Distractor Words Research Articles

Within-word serial order control: Adjacent mora exchange and serial position effects in repeated single-word production

An essential function of language processing is serial order control. Computational models of serial ordering and empirical data suggest that plan representations for ordered output of sound are governed by principles related to similarity. Among these principles, the temporal distance and edge principles at a within-word level have not been empirically demonstrated separately from other principles. Specifically, the temporal distance principle assumes that phonemes that are in the same word and thus temporally close are represented similarly. This principle would manifest as phoneme movement errors within the same word. However, such errors are rarely observed in English, likely reflecting stronger effects of syllabic constraints (i.e., phonemes in different positions within the syllable are distinctly represented). The edge principle assumes that the edges of a sequence are represented distinctly from other elements/positions. This principle has been repeatedly observed as a serial position effect in the context of phonological short-term memory. However, it has not been demonstrated in single-word production. This study provides direct evidence for the two abovementioned principles by using a speech-error induction technique to show the exchange of adjacent morae and serial position effects in Japanese four-mora words. Participants repeatedly produced a target word or nonword, immediately after hearing an aurally presented distractor word. The phonologically similar distractor words, which were created by exchanging adjacent morae in the target, induced adjacent-mora-exchange errors, demonstrating the within-word temporal distance principle. There was also a serial position effect in error rates, such that errors were mostly induced at the middle positions within a word. The results provide empirical evidence for the temporal distance and edge principles in within-word serial order control.

Semantic interference from distractor pictures in single-picture naming: evidence for competitive lexical selection

Picture-naming studies have demonstrated interference from semantic-categorically related distractor words, but not from corresponding distractor pictures, and the lack of generality of the interference effect has been argued to challenge theories viewing lexical selection in speech production as a competitive process. Here, we demonstrate that semantic interference from context pictures does become visible, if sufficient attention is allocated to them. We combined picture naming with a spatial-cuing procedure. When participants' attention was shifted to the distractor, semantically related distractor pictures interfered with the response, as compared with unrelated distractor pictures. This finding supports models conceiving lexical retrieval as competitive (Levelt, Roelofs, & Meyer, 1999) but is difficult to reconcile with the response exclusion hypothesis (Finkbeiner & Caramazza, 2006b) proposed as an alternative.

Written distractor words influence brain activity during overt picture naming

Language production requires multiple stages of processing (e.g., semantic retrieval, lexical selection), each of which may involve distinct brain regions. Distractor words can be combined with picture naming to examine factors that influence language production. Phonologically-related distractors have been found to speed picture naming (facilitation), while slower response times and decreased accuracy (interference) generally occur when a distractor is categorically related to the target image. However, other types of semantically-related distractors have been reported to produce a facilitative effect (e.g., associative, part-whole). The different pattern of results for different types of semantically-related distractors raises the question about how the nature of the semantic relation influences the effect of the distractor. To explore the nature of these semantic effects further, we used functional MRI to examine the influence of four types of written distractors on brain activation during overt picture naming. Distractors began with the same sound, were categorically-related, part of the object to be named, or were unrelated to the picture. Phonologically-related trials elicited greater activation than both semantic conditions (categorically-related and part-whole) in left insula and bilateral parietal cortex, regions that have been attributed to phonological aspects of production and encoding, respectively. Semantic conditions elicited greater activation than phonological trials in left posterior MTG, a region that has been linked to concept retrieval and semantic integration. Overall, the two semantic conditions did not differ substantially in their functional activation which suggests a similarity in the semantic demands and lexical competition across these two conditions.

Picture–Word Interference Reveals Inhibitory Effects of Syllable Frequency on Lexical Selection

While previous research has shown that high syllable frequency can facilitate speech production at the level of phonological/phonetic encoding, little is known about its influence on prephonological processes, specifically lexical selection. The current study used a picture-word interference (PWI) task to (a) shed light on the stages of lexical access where syllable frequency is relevant, and (b) inform as to whether lexical selection is accomplished via competition among activated word options. Participants named pictures whose names had high-frequency (HF) and low-frequency (LF) first syllables while ignoring phonologically related (same first syllable) or unrelated distractor words that were presented simultaneously. Word frequency was also manipulated, as half of the targets were HF words, and half were LF words. Results revealed inhibitory syllable frequency effects in all conditions, such that targets with HF first syllables were named more slowly than targets with LF first syllables. However, inhibitory syllable frequency effects were exacerbated in conditions thought to reflect heightened lexical competition, specifically in the presence of phonologically related distractors and for targets with low word frequency. These findings reveal novel evidence for first-syllable frequency effects on lexical selection and offer further support for models proposing delays at lexical selection due to activation of nontarget competitors.

Distinct Patterns of Brain Activity Characterise Lexical Activation and Competition in Spoken Word Production

According to a prominent theory of language production, concepts activate multiple associated words in memory, which enter into competition for selection. However, only a few electrophysiological studies have identified brain responses reflecting competition. Here, we report a magnetoencephalography study in which the activation of competing words was manipulated by presenting pictures (e.g., dog) with distractor words. The distractor and picture name were semantically related (cat), unrelated (pin), or identical (dog). Related distractors are stronger competitors to the picture name because they receive additional activation from the picture relative to other distractors. Picture naming times were longer with related than unrelated and identical distractors. Phase-locked and non-phase-locked activity were distinct but temporally related. Phase-locked activity in left temporal cortex, peaking at 400 ms, was larger on unrelated than related and identical trials, suggesting differential activation of alternative words by the picture-word stimuli. Non-phase-locked activity between roughly 350–650 ms (4–10 Hz) in left superior frontal gyrus was larger on related than unrelated and identical trials, suggesting differential resolution of the competition among the alternatives, as reflected in the naming times. These findings characterise distinct patterns of activity associated with lexical activation and competition, supporting the theory that words are selected by competition.

Locus of semantic interference in picture naming: Evidence from dual-task performance.

Disagreement exists regarding the functional locus of semantic interference of distractor words in picture naming. This effect is a cornerstone of modern psycholinguistic models of word production, which assume that it arises in lexical response-selection. However, recent evidence from studies of dual-task performance suggests a locus in perceptual or conceptual processing, prior to lexical response-selection. In these studies, participants manually responded to a tone and named a picture while ignoring a written distractor word. The stimulus onset asynchrony (SOA) between tone and picture-word stimulus was manipulated. Semantic interference in naming latencies was present at long tone pre-exposure SOAs, but reduced or absent at short SOAs. Under the prevailing structural or strategic response-selection bottleneck and central capacity sharing models of dual-task performance, the underadditivity of the effects of SOA and stimulus type suggests that semantic interference emerges before lexical response-selection. However, in more recent studies, additive effects of SOA and stimulus type were obtained. Here, we examined the discrepancy in results between these studies in 6 experiments in which we systematically manipulated various dimensions on which these earlier studies differed, including tasks, materials, stimulus types, and SOAs. In all our experiments, additive effects of SOA and stimulus type on naming latencies were obtained. These results strongly suggest that the semantic interference effect arises after perceptual and conceptual processing, during lexical response-selection or later. We discuss several theoretical alternatives with respect to their potential to account for the discrepancy between the present results and other studies showing underadditivity.

Friend or foe? Decoding the facilitative and disruptive effects of emotion on working memory in younger and older adults

A growing body of work on emotion-cognition interactions has revealed both facilitative and disruptive effects of emotion on working memory in younger adults. These differing effects may vary by the goal relevancy of emotion within a task. Additionally, it is possible that these emotional effects would be larger for older adults, considering findings of preserved emotional processing with age. To test these hypotheses, the current study examined the effects of emotional content and aging on working memory for target information in the presence of distraction. Thirty-six younger (ages 18–29) and 36 older adults (ages 65–87) completed a delayed-response working memory task. Participants viewed two target words intermixed with two distracter words, and then judged whether a subsequently presented probe word was one of the target words. The emotional content (valence and arousal) of targets and distracters was systematically manipulated. Results indicated that emotional targets facilitated working memory in both age groups. In contrast, emotional distracters disrupted performance. Negative distracters were particularly disruptive for older adults, but younger adults did not show an emotional interference effect. These findings help clarify discrepancies in the literature and contribute to the sparse research on emotional working memory in older adults.

The CRITICAL DIFFERENCE in models of speech production: A response to Roelofs and Piai

In our original article (Mahon, Garcea, & Navarrete, 2012), we replicated Dalrymple-Alford’s (1972) observation of semantic facilitation at zero SOA when participants name the ink color (e.g., ‘red’) of semantically related non-color words (e.g., ‘fire’) compared to semantically unrelated non-color word distractors (e.g., ‘lawn’; see also Glaser & Glaser, 1989). We replicated this classic finding to draw attention to the implications of this semantic facilitation effect, and semantic facilitation effects generally, for a model of word selection in speech production. The implication is straightforward: The theory of lexical selection by competition predicts that the distractor ‘fire’ should interferemorewith saying ‘red’ than thedistractor ‘lawn’. This (and other) observation(s) of semantic facilitation are incompatible with the theory of lexical selection by competition. WEAVERþþ (Roelofs, 1992, 2003) is the most developed model that implements lexical selection by competition, and as itmakes both qualitative and quantitative predictions, its ability to simulate response time effects has been taken as a litmus test of the viability of the hypothesis of lexical selection by competition. As Roelofs and Piai (2013) write of the original (i.e., Roelofs, 2003) WEAVERþþ simulations, “.facilitation of 41 msec or more was obtained at preexposure SOAs and no effect at zero SOA” (p. 1768). In other words, the previously published simulations of WEAVERþþ did not resemble, in relevant ways, the empirical data. On that

To what extent do we process the nondominant object in a morphed figure? Evidence from a picture–word interference task

To investigate to what extent response candidates are processed during visual object categorisation, two picture–word interference tasks were conducted in which the effects of different types of distractor words on object naming were examined. Distractor words were related to the dominant or the nondominant object in a morphed figure. We assume both the dominant and nondominant object to be response candidates during response competition. The distractor words were identical (dog-dog), semantically related (cow-dog), or unrelated (spoon-dog) to the dominant or nondominant object. It was found that in relation to the dominant object in a morphed figure identical distractors facilitated naming, whereas semantically related distractors caused interference indicating a general semantic interference effect. Moreover, in relation to the nondominant object identical words interfered with naming, whereas semantically related words only interfered with naming when they were response set members. Therefore, identical words in general influenced the activation of the nondominant response candidate, whereas semantically related words only did so under restricted conditions. The latter will be discussed in terms of short-term memory load. Overall, we conclude that the nondominant response candidate is processed up to the perceptual level.

About the locus of the distractor frequency effect: Evidence from the production of clitic pronouns

In this study, we report results from two experiments in which pictures were shown with superimposed distractors that varied along two dimensions: frequency (high vs. low) and semantic relation with respect to the picture (related vs. unrelated). In one condition of Experiment 1, participants named pictures with a noun utterance; in the other condition of Experiment 1 and in Experiment 2 participants named pictures with a pronominal utterance. Low frequency distractor words produced greater interference with respect to high frequency words in noun production, but not in pronoun production. Critically, a semantic interference effect, greater interference in the semantically related than unrelated condition, was reported in both experiments, suggesting that distractor words were equally processed in both noun and pronoun conditions. These results are discussed in the context of current models of picture–word interference.

Resolving semantic interference during word production requires central attention.

The semantic picture-word interference task has been used to diagnose how speakers resolve competition while selecting words for production. The attentional demands of this resolution process were assessed in 2 dual-task experiments (tone classification followed by picture naming). In Experiment 1, when pictures and distractor words were presented simultaneously, semantic interference was not observed when tasks maximally overlapped. This replicates a key finding from the literature that suggested that semantic picture-word interference does not require capacity-limited central attentional resources and occurs prior to lexical selection, an interpretation that runs counter to the claims of all major theories of word production. In another Experiment 1 condition, when distractors were presented 250 ms after pictures, interference emerged when tasks maximally overlapped. Together, these findings support an account in which interference resolution and lexical selection both require central resources, but the activation of lexical representations from written words does not. Subsequent analysis revealed that discrepant results obtained in previous replication attempts may be attributable to differences in phonological (ir)regularity between languages. In Experiment 2, degree of semantic interference was manipulated using the cumulative semantic interference paradigm. Interference was observed regardless of task overlap, confirming that lexical selection requires central resources. Together, these findings indicate that a lexical selection locus of semantic picture-word interference-and models of word production that assume such a locus-may be retained.

Semantic interference in language production is due to graded similarity, not response relevance

There is an ongoing debate on the question whether semantic interference effects in language production reflect competitive processes at the level of lexical selection or whether they reflect a post-lexical bottleneck, occupied in particular by response-relevant distractor words. To disentangle item-inherent categorical relatedness and task-related response relevance effects, we combined the picture–word interference task with the conditional naming paradigm in an orthogonal design, varying categorical relatedness and task-related response relevance independent of each other. Participants were instructed to name only objects that are typically seen in or on the water (e.g. canoe) and refrain from naming objects that are typically located outside the water (e.g. bike), and vice versa. Semantic relatedness and the response relevance of superimposed distractor words were manipulated orthogonally. The pattern of results revealed no evidence for response relevance as a major source of semantic interference effects in the PWI paradigm. In contrast, our data demonstrate that semantic similarity beyond categorical relations is critical for interference effects to be observed. Together, these findings provide support for the assumption that lexical selection is competitive and that semantic interference effects in the PWI paradigm reflect this competition.

Relative speed of processing affects interference in Stroop and picture–word interference paradigms: evidence from the distractor frequency effect

The Stroop and picture–word interference (PWI) paradigms play a pivotal role in theorising about cognitive processes in general, and language production in particular. A common assumption is that the same mechanisms underlie performance in these two paradigms. Despite this assumption there exist empirical discrepancies. Here we focused on providing a unifying account for the contrasting effects of distractor word frequency in the two paradigms. In four experiments, we addressed whether the contrast is due to inherent design differences between the two paradigms (i.e., grammatical class, stimulus display and relative speed of processing). The results showed that the distractor frequency effect is contingent upon the overall naming latencies in the paradigm, suggesting that the speed of processing target colours and pictures relative to distractor words affects performance in the two tasks. The implications of these results for various models of language production are discussed.

What does the articulatory output buffer know about alternative picture names? Evidence against the response-exclusion hypothesis

When participants name pictures in the presence of a distractor word, a semantic relation between distractor word and picture name interferes with the naming response. Some models take this to reflect a lexical-competition process, while other models assume it to result from a postlexical response-exclusion mechanism. According to the latter view, the distractor word has privileged access to an articulatory output buffer and has to be purged from it before the picture name can be produced. This buffer is assumed to have access to information that is relevant within a given task such as gross semantic category information. Any (semantic) similarity between the picture name and the distractor word then should render removal of the distractor more difficult and thus prolong naming latencies. However, more fine-grained semantic information is not accessible to the articulatory output buffer and, thus, should not affect naming performance. We tested this assumption by comparing the effect of two semantic distractor conditions keeping the semantic relation between distractor words and the to-be-produced (basic-level) picture names constant, while manipulating only the relation between the distractor and the pictures' subordinate-level name. Contrary to the predictions of the response-exclusion hypothesis, this manipulation determined whether or not semantic interference was obtained.

Time course analysis of the effects of distractor frequency and categorical relatedness in picture naming: An evaluation of the response exclusion account

The response exclusion account (REA), advanced by Mahon and colleagues, localises the distractor frequency effect and the semantic interference effect in picture naming at the level of the response output buffer. We derive four predictions from the REA: (1) the size of the distractor frequency effect should be identical to the frequency effect obtained when distractor words are read aloud, (2) the distractor frequency effect should not change in size when stimulus-onset asynchrony (SOA) is manipulated, (3) the interference effect induced by a distractor word (as measured from a nonword control distractor) should increase in size with increasing SOA, and (4) the word frequency effect and the semantic interference effect should be additive. The results of the picture-naming task in Experiment 1 and the word-reading task in Experiment 2 refute all four predictions. We discuss a tentative account of the findings obtained within a traditional selection-by-competition model in which both context effects are localised at the level of lexical selection.

Explaining semantic facilitation and interference effects in the picture–word interference task—A rejoinder to Navarrete and Mahon (2013)

In our original article, we presented a picture–word interference experiment in which pictures had to be named with basic level names, although their naming preference was at the subordinate level (e.g., picture: rose, response: flower). We observed semantic interference for distractor words denoting the subordinate name of the picture, but no effect for distractor words denoting another subordinate name corresponding to the same basic level. We argued that this pattern is inconsistent with the assumption that semantic interference effects in picture–word interference tasks are caused by a post-lexical response-exclusion mechanism which operates over coarse semantic properties of distractor words, but that lexical competition models can account for these results. In their commentary on our article, Navarrete and Mahon come to the opposite conclusion. Here we are addressing the principal objections raised by Navarrete and Mahon, regarding the interpretation of our results. We elaborate on our view that lexical competition models can account for our data and agree that a response-exclusion mechanism, which is part of a general monitoring system and operates over fine-grained semantic information, would be compatible with our data.

Response exclusion in word–word tasks: A comment on Roelofs, Piai and Schriefers

Roelofs, Piai, and Schriefers discuss a series of results obtained from various word reading tasks in the context of word and picture distractors. They argue that these results support WEAVER++, a computational model of word production that assumes a competitive lexical selection mechanism, and challenge the response exclusion hypothesis, a model that assumes a non-competitive lexical selection mechanism. At odds with this claim, I argue here that these data do not pose problems for the response exclusion hypothesis. I also discuss new avenues of research to advance the debate on the mechanism of lexical selection.

Selection by competition in word production: Rejoinder to Janssen (2013)

Roelofs, Piai, and Schriefers argue that several findings on the effect of distractor words and pictures in producing words support a selection-by-competition account and challenge a non-competitive response-exclusion account. Janssen argues that the findings do not challenge response exclusion, and he conjectures that both competitive and non-competitive mechanisms underlie word selection. Here, we maintain that the findings do challenge the response-exclusion account and support the assumption of a single competitive mechanism underlying word selection.

Selective and nonselective inhibition of competitors in picture naming

The present study examined the relation between nonselective inhibition and selective inhibition in picture naming performance. Nonselective inhibition refers to the ability to suppress any unwanted response, whereas selective inhibition refers to the ability to suppress specific competing responses. The degree of competition in picture naming was manipulated by presenting targets along with distractor words that could be semantically related (e.g., a picture of a dog combined with the word cat) or unrelated (tree) to the picture name. The mean naming response time (RT) was longer in the related than in the unrelated condition, reflecting semantic interference. Delta plot analyses showed that participants with small mean semantic interference effects employed selective inhibition more effectively than did participants with larger semantic interference effects. The participants were also tested on the stop-signal task, which taps nonselective inhibition. Their performance on this task was correlated with their mean naming RT but, importantly, not with the selective inhibition indexed by the delta plot analyses and the magnitude of the semantic interference effect. These results indicate that nonselective inhibition ability and selective inhibition of competitors in picture naming are separable to some extent.

Roles of Semantic Similarity and Category Size on Semantic Effect in Picture-Word Interference Paradigm

One of the workhorses in studying spoken word production is the picture-word interference paradigm (PWI). In this paradigm, speakers are instructed to ignore superimposed written distractor words while fulfilling the picture-naming task. An essential finding in picture - word interference paradigm is that people spend more time in naming pictures when distractor word is of the same category as the picture naming (semantic related word) than when the distractor is unrelated. That effect is often referred to as semantic interference effect (SIE). A reversed finding is that pictures naming latency is shorter in condition of related words than in condition of unrelated words. That effect is referred to as semantic facilitation At present, there are several theories about the nature and level of effects in picture - word interference paradigm. Lexical selection by competition hypothesis assumes that SIE is the result of competition between the representations of related distractor word and the target word and then arises at lexical level. Conceptual selection model interprets the effects as the result of competition between the representations of distractor conception and the target conception. As a result, effect should arise at level. Response selection account proposes that there is a single-channel output buffer in word production and the non –target response would occupy the buffer earlier than the target. It will take some time to exclude the non-target response from the buffer and induces SIE. So SIE arises at the post-lexical stage in word production. Each account has its experimental evidence and each has its difficulty in explaining some phenomenon. In the present study, 2 experiments were conducted to investigate the universality of current theories and to explore the roles of similarity and category size on effect in PWI. In Experiment 1, subjects were asked to name pictures accompanied by words with high similarity or words with low similarity at either basic level or at category level. Results showed a shorter picture - naming latency in condition of high similarity distractor words than in condition of low similarity words, leading to significant similarity effect. Nevertheless, similarity effect occurred in basic - level naming rather than in category - level naming and the effect was stronger for low familiar pictures than for high familiar ones. Experiment 1 also showed that latency of category - level naming was shorter than that of basic-level naming and high familiar pictures were named faster than low familiar ones. Combining previous studies, these results suggested that the intensity of relationship between pictures and words would affect the direction of effect in the PWI. Semantic facilitation effect will be foundwhen there is strong relationship between pictures and words. Otherwise, interference will be found. In Experiment 2, subjects were asked to name pictures accompanied by related words or by unrelated words. Thirty pictures from large size of category and another thirty pictures from small size of category were chosen for this experiment. Results showed that related words had rather different influences on pictures naming in different condition. They would promote pictures category-level naming, thus giving rise to facilitation effect. However, they would interference pictures basic-level naming, thus causing interference effect. Category size had a prominent influence on these effects. Semantic interference effect would be stronger for large size of category pictures in basic-level naming and facilitation effect also would be stronger for big size of category pictures in category-level naming. Combining previous studies, the experiment suggested that the range of relationship between pictures and words affects the size of effect. When there is wide range of relationship, the effect will became stronger. Otherwise, the effect will be weaker. Single current theory of effect couldn’t give a proper explanation for the findings in this study. Results in this study were discussed with reference to the equilibrium between conceptual priming and lexical competition. If the conceptual priming overweight the lexical competition, facilitation effect would be found, otherwise interference would be found.