Semantic Competition as The Basis of Stroop Interference: Evidence From Color-Word Matching Tasks

Abstract

A color-word matching task was used to investigate the basis of Stroop interference. Subjects were shown a pair of stimuli: an ink color (e.g., a red bar) and a colored word (e.g., RED printed in red or blue) and decided whether the two items had the same meaning (meaning decisions) or whether they had the same surface color (visual decisions). In Experiment 1, the two stimuli were shown simultaneously, and conflicting visual information of the word (e.g., RED printed in blue, against a red bar) led to interference in meaning decisions, whereas conflicting verbal information (e.g., BLUE printed in red, against a red bar) produced no interference in visual decisions. In Experiment 2, as an increasing time interval was imposed between presentation of the color bar and the colored word, interference in meaning decisions diminished, whereas interference in visual decisions was established. These results suggest that semantic competition, not response competition, is the major source of Stroop and Stroop-like interference.One of the most popular tasks for studying the relationship of word reading, object naming, and selective attention is the Stroop colorword task (Stroop, 1935). In the Stroop task, subjects are asked to name the color of a color patch or the color of a colored word. Relative to naming a color patch, subjects often show a large delay in naming the color in which a color word is printed (e.g., blue in red ink). The Stroop effect is highly robust and has been demonstrated for a variety of stimulus materials and experimental tasks (see MacLeod, 1991, for a comprehensive review). The mechanism underlying the Stroop effect is, however, far from clear, despite more than six decades of intensive investigation.There are two classic accounts of the Stroop phenomenon (MacLeod, 1991). The relative-speed-of-processing hypothesis (e.g., Morton & Chambers, 1973;Posner & Snyder, 1975) attributes Stroop interference to the fact that word reading is faster than color naming (e.g., Cattell, 1886;Theios & Amrhein, 1989). According to this account, when two potential responses, one from reading a word and one from naming an ink color, compete to be the response to be selected for output, the consequence is a delay in response production, especially when the response from the more rapid process is the one to be ignored. Note that the relative-speed-of-processing hypothesis places the locus of interference at the stage of response output.The second account, the automaticity hypothesis (e.g., LaBerge & Samuels, 1974;Shiffrin & Schneider, 1977), attributes Stroop interference to the fact that word reading is more automatic than color naming (e.g., Cattell, 1886;Posner & Snyder, 1975

Concurrent working memory load can reduce distraction

“…Experiment 1A. In the meaning-comparison Stroop task, participants decided whether the color of a patch was the same as the meaning of a colored word while retaining in WM seven letters that were randomly renewed in each trial (5). That is, participants had to use verbal mechanisms to process the meaning of the target word in the Stroop task and to retain the letters in WM.…”

“…Stroop and other researchers (2)(3)(4) explained this interference with the automaticity hypothesis: Word reading is more automatic than color naming. According to this account, the more arduous, attentiondemanding process of color naming is hampered by the more automatic process of word reading (5). However, contrary to predictions from the word automaticity account, Stroop interference can be observed from color distractors in revised versions of the task (5,6).…”

“…According to this account, the more arduous, attentiondemanding process of color naming is hampered by the more automatic process of word reading (5). However, contrary to predictions from the word automaticity account, Stroop interference can be observed from color distractors in revised versions of the task (5,6). Thus, a more general explanation of the Stroop effect simply focuses on the inability to ignore distractor information, which may vary in salience depending on the task.…”

When in Doubt, Do it Both Ways: Brain Evidence of the Simultaneous Activation of Conflicting Motor Responses in a Spatial Stroop Task

“…Other investigators, however, have obtained data inconsistent with this hypothesis (e.g., Henik, Ro, Merrill, Rafal, & Safadi, 1999), and alternative explanations have been proposed such as attention modulation (e.g., Besner & Stolz, 1999;Walley, McLeod, & Khan, 1997), semantic interference effects (e.g., Luo, 1999), or a combination of several causes (Sharma & McKenna, 1998;O'Leary & Barber, 1993). However, most investigators appear to agree that the continuous flow of information between the stimulus evaluation and the response system, and the resulting response competition, plays at least a partial role in the RT delay associated with responding to incongruent stimuli (e.g., Kornblum, Stevens, Whipple, & Requin, 1999;Lu & Proctor, 1995;MacLeod, 1991;Cohen, Dunbar, & McClelland, 1990).…”

Role of attention and translation in conflict resolution: Implications for Stroop matching task interference.

“…He concluded that interference was attributable to conflict occurring at the semantic-level representation. Importantly, the SOAs adopted by Luo (1999) were long, and thus he could not study the gradual implementation of controlled mechanisms necessary to execute the tasks.…”