biederman and Tsao (1979) have suggested that the processes involved in reading Chinese are more similar to those involved in colour naming than are the processes involved in reading English. In three experiments conducted to evaluate the empirical foundation for this hypothesis it was found that: (1) Chinese yielded less interference than English (and French) in between-subjects comparisons involving Chinese-English bilinguals and English monolinguals or English-French bilinguals; (2) Chinese print did not yield more interference than English print in within-subjects comparisons involving the orthogonal combination of print language (Chinese or English) and naming language (Chinese or English) among Chinese-English bilinguals; and (3) compared with syntactic category, both language and orthography were relatively impotent variables in the object naming version of the Stroop task.     

Interference control in children with reading difficulties

Two studies investigated whether the greater Stroop interference reported in children with reading difficulties compared to typical readers of the same age represents a generalized deficit in interference control or a consequence of their reading problems. In Study 1, a color-word Stroop task and a nonverbal task involving responses to locations associated with pictures were administered to 23 children with single word reading difficulties and 22 typically developing children matched for age and nonverbal ability. Children with reading difficulties showed disproportionate interference effects in the color-word Stroop but not the nonverbal task. In Study 2, groups of poor and typical readers completed a spatial Stroop task with printed input that did not require a verbal response and a nonverbal analogue. Both groups showed comparable interference in these two tasks. Thus, the reported problems in the color-word Stroop task in children with reading difficulties do not appear to entail general impairments in interference control.     

Aging and response inhibition: Normative data for the Victoria Stroop Test

Increased difficulty with response inhibition occurs with age, although there is some controversy as to whether increased interference on Stroop tasks reflects difficulties with response inhibition or simply reflects generalized cognitive slowing. The Victoria Stroop Test (VST) is a brief, easily administered, psychometrically sound version of Stroop's original task. Performance on the VST by adults across a wide age span was examined to determine the association between age and various measures of interference. In addition, normative data for the VST were calculated. Participants were 272 healthy, community-dwelling adults age 18 to 94. Age and speed were negatively correlated on all trials of the VST. Importantly, however, interference scores that were corrected for baseline slowing remained highly correlated with age. Similarly, age and error scores on the interference trial were positively correlated, indicating decreased accuracy with age. These findings suggest that increased interference on Stroop tasks with age is not accounted for by simple cognitive slowing and more likely reflects other cognitive changes, such as decreased response inhibition. The VST has a number of administrative and psychometric strengths, and the provision of normative data should enhance its potential for clinical and research applications.     

The contribution of orthography to spoken word production: Evidence from Mandarin Chinese

A recent debate in the language production literature concerns the influence of a word’s orthographic information on spoken word production and the extent to which this influence is modulated by task context. In the present study, Mandarin Chinese participants produced sets of words that shared orthography (O+P−), phonology (O−P+), or orthography and phonology (O+P+), or were unrelated (O−P−), in the context of a reading, associative naming, or picture naming task. Shared phonology yielded facilitation effects in all three tasks, but only in the reading task was this phonological effect modulated by shared orthography. Shared orthography by itself (O+P−) revealed inhibitory effects in reading, but not in associative naming or in picture naming. These results suggest that a word’s orthography information influences spoken word production only in tasks that rely heavily on orthographic information.     

The Stroop test: A developmental study in a French children sample aged 7 to 12 years

The Stroop test is a commonly used task in psychology to assess executive function and more specifically inhibition. International studies consistently show improved Stroop task performance with age, whereas available French normative data displays the opposite pattern, with poor clinical sensibility (Albaret & Migliore, 1999). To provide an alternative and useful Stroop test for children, we examined developmental data based on a well-known French protocol validated in adult (GREFEX study group, 2001). The three-standard conditions of the Stroop task (i.e. naming, reading and interference) were administered to 120 typically developing school children (7–12 years), while taking into account the effects of gender, parental educational level and intelligence (both crystallized and fluid intelligence, as measured by the Wechsler intelligence scale). The time to complete each condition (in seconds) was recorded, as well as the number of uncorrected and corrected errors. Results show a continuous increase of performance in “reading” and “naming” control conditions between 7 and 12 years, suggesting an improvement in the lexical access speed and the automation of decoding abilities during reading. Most importantly, a significant reduction of time Stroop effect with age was found (difference between interference and naming conditions), but no interaction with gender. Stroop performances are related to fluid intelligence once age is statistically controlled, but not to parental educational level. The developmental pattern found from the Stroop GREFEX version is consistent with international data and more broadly with executive function and inhibition development. These findings open the prospect of useful normative standardization of this task, with valuable clinical applications perspectives.     

Effectiveness of the Visual–Auditory Shadowing Method on Learning the Pronunciation of Kanji

This study investigates whether the visual–auditory (VA) shadowing method can better facilitate vocabulary learning for learners of Japanese as a second language (JSL) than the visual–visual (VV) shadowing method in K-8 immersion education. Learning vocabulary involves three aspects: meaning, orthography, and pronunciation. The Japanese language has complex orthography and pronunciation. Learners of Japanese need to learn three kinds of orthographic characters: ideographs (kanji) and two kinds of syllabic characters (hiragana and katakana). In addition, because the pronunciation of kanji can vary by context, learners must learn several pronunciations for a single kanji character. This study explores a reasonable way to learn pronunciations of kanji and compares VA shadowing (n = 48) and VV shadowing (n = 47) to investigate which condition better facilitates learning the pronunciation of Japanese ideographs. The analysis suggests that compared to the VV shadowing condition (p < .05), the VA shadowing condition is more effective for Level 3 learners but not for Level 2 or Level 1 learners.     

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.     

Absence of perceptual segmentation in image generation by normals

We used kanji characters (Chinese ideographic characters) and hiragana characters (Japanese phonographic characters) in the transfer‐appropriate processing paradigm to examine whether or not people without brain damage conduct perceptual segmentation while generating a visual mental image. Ninety‐six participants were divided into three study conditions: (a) seeing hiragana characters and generating a mental image of the corresponding kanji characters; (b) seeing the kanji characters; and (c) seeing the hiragana characters without generating the image of the kanji characters. Generating an image of a kanji character did not transfer at test to the decision as to whether the visually presented kanji character was vertically segmented or not, whereas it did transfer to a semantic decision as to whether the kanji character had a concrete or abstract meaning. Seeing a kanji character transferred to both decisions. Seeing hiragana characters without generating an image of the kanji characters transferred to neither decision. These results suggest that perceptual segmentation is not routinely conducted by normals in the process of image generation.     

The Guilty Knowledge Test and the modified Stroop task in detection of deception: an exploratory study

The current study tested whether a simple Stroop paradigm can be used to detect deceptive behavior. 40 university students (34 women), half of whom committed a mock crime, were administered a Guilty Knowledge Test and modified Stroop task to detect guilt or innocence. The Guilty Knowledge Test is a well-known psychophysiological detection method, which consists of multiple-choice questions about details of the crime while skin conductance is recorded. Subjects possessing guilty knowledge are expected to show enhanced differential responses to the relevant stimuli. The modified Stroop task required color-naming of colored words related to the mock crime or an irrelevant crime. Each version of the Stroop task was presented in story form. Subjects possessing guilty knowledge were expected to produce larger reaction times to the relevant version relative to the irrelevant version. The test correctly identified 100% of innocent participants and 78% of guilty participants. In contrast, Stroop interference. i.e., reaction times for irrelevant crime details subtracted from those for mock crime details, did not differentiate between the two groups, suggesting that the story form of the Stroop paradigm is not suitable for lie detection.     

Developmental differences in the use of task goals in a cued version of the stroop task

The ability of children (M= 8.8 years) and adults (M= 25.6 years) to maintain task goals was examined by comparing their performance on a cued version of the Stroop colour‐word task. The experimental task presented a cue on each trial that instructed the participant to either read aloud the forthcoming word or name the colour of the word's lettering. Participants were tested with each of two cue‐stimulus delays (1,000 and 5,000 ms). Analysis of error rates in the colour‐naming condition revealed that children experienced greater interference than adults at each of the cue‐stimulus delays. In an effort to separate the relative contributions of colour‐naming and word‐reading processes, additional analyses were performed based on the process dissociation procedure of Lindsay and Jacoby (1994) . While colour‐naming process estimates did not vary with age group or cue‐stimulus delay, word‐reading process estimates were found to vary with age group and cue‐stimulus delay. Specifically, adults were superior to children in the inhibition of irrelevant word information only during a long cue‐stimulus delay. Collectively, these findings indicate that children have difficulty maintaining task goals in order to suppress stronger, goal‐irrelevant responses.     

Visual span of detection and recognition of a kanji character embedded in a horizontal row of random hiragana characters

Two experiments were conducted to determine the visual span of detection and recognition of the kanji character embedded in a horizontal row of random hiragana characters. An independent variable was the visual complexity of the kanji characters: simple and complex. In Experiment 1, visual spans of detection were determined by a staircase method. Values of visual spans were more than 15 character spaces for the complex kanji characters, and ranged from 4 to 10 character spaces (mean 7.6) for the simple kanji characters. In Experiment 2, visual spans of recognition were determined by an ascending series of limits method. Values of visual spans ranged from 0 to 4 character spaces (mean 2.3) for the complex kanji characters and from 3 to 7 character spaces (mean 4.8) for the simple kanji characters. These results are discussed in relation to reading of Japanese kanji-kana mixed texts.     

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.     

Concurrent vocal interference: Its effects on kana and kanji

An experiment is reported in which Japanese subjects were asked to judge whether pairs of words written in kana or kanji were or were not related in meaning. It was found that concurrent vocal interference impaired the reading of kana but did not affect the reading of kanji. This was taken as evidence that concurrent vocal interference disrupts prelexical phonological coding in kana. It is argued that this result furthers our understanding of the effects of concurrent vocal interference on reading tasks.     

Training on integrated versus separated Stroop tasks: The progression of interference and facilitation

Two experiments examined the course of interference and facilitation in the Stroop (1935) task during training. Two versions of the task were compared: integrated (e.g., the word RED in the color green) and separated (e.g., green asterisks above the word RED). Stimuli were congruent (RED in red), incongruent (GREEN in red), or neutral (XXX in red). Over 5-day (Experiment 1) and 10-day (Experiment 2) training sessions, facilitation due to congruence was small, stable, and equivalent in both task versions. In contrast, interference declined sharply on the integrated task over Days 1-3, then slowed to parallel the gradual decline on the separated task. Finally, training on the color naming task did not affect a word reading task administered after training. These findings imply that (a) Stroop interference initially reflects two problems—overcoming integration and managing two conflicting information sources; (b) with practice, the larger integration problem is solved relatively quickly, rendering the integrated and separated tasks quite comparable thereafter; and (c) facilitation and interference in the Stroop task may be independent. These results challenge extant theories of the Stroop effect, which do not predict such effects.     

Components of Stroop-like interference in picture naming

The semantic interference effect observed in Stroop tasks and picture-word interference tasks might be due to the previous confounding of semantic similarity with task relevance (in the Stroop task) and with perceptual similarity (in the picture-word interference task). A picture-word variant of the Stroop task was devised in which the factors of task relevance and perceptual similarity were controlled. The distractor conditions allowed for the examination of four types of context effects. The results show that the overall Stroop-like interference effect can be decomposed into interference effects due to (1) a semantic relation between distractor and target, (2) the semantic relevance of the distractor word in the task at hand, (3) the presence of the distractor word in the response set, and (4) the mere presence of a word. Implications of these findings for the locus or loci of Stroop and picture-word interference effects are discussed. It is concluded that distractor words in Stroop-like naming tasks interfere mainly in the process of name retrieval.     

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.     

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.