Phonological neighbourhood spread facilitates lexical decisions

In visual word recognition, words with many phonological neighbours are processed more rapidly than are those with few neighbours. The research reported here tested whether the distribution of phonological neighbours across phoneme positions influences lexical decisions. The results indicate that participants responded more rapidly to words where all phoneme positions can be changed to form a neighbour than they did to those where only a limited number of phoneme positions can be changed to form a neighbour. It is argued that this distribution effect arises because of differences between the two groups of words in how they overlap with their neighbours.     

Context modulates hemispheric asymmetries in the resolution of lexical ambiguity

Previous studies have reported a hemispheric asymmetry in processing dominant (e.g., paper) and subordinate (e.g., farmer) associations of ambiguous words (e.g., pen). The majority of these studies, however, applied randomly ordered presentation and collected right-hand responses only. Generating responses solely with the right hand and the randomly ordered presentation of association type might have affected natural hemispheric expertise. We explored the putative relationships between responding hand and experimental design manipulations in processing lexical ambiguity. Ambiguous target words were laterally presented following word pairs that could be associated to the dominant or subordinate meaning of the target word. We manipulated the responding hand and the experimental context by presenting the semantic associations in a random (Experiment 1) and a blocked ordered presentation (Experiment 2). The results of Experiment 2 supported the right hemisphere expertise hypothesis, whereas the results of Experiment 1 can be best explained by the direct access model where stimuli are processed by the hemisphere receiving them first, without relying on hemispheric expertise. We conclude that without manipulating the responding hand, there is a risk of misinterpreting direct access results as evidence for hemispheric expertise. Moreover, we suggest that a blocked ordered presentation might encourage participants to use the expert hemisphere for the blocked factor. A new theoretical framework is presented to explain the findings.     

Influence of hedonic tone on lexical decisions

A lexical decision task was used to investigate the effect of a word’s hedonic tone on decision time. Thirty words, varying in degrees of pleasantness, were randomly presented with 30 nonwords, half of which were pronounceable and half not. It was demonstrated that decision times for the pleasant words were significantly faster than for the unpleasant words. The two types of nonwords were also found to differ: Decision times for the pronounceable nonwords were significantly slower than for the nonpronounceables. Results are discussed in the light of previous work in both memory and perception. The utility of the lexical decision task for relevant future research is also considered. Part of the work reported in this paper was supported by North East London Polytechnic as partial fulfillment of the requirements for a higher degree (C.N.A.A.).     

Auditory lexical decisions in children with specific language impairment

This study examined spoken‐word recognition in children with specific language impairment (SLI) and normally developing children matched separately for age and receptive language ability. Accuracy and reaction times on an auditory lexical decision task were compared. Children with SLI were less accurate than both control groups. Two subgroups of children with SLI, distinguished by performance accuracy only, were identified. One group performed within normal limits, while a second group was significantly less accurate. Children with SLI were not slower than the age‐matched controls or language‐matched controls. Further, the time taken to detect an auditory signal, make a decision, or initiate a verbal response did not account for the differences between the groups. The findings are interpreted as evidence for language‐appropriate processing skills acting upon imprecise or underspecified stored representations.     

Repetition proportion biases masked priming of lexical decisions

Although subjects have little or no awareness of masked primes, Bodner and Masson (2001) found that priming of lexical decisions is often enhanced when masked repetition primes occur on a high proportion of trials. We used baseline prime conditions to specify the locus of this repetition proportion (RP) effect. In Experiments 1A and 1B, a .8-RP group showed more priming than did a .2-RP group, and this RP effect was due to both (1) increased facilitation from repetition primes and (2) increased interference from unrelated primes. In Experiment 2, we used the baseline condition to show that subjects are sensitive to RP rather than to the proportion of unrelated primes. Direct comparisons of a given prime condition (repetition, unrelated) across RP conditions were more stable than were comparisons relative to the baseline condition. The increased costs and benefits of repetition priming when RP is higher implicate a context-sensitive mechanism that constrains accounts of masked priming.     

BALDEY: A database of auditory lexical decisions

In an auditory lexical decision experiment, 5541 spoken content words and pseudowords were presented to 20 native speakers of Dutch. The words vary in phonological make-up and in number of syllables and stress pattern, and are further representative of the native Dutch vocabulary in that most are morphologically complex, comprising two stems or one stem plus derivational and inflectional suffixes, with inflections representing both regular and irregular paradigms; the pseudowords were matched in these respects to the real words. The BALDEY (“biggest auditory lexical decision experiment yet”) data file includes response times and accuracy rates, with for each item morphological information plus phonological and acoustic information derived from automatic phonemic segmentation of the stimuli. Two initial analyses illustrate how this data set can be used. First, we discuss several measures of the point at which a word has no further neighbours and compare the degree to which each measure predicts our lexical decision response outcomes. Second, we investigate how well four different measures of frequency of occurrence (from written corpora, spoken corpora, subtitles, and frequency ratings by 75 participants) predict the same outcomes. These analyses motivate general conclusions about the auditory lexical decision task. The (publicly available) BALDEY database lends itself to many further analyses.     

Right hemisphere contribution to lexical access in an aphasic with deep dyslexia

Three hemifield tachistoscopic studies of a right-handed patient with acquired Broca's aphasia and deep dyslexia, but with intact visual fields, are presented to support the hypothesis of right hemisphere (RH) participation in deep dyslexic reading. A systematic comparison of this deep dyslexic with the disconnected RHs of two patients with complete cerebral commissurotomy disclosed a similar, but not identical, pattern of abilities. The results demonstrate partial reliance on the RH for accessing the meaning of single words, but not for phonological encoding in this patient.     

Hemispheric processing characteristics for lexical decisions in adults with reading disorders

The present study measured unilateral tachistoscopic vocal reaction times and error responses of reading-disordered and normally reading adults to single words and nonwords in a series of lexical decision tasks at two linguistic levels (concrete and abstract words). Analysis of variance on reaction times indicated that main effects of stimulus type, visual field, and the interaction of these variables were not significant for the reading-disordered group, but visual field and an interaction of visual field and stimulus type were for the normally reading adults. Error rate showed a significant interaction of stimulus x visual field for the reading-disordered group but not for the normal reading group. Post hoc tests showed significant differences in error rates between visual fields for concrete lexicon but not for abstract or nonsense lexicon for the reading-disordered group. These findings suggest a deficit in interhemispheric lexical transfer occurs for reading-disordered samples and suggest use of a callosal relay model wherein the left hemisphere is allocated responsibility for performing central operations underlying lexical decisions by adults with reading disorders.     

Part-set cueing and lexical decisions: Testing an inhibitory account

Providing some elements of a studied set during testing (part-set cues) can impair memory for the remaining elements (noncues)—a counterintuitive effect that has recently been attributed to inhibition of noncues. To test for such inhibition using a lexical decision task, we manipulated semantic and episodic relationships, such that cues and noncues were related only semantically, only episodically, or both semantically and episodically. Results showed that part-set cueing evoked inhibition, slowing lexical decisions for noncues that were related to cues both semantically and episodically, consistent with previous results involving the retrieval practice paradigm. However, either type of relationship alone was insufficient to slow decisions, despite previous evidence of impaired memory in similar conditions when tested with other measures such as free recall. The latter results raise questions regarding the extent to which inhibition can account for cueing-induced impairment when cues and noncues are related only semantically or only episodically.     

Semantic, phonological, and mediated priming in reading and lexical decisions

Four experiments were conducted to investigate whether semantic activation of a concept spreads to phonologically and graphemically related concepts. In lexical decision or self-paced reading tasks, subjects responded to pairs of words that were semantically related (e.g., light-lamp), that rhymed (e.g., lamp-damp), or that combined both of these relations through a mediating word (e.g., light-damp). In one version of each task, test lists contained word-word pairs (e.g., light-lamp) as well as nonword-word (e.g., pown-table) and word-nonword pairs (e.g., month-poad); in another version, test lists contained only word-word pairs. The lexical decision and self-paced reading tasks were facilitated by semantic and rhyming relations regardless of the presence or absence of nonwords on the test lists. The effect of the mediated relation, however, depended on the presence of nonwords among the stimuli. When only words were included, there was no effect of the mediated relation, but when nonwords were included, lexical decision and self-paced reading responses were inhibited by the mediated relation. These inhibitory effects are attributed to processes occurring after lexical access, and the relative advantages of the self-paced reading task are discussed.     

Aspectual asymmetries in the mental representation of events: Role of lexical and grammatical aspect

Temporal information is important in the construction of situation models, and many languages make use of perfective and imperfective aspect markers to distinguish between completed situations (e.g., He made a cake) and ongoing situations (e.g., He is making a cake). Previous studies in which the effect of grammatical aspect has been examined have shown that perfective sentences are often processed more quickly than imperfective ones (e.g., Chan, Yap, Shirai, & Matthews, 2004; Madden & Zwaan, 2003; Yap et al., 2004; Yap et al., 2006). However, these studies used only accomplishment verbs (i.e., verbs with an inherent endpoint, such as bake a cake). The present study on the processing of Cantonese includes activity verbs (i.e., durative verbs with no inherent endpoint, such as play the piano), and the results indicate a strong interaction between lexical aspect (i.e., verb type) and grammatical aspect. That is, perfective sentences were processed more quickly with accomplishment verbs, consistent with previous findings, but imperfective sentences were processed more quickly with activity verbs. We suggest that these different aspectual asymmetries emerge as a result of the inherent associations between accomplishment verbs and the bounded features of perfective aspect and between activity verbs and the unbounded features of imperfective aspect. The sentence stimuli from this study may be downloaded from mc.psychonomic-journals.org/content/supplemental.     

Sentence frame contexts and lexical decisions: Sentence-acceptability and word-relatedness effects

Many studies have explored the effects of single-word contexts on visual word recognition, and several models have been proposed to account for the results obtained. However, relatively little is known about the effects of sentence contexts. In the experiment reported, the contexts consisted of sentences with the final word deleted, and subjects made word-nonword (lexical) decisions on target strings of letters. Norms were collected to determine the most common completion for each sentence frame. The experiment yielded three main findings: (1) Lexical decisions were fastest for words that were the most common completions; (2) among words not given as completions in the norming procedure, decisions were faster for words related to the most common completions than for words unrelated to the most common completions; t3t also among words that were not produced as completions, decisions were faster for words that formed acceptable completions than for words that did not. These relatedness and sentence-acceptability effects were independent, so that the relatedness effect held even when the target words formed anomalous sentence completions. In order to account for these results, a model combining two types of processes is required. In the model described, schematic knowledge (Rumelhart & Ortony, 1977) operates upon a semantic network to activate particular nodes, and this activation spreads to related concepts as in the Collins and Loftus (1975) model.     

Effects of constraint and validity of sentence contexts on lexical decisions

Recent models of sentence context effects predict that the pattern of facilitation and inhibition of response to sentence completions should be influenced by the experiment-wide contextual “environment.” In the present experiments, this environment was manipulated in several ways, including the degree to which contexts constrained possible completions, the probability of predictable completions’ being presented, and the probability of congruous completions’ being presented. In Experiment 1, decreasing the proportion of congruent test words had no effect on either the facilitation for highly likely words or the inhibition for incongruent words; increasing the proportion of predictable words produced no increase in facilitation for these words, but did increase the inhibition for incongruous words. In Experiment 2, contexts with very high or very low degrees of constraint produced equivalent results when predictability was uniformly low: no facilitation for unlikely but congruent words, and inhibition for incongruent words. In general, the patterns of change in facilitation and inhibition caused by changes in the contextual environment were more consistent with the modified two-process model (Stanovich & West, 1983) than with the verification model (Becker, 1982). But the limited range of influence suggests that, under conditions approximating normal reading, little use is made of such “metacontextual” information.     

Attentional resource demands of visual word recognition in naming and lexical decisions.

Attentional demands of lexical access were assessed with dual-task methodology. Subjects performed an auditory probe task alone (single-task) or combined (dual-task) with either a lexical decision or a naming task. In Experiment 1, probe performance showed a decrement from single- to dual-task conditions during recognition of words in both lexical decision and naming tasks. In addition, decrements in probe performance were larger during processing of low-frequency compared with high-frequency words in both of the word recognition tasks. Experiment 2 showed that the time course of frequency-sensitive demands was similar across lexical decision and naming tasks and that attention is required early in the word recognition sequence. The results support the assumption that lexical access is both frequency sensitive and attention demanding.     

Structural influences on the resolution of lexical ambiguity: an analysis of hemispheric asymmetries

Structural influences on lexical ambiguity resolution in the two cerebral hemispheres was investigated using a divided visual field procedure. Participants were presented with auditory Wh- sentences containing an ambiguous word, where the grammatical role of the word was apparent only at a sentence-final verb (e.g., "Which BANK did the woman see?"). Following a sentence, either immediately or after 600 ms, a target word was presented in either the right or left visual field. Targets were related to the ambiguous word's dominant meaning (MONEY), the subordinate meaning (RIVER), or were unrelated. With left visual field presentation, priming occurred for both dominant- and subordinate-related targets at a 0 ms delay, but only for dominant-related targets at 600 ms. With left visual field presentation, priming occurred for subordinate-related targets only at both delays. The results suggest that grammatical assignment triggers the selection of meaning in the left hemisphere, whereas processing in the right hemisphere operates independently of structural analyses.     

Hemispheric asymmetry in lexical decisions: the effects of grammatical class and imageability

It has been suggested that neural systems for lexical processing of nouns and verbs are anatomically distinct. The aim of the present study was to investigate if brain asymmetry for the processing of these two grammatical classes is also different. Neurologically intact adults performed a lateralized lexical decision task with grammatically unambiguous words of high, medium, and low degrees of imagery. For error scores a right visual field (RVF) advantage and an overall effect of imageability were obtained. For latency scores grammatical class and imageability modified visual field differences: in the noun class a RVF advantage was obtained only for low imagery nouns, while for the verbs the RVF advantage was present for both medium and low imagery verbs. These results suggest that the participation of right hemisphere neural systems in the processing of verbs is more limited than in the processing of nouns.     

The facilitation of lexical decisions by a prime occurring after the target

Three experiments are reported that investigate priming effects in a lexical decision task. when the prime was presented after the target. In Experiment 1, the lexical decision target was presented for 50 msec, followed 80 msec later by the prime. No significant facilitation of responses was observed in the related prime condition. In Experiment 2, the target was presented for 30 msec, followed 35 msec later by the prime. Targets followed by related primes were responded to significantly faster than targets with unrelated primes. Experiment 3 replicated the result of Experiment 2. The data are interpreted as supporting parallel processing of the prime and target in semantic priming experiments. The theoretical implications of the “backward” priming effect are discussed.     

Contextual validity and the effects of low-constraint sentence contexts on lexical decisions

Subjects made lexical decisions after reading either (a) low-constraint sentence contexts that did not predict the identity or meaning of congruous targets (e.g. “Mary went to her room to look at her XXXX”), or (b) control contexts that were randomly ordered lists of words. The crucial variable was the validity of the contextual information. When the sentence contexts were incongrous with the word targets as often as they were congruous (the “less-valid environment”), the congruous contexts had a slight inhibitory effect on decision latency relative to the baseline condition. In contrast, when the contexts were always congruous with the word targets (“valid environment”), they had a large facilitatory effect on decision latency. These results suggest that (a) the effects of congruous contexts can depend on the validity of the contexts across the entire experimental session, and (b) contextual facilitation may be due in part to sentence level processes.     

Attentional asymmetries during concurrent bimanual performance

An asymmetry of attention was observed when subjects attempted to perform concurrent, relatively independent tasks with the two hands: right-handed subjects performed very much better on a dual task which required them to follow the beat of a metronome with the left while tapping as quickly as they could with the right than with the converse arrangement. It is suggested that attentional strategies which have evolved to allow guidance of interdependent skilled bimanual activities are also used when subjects attempt to perform relatively independent concurrent bimanual movements, which are not observed in the naturally occurring motor repertoire. Thus, interactions between hand, hand preference and nature of task are an important factor in dual task performance.     

Measuring lexical access during sentence processing

The results from “on-line” investigations of sentence comprehension are often difficult to interpret since it is not always apparent what component processes are reflected in the response measure. The results of two experiments reported here indicate that response latencies from phoneme-triggered lexical decision (PTLD) reflect the time needed for lexical access during sentence processing. Listeners were presented with sentences and were asked to make a word/nonword judgment for items beginning with a particular word-initial target phoneme. Speed of lexical access was manipulated by varying the semantic predictability of the target-bearing word. WORD judgments were faster for words that were preceded by semantically related verbs than were WORD judgments for words that were preceded by neutral verbs. The present results are consistent with other studies showing semantic facilitation of lexical access during the processing of fluent speech. It is argued that the phoneme-triggered lexical-decision task is a more suitable measure of lexical access during sentence processing than phoneme monitoring (Foss, 1969) or word monitoring (Marslen-Wilson & Tyler, 19751. In addition, it is pointed out that the phoneme-triggered lexical-decision task lends itself to modifications which should enable investigators to study various aspects of on-line sentence processing.