Visual Lexical Decision Task Research Articles

The role of feedback from phonology to orthography in orthographic learning: an extension of item‐based accounts

Skilled readers were trained to recognise either the oral (n=44) or visual form (n=40) of a set of 32 novel words (oral and visual instantiation, respectively). Training involved learning the ‘meanings’ for the instantiated words and was followed by a visual lexical decision task in which the instantiated words were mixed with real English words and untrained pseudowords, and the instantiated words were to be considered as words. The phonology‐to‐orthography consistency (feedback consistency) of the instantiated words was manipulated to investigate the role of feedback from phonology in orthographic learning. Masked consonant and vowel‐preserving form primes were used in the lexical decision task as probes of orthographic learning. Feedback‐consistent instantiated words were recognised significantly faster in lexical decision than feedback‐inconsistent instantiated words, and facilitation was significantly greater from consonant‐preserving than vowel‐preserving primes for orally but not visually instantiated words. The results support the hypothesis that orthographic representations based on a consonant frame can be generated from the speech signal before encountering the printed forms, and that feedback from phonology is involved in the early stages of orthographic learning.

Recognition of morphologically complex words in Finnish: Evidence from event-related potentials

The temporal dynamics of processing morphologically complex words was investigated by recording event-related brain potentials (ERPs) when native Finnish-speakers performed a visual lexical decision task. Behaviorally, there is evidence that recognition of inflected nouns elicits a processing cost (i.e., longer reaction times and higher error rates) in comparison to matched monomorphemic words. We aimed to reveal whether the processing cost stems from decomposition at the early visual word form level or from re-composition at the later semantic–syntactic level. The ERPs showed no early effects for morphology, but revealed an interaction with word frequency at a late N400-type component, as well as a late positive component that was larger for inflected words. These results suggest that the processing cost stems mainly from the semantic–syntactic level. We also studied the features of the morphological decomposition route by investigating the recognition of pseudowords carrying real morphemes. The results showed no differences between inflected vs. uninflected pseudowords with a false stem, but differences in relation to those with a real stem, suggesting that a recognizable stem is needed to initiate the decomposition route.

An fMRI study of language processing in people at high genetic risk for schizophrenia

Background Abnormalities in language processing and the related brain structures have been reported in people with schizophrenia. It has been proposed that the brain pathways for language processing are anomalous in these individuals and form the underlying basis for the positive symptoms of the illness. If language pathway abnormalities can be detected early in people at high-risk for schizophrenia prior to the onset of symptoms, early treatment can ensue. Methods Fifteen young adults at high genetic risk for developing schizophrenia were compared with 15 of their siblings with schizophrenia or schizoaffective disorder and 15 age and sex matched individuals at low risk for schizophrenia using a visual lexical decision task during fMRI. The data were analyzed by contrasting activation obtained during a real word–pseudoword discrimination task to activation obtained during a nonlinguistic discrimination task, and the differential activations were examined. Results Patterns of brain activation while reading and discriminating between real and pseudowords differed across groups, with more bilateral activation in schizophrenia patients and their high-risk siblings than controls. In control subjects discrimination of words from psuedowords significantly activated Brodmann's area 44 more strongly than when non-linguistic symbols were discriminated. However, high-risk subjects and their siblings with schizophrenia activated this region similarly for both language and non-language tasks. Conclusions Normal individuals can be distinguished from subjects at high genetic risk for schizophrenia and patients with schizophrenia by their more lateralized and stronger activation of Brodmann's area 44 to word compared with symbol discrimination tasks. Thus, evaluation of language processing by fMRI may be a valuable tool for use in the prediction of individual risk for developing schizophrenia.

Processing of inflected nouns in late bilinguals

This study investigated the recognition of Swedish inflected nouns in two participant groups. Both groups were Finnish-speaking late learners of Swedish, but the groups differed in regard to their Swedish language proficiency. In a visual lexical decision task, inflected Swedish nouns from three frequency ranges were contrasted with corresponding monomorphemic nouns. The reaction times and error rates suggested morphological decomposition for low-frequency inflected words. Yet, both medium- and high-frequency inflected words appeared to possess full-form representations. Despite an overall advantage for the more proficient participants, this pattern was present in both groups. The results indicate that even late exposure to a language can yield such input representations for morphologically complex words that are typical of native speakers.

Processing of inflected nouns in late bilinguals

This study investigated the recognition of Swedish inflected nouns in two participant groups. Both groups were Finnish-speaking late learners of Swedish, but the groups differed in regard to their Swedish language proficiency. In a visual lexical decision task, inflected Swedish nouns from three frequency ranges were contrasted with corresponding monomorphemic nouns. The reaction times and error rates suggested morphological decomposition for low-frequency inflected words. Yet, both medium- and high-frequency inflected words appeared to possess full-form representations. Despite an overall advantage for the more proficient participants, this pattern was present in both groups. The results indicate that even late exposure to a language can yield such input representations for morphologically complex words that are typical of native speakers.

N170 ERPs could represent a logographic processing strategy in visual word recognition.

BackgroundOccipito-temporal N170 component represents the first step where face, object and word processing are discriminated along the ventral stream of the brain. N170 leftward asymmetry observed during reading has been often associated to prelexical orthographic visual word form activation. However, some studies reported a lexical frequency effect for this component particularly during word repetition that appears in contradiction with this prelexical orthographic step. Here, we tested the hypothesis that under word repetition condition, discrimination between words would be operated on visual rather than orthographic basis. In this case, N170 activity may correspond to a logographic processing where a word is processed as a whole.MethodsTo test such an assumption, frequent words, infrequent words and pseudowords were presented to the subjects that had to complete a visual lexical decision task. Different repetition conditions were defined 1 – weak repetition, 2 – massive repetition and 3 – massive repetition with font alternation. This last condition was designed to change visual word shape during repetition and therefore to interfere with a possible visual strategy during word recognition.ResultsBehavioral data showed an important frequency effect for the weak repetition condition, a lower but significant frequency effect for massive repetition, and no frequency effect for the changing font repetition. Moreover alternating font repetitions slowed subject's responses in comparison to "simple" massive repetition.ERPs results evidenced larger N170 amplitude in the left hemisphere for frequent than both infrequent words and pseudowords during massive repetition. Moreover, when words were repeated with different fonts this N170 effect was not present, suggesting a visual locus for such a N170 frequency effect.ConclusionN170 represents an important step in visual word recognition, consisting probably in a prelexical orthographic processing. But during the reading of very frequent words or after a massive repetition of a word, it could represent a more holistic process where words are processed as a global visual pattern.

The impact of affect and frequency on lexical decision: The role of the amygdala and inferior frontal cortex

The current study used event-related fMRI to examine BOLD responses associated with two factors that behaviorally determine speed of lexical decision: frequency and emotion. Thirteen healthy adults performed a visual lexical decision task, discriminating between words and orthographically and phonologically legal nonwords. The study involved a 2 (Frequency: high and low) × 3 (Emotional arousal: highly negative, mildly negative, and neutral words) design with word categories matched for number of letters and concreteness. There were significant main effects for both frequency and emotion in lexical decision reaction times but no significant interaction. Negative word lexical decisions were associated with increased activation in bilateral amygdala and middle temporal cortex as well as rostral anterior and posterior cingulate cortex. Low-frequency word lexical decisions, relative to high-frequency word lexical decisions, were associated with increased bilateral activity in inferior frontal cortex. Inferior frontal cortex activation was particularly low during lexical decision for high-frequency emotional words but significant for high-frequency neutral emotional words. We suggest that this is because the semantic representation of high-frequency emotional words may receive sufficient additional augmentation via the reciprocal activation from the amygdala such that selective augmentation by inferior frontal cortex to achieve lexical decision is unnecessary.

Lexicality and Stimulus Length Effects in Italian Dyslexics: Role of the Overadditivity Effect

The effect of lexicality and stimulus length was studied in 32 third- and fourth-grade Italian dyslexics and in 86 age-matched controls. A visual lexical decision task was used. As proposed by Faust et al. (1999), the results were analyzed in terms of raw reaction time (RT) data and using the z-score transformation to control for the presence of overadditivity effects. In terms of RTs, dyslexics showed a larger difference between words and nonwords (lexicality effect) and between short and long stimuli (length effect) than proficient readers. When data were transformed into z scores, only the group by length interaction remained significant while that with lexicality vanished. This pattern indicates that stimulus length has a specific role in Italian dyslexics’ reading deficit; in contrast, slowness in responding to nonwords was not specific but was interpreted as one aspect of dyslexics’ general inability to deal with alphabetical material (overadditivity effect).

The time course of visual word recognition as revealed by linear regression analysis of ERP data

EEG correlates of a range of psycholinguistic word properties were used to investigate the time course of access to psycholinguistic information during visual word recognition. Neurophysiological responses recorded in a visual lexical decision task were submitted to linear regression analysis. First, 10 psycholinguistic features of each of 300 stimulus words were submitted to a principal component analysis, which yielded four orthogonal variables likely to reflect separable processes in visual word recognition: Word length, Letter n-gram frequency, Lexical frequency and Semantic coherence of a word's morphological family. Since the lexical decision task required subjects to distinguish between words and pseudowords, the binary variable Lexicality was also investigated using a factorial design. Word–pseudoword differences in the event-related potential first appeared at 160 ms after word onset. However, regression analysis of EEG data documented a much earlier effect of both Word length and Letter n-gram frequency around 90 ms. Lexical frequency showed its earliest effect slightly later, at 110 ms, and Semantic coherence significantly correlated with neurophysiological measures around 160 ms, simultaneously with the lexicality effect. Source estimates indicated parieto-temporo-occipital generators for the factors Length, Letter n-gram frequency and Word frequency, but widespread activation with foci in left anterior temporal lobe and inferior frontal cortex related to Semantic coherence. At later stages (>200 ms), all variables exhibited simultaneous EEG correlates. These results indicate that information about surface form and meaning of a lexical item is first accessed at different times in different brain systems and then processed simultaneously, thus supporting cascaded interactive processing models.

T-value and mutual information as measures of the association strength in Serbian language

Since the study of Meyer and Schvaneveldt (1971), a large number of researches have shown facilitation effect in cognitive processing of a given word when it is preceded by a semantically (i.e. associatively) related word. In this study, we examined influence of association strength between context and target on visual word processing in Serbian language. Primary goal was to test cognitive relevance of the t-value and mutual information (MI) as measures of the association strength. The results showed that the mutual information affects response latencies in the visual lexical decision task: the higher the mutual information for two words (bigram), the shorter the reaction time. Contrariwise, cognitive relevance of the t-value as a measure of the words' association strength was not confirmed.

Incidental effects of emotional valence in single word processing: An fMRI study

The present study aimed at identifying the neural responses associated with the incidental processing of the emotional valence of single words using event-related functional magnetic resonance imaging (fMRI). Twenty right-handed participants performed a visual lexical decision task, discriminating between nouns and orthographically and phonologically legal nonwords. Positive, neutral and negative word categories were matched for frequency, number and frequency of orthographic neighbors, number of letters and imageability. Response times and accuracy data differed significantly between positive and neutral, and positive and negative words respectively, thus, replicating the findings of a pilot study. Words showed distributed, mainly left hemisphere activations, indicating involvement of a neural network responsible for semantic word knowledge. The neuroimaging data further revealed areas in left orbitofrontal gyrus and bilateral inferior frontal gyrus with greater activation to emotional than to neutral words. These brain regions are known to be involved in processing semantic and emotional information. Furthermore, distinct activations associated with positive words were observed in bilateral middle temporal and superior frontal gyrus, known to support semantic retrieval, and a distributed network, namely anterior and posterior cingulate gyrus, lingual gyrus and hippocampus when comparing positive and negative words. The latter areas were previously associated with explicit and not incidental processing of the emotional meaning of words and emotional memory retrieval. Thus, the results are discussed in relation to models of processing semantic and episodic emotional information.

The effects of homonymy and polysemy on lexical access: an MEG study

We examined the neural correlates of semantic ambiguity by measuring changes in MEG recordings during a visual lexical decision task in which the properties of ambiguous words were manipulated. Words that are ambiguous between unrelated meanings (like bark, which can refer to a tree or to a dog) were accessed more slowly than words that have no unrelated meanings (such as cage). In addition, words that have many related senses (e.g., belt, which can be an article of clothing or, closely related in sense, a fan belt used in machinery) were accessed faster than words that have few related senses (e.g., ant). The findings are inconsistent with accounts that posit that both kinds of ambiguity involve separate lexical entries, but instead offer both behavioral and neurophysiological support for separate entry accounts only for homonymy, and a single-entry model of polysemy. The findings also provide neural correlates for a behavioral study of lexical ambiguity that demonstrated that the frequently reported ambiguity advantage in lexical decision tasks is not due to the presence of many unrelated meanings but to the presence of many related senses.

Herkenning Van Homografen Door Tweetaligen

In two experiments, we investigated how words with cross-linguistic overlap in orthography and/or phonology are recognized by bilinguals. Dutch-English bilinguals performed an English visual lexical decision task including words that are spelled and/or pronounced the same in English and Dutch. Earlier studies by Dijkstra et al (1999) and Lemhöfer & Dijkstra (2004) showed seemingly contradictory results. For example, in the first study, homophones were reacted to significantly more slowly, whereas homophones produced facilitation in the second study. However, the previous studies had problems with the frequency distribution of the stimuli and the control conditions. Therefore, the experimental design was improved in Experiments 1 and 2 in order to find out how interlingual homographs are recognized by bilinguals and what the influence is of orthographic and phonological overlap. Experiment 1, with homographs with only orthographic overlap and homographs with both orthographic and phonological overlap, partly replicated results found by Dijkstra et al. and Lemhöfer & Dijkstra, but did not show the null-effect for homographs with both orthographic and phonological overlap. Because the major difference between the three studies was stimulus list composition, Experiment 2 tested whether a change in stimulus list composition influenced the reaction times to interlingual homographs. Experiment 2 included homographs with both orthographic and phonological overlap and homophones. In this experiment, homophones produced a null-effect and the homographs were reacted to significantly more slowly than control words. The results imply that a change in stimulus list composition influences reaction times to interlingual homographs, because it can induce different types of participant strategies.

The influence of phonological neighborhood on visual word perception

In the research reported here, we investigated the influence of phonological neighborhood density on the processing of words in the visual lexical decision task. The results of the first experiment revealed that words with large phonological neighborhoods were verified more rapidly than words with small phonological neighborhoods. In the second experiment, we replicated this effect with a more tightly controlled set of stimuli. These results demonstrate the importance of phonological codes when processing visually presented letter strings. We relate this research to previous results on semantic and orthographic neighborhoods and discuss the results within the context of a model in which lexical decisions are based on stimulus familiarity.

Orthographic neighborhood and concreteness effects in the lexical decision task

The experiment reported here investigated the sensitivity of concreteness effects to orthographic neighborhood density and frequency in the visual lexical decision task. The concreteness effect was replicated with a sample of concrete and abstract words that were not matched for orthographic neighborhood features and in which concrete words turned out to have a higher neighborhood density than abstract words. No consistent effect of concreteness was found with a sample of concrete and abstract words matched for orthographic neighborhood density and frequency and having fewer neighbors and higher-frequency neighbors than the words of the first sample. Post hoc analyses of the results showed that orthographic neighborhood density was not a nuisance variable producing a spurious effect of concreteness but, instead, that the existence of higher-frequency neighbors constitutes a necessary condition for concreteness effects to appear in the lexical decision task. This finding is consistent with the hypothesis that semantic information is accessed and used to generate the responses in lexical decision when inhibition from orthographic forms delays the target word recognition.

How word frequency affects morphological processing in monolinguals and bilinguals

The present study investigated processing of morphologically complex words in three different frequency ranges in monolingual Finnish speakers and Finnish-Swedish bilinguals. By employing a visual lexical decision task, we found a differential pattern of results in monolinguals vs. bilinguals. Monolingual Finns seemed to process low frequency and medium frequency inflected Finnish nouns mostly by morpheme-based recognition but high frequency inflected nouns through full-form representations. In contrast, bilinguals demonstrated a processing delay for all inflections throughout the whole frequency range, suggesting decomposition for all inflected targets. This may reflect different amounts of exposure to the word forms in the two groups. Inflected word forms that are encountered very frequently will acquire full-form representations, which saves processing time. However, with the lower rates of exposure, which characterize bilingual individuals, full-form representations do not start to develop.

Access to knowledge from pictures but not words in a patient with progressive fluent aphasia

We present data from a patient with a progressive fluent aphasia, BA, who exhibited a severe verbal impairment but a relatively preserved access to knowledge from pictures. She exhibited surface dyslexia and dysgraphia and was impaired in the production of the past tense of irregular verbs and the plural form of irregular nouns. She exhibited a mild-moderate impairment in auditory and visual lexical decision tasks that, we argue, was explicable on the basis of a semantic deficit. Knowledge of numbers and body parts was largely preserved even when on tasks involving verbal stimuli. On the basis of this and other evidence, we argue for a distributed, multi-modality system for semantic memory in which information is stored in different brain regions and in different representational formats.

Cross-task strategic effects.

When easy and difficult items are mixed together, their reading aloud latencies become more homogeneous relative to their presentation in unmixed ("pure") conditions (Lupker, Brown, & Colombo, 1997). We report two experiments designed to investigate the nature of the mechanism that underlies this list composition, or blocking, effect. In Experiment 1, we replicated Lupker et al.'s (1997) blocking effect in the reading aloud task and extended these findings to the visual lexical decision task. In Experiment 2, we found that blocking effects generalized across tasks: The characteristics of stimuli in a visual lexical decision task influenced reading aloud latencies, and vice versa, when visual lexical decision and reading aloud trials were presented alternately in the same experiment. We discuss implications of these results within time-criterion (Lupker et al., 1997) and strength-of-processing (Kello & Plaut, 2000, 2003) theories of strategic processing in reading.

Sensitivity to prosodic structure in left- and right-hemisphere-damaged individuals

An experiment was conducted in order to determine whether left- (LHD) and right-hemisphere-damaged (RHD) patients exhibit sensitivity to prosodic information that is used in syntactic disambiguation. Following the work of Marslen-Wilson, Tyler, Warren, Grenier, and Lee, and Lee (1992)1992, a cross-modal lexical decision task was performed by LHD and RHD subjects, as well as by adults without brain pathology (NC). Subjects listened to sentences with attachment ambiguities with either congruent or incongruent prosody, while performing a visual lexical decision task. Results showed that each of the unilaterally damaged populations differed from each other, as well as from the NCs in terms of sensitivity regarding prosodic cues. Specifically, the RHD group was insensitive to sentence prosody as a whole. This was in contrast to the LHD patients, who responded to the prosodic manipulation, but in the unexpected direction. Results are discussed in terms of current hypotheses regarding the hemispheric lateralization of prosodic cues.

On recognizing proper names: The orthographic cue hypothesis

Five experiments investigated the recognition of proper names and common nouns using the lexical decision paradigm. In Experiments 1–3 the case of the initial letter of written stimuli was systematically varied. An advantage was consistently found for proper names written with the first letter in capital. Crucially, response times to proper names with the first letter in lowercase and to common nouns irrespective of the case of the first letter did not differ from each other. No difference between proper names and common nouns emerged in Experiment 4 where the stimuli were presented auditorily, and in Experiment 5 where a visual lexical decision task was performed with illegal non-words. The pattern of results shows that the proper name advantage is orthographic in nature and rules out an account in terms of semantic, morphological or other lexical variables. A model is proposed in which information about the case of the first letter is specified in the abstract multidimensional orthographic representation mediating written word recognition.