Lexical decision in children: sublexical processing or lexical search?

Length effects in the lexical decision latencies of children might indicate that children rely on sublexical processing and essentially approach the task as a naming task. We examined this possibility by means of the effects of neighbourhood size and articulatory suppression on lexical decision performance. Sixty-six beginning and 62 advanced readers performed a lexical decision task in a standard, articulatory suppression, or tapping condition. We found length effects on words and nonwords in the children's lexical decisions. However, the effects of neighbourhood size were similar to those reported for adult lexical decisions, rather than the effects previously found in children's naming. In addition, no effect was found of articulatory suppression. Both findings suggest that, despite clear length effects, children do not adopt a naming task approach but, like adults, base lexical decisions mainly on a lexical search. These results pose a challenge for several computational models of reading.     

Is the go/no-go lexical decision task an alternative to the yes/no lexical decision task?

In the go/no-go lexical decision task (LDT), participants are instructed to respond as quickly as they can when a word is presented and not to respond if a nonword is presented. By minimizing part of the response selection process in the experimental task, the impact of response decision time on the obtained lexical decision time is probably reduced relative to the standard yes/no LDT (Gordon, 1983). Experiments 1 and 2 show that the go/no-go LDT is sensitive to the effects of word frequency and associative priming--the magnitude of these effects is similar with the two tasks. More important, the go/no-go LDT has a number of advantages with respect to the "standard" yes/no LDT: It offers faster response times, more accurate responding, and fewer processing demands than does the yes/no task. Accordingly, the go/no-go task appears to be an excellent alternative to the standard yes/no task.     

Cognate effects in sentence context depend on word class,L2 proficiency,and task

Length effects in the lexical decision latencies of children might indicate that children rely on sublexical processing and essentially approach the task as a naming task. We examined this possibility by means of the effects of neighbourhood size and articulatory suppression on lexical decision performance. Sixty-six beginning and 62 advanced readers performed a lexical decision task in a standard, articulatory suppression, or tapping condition. We found length effects on words and nonwords in the children's lexical decisions. However, the effects of neighbourhood size were similar to those reported for adult lexical decisions, rather than the effects previously found in children's naming. In addition, no effect was found of articulatory suppression. Both findings suggest that, despite clear length effects, children do not adopt a naming task approach but, like adults, base lexical decisions mainly on a lexical search. These results pose a challenge for several computational models of reading.     

A diffusion model account of normal and impaired readers

Acquired aphasics and dyslexics with even very profound word reading impairments have been shown to perform relatively well on the lexical decision task, but direct contrasts with unimpaired participant's data is often complicated by extremely long reaction times for patient data. The dissociation between lexical decision and word naming performance shown by these patients is of theoretical importance, and here we present an analysis of processing underlying the lexical decision task. We are able to determine what aspects of performance are affected by acquired aphasics in the lexical decision task. We fit lexical decision data from aphasic patients and from normal readers with a sequential sampling model (the diffusion model) that simultaneously considers reaction time and accuracy. This model provides a powerful means of assessing processes involved in impaired and unimpaired lexical decision. Our results suggest that lexical decision may tap impairments at both a linguistic and a nonlinguistic level. These impairments combine to make patients produce the exaggerated lexical decision reaction times typical of neurolinguistic patients: we demonstrate that patients have compromised decision and nondecision processes but that the quality of the information upon which they base their decisions is not much different from that of unimpaired participants.     

How semantic is automatic semantic priming?

Priming for semantically related concepts was investigated using a lexical decision task designed to reveal automatic semantic priming. Two experiments provided further evidence that priming in a single presentation lexical decision task (McNamara & Altarriba, 1988) derives from automatic processes. Mediated priming, but no inhibition or backward priming was found in this type of lexical decision task. Experiments 3 and 4 demonstrated that automatic priming was found only for associated word pairs, as determined by word association norms, and not for word pairs that are semantically related but not associated. It is argued that automatic priming in the lexical decision task occurs at a lexical level not at a semantic level.     

A transfer analysis of the repetition effect in the lexical and ambiguity decision tasks

Two experiments were performed in an attempt to evaluate explanations of repetition priming-the facilitation observed when the same word is processed a second time in the same task. One task employed was lexical decision (word/nonword) and the other was ambiguity decision (ambiguous/ unambiguous). In the first experiment, transfer on a lexical decision task was measured following either a lexical decision or an ambiguity decision. When the identical lists were processed in the first phase for lexical and ambiguity decision, equal repetition effects were obtained on lexical decision. However, when the ambiguity task was presented without nonwords, no repetition priming occurred. In a second experiment, the within-task repetition effect was large for the ambiguity decision, whereas no transfer was obtained from lexical decision to ambiguity decision. The results were interpreted as being consistent with a transfer-appropriate processing account of repetition priming.     

An event-related brain potential analysis of visual word priming effects

Two experiments are reported that provide evidence on task-induced effects during visual lexical processing in a prime-target semantic priming paradigm. The research focuses on target expectancy effects by manipulating the proportion of semantically related and unrelated word pairs. In Experiment 1, a lexical decision task was used and reaction times (RTs) and event-related brain potentials (ERPs) were obtained. In Experiment 2, subjects silently read the stimuli, without any additional task demands, and ERPs were recorded. The RT and ERP results of Experiment 1 demonstrate that an expectancy mechanism contributed to the priming effect when a high proportion of related word pairs was presented. The ERP results of Experiment 2 show that in the absence of extraneous task requirements, an expectancy mechanism is not active. However, a standard ERP semantic priming effect was obtained in Experiment 2. The combined results show that priming effects due to relatedness proportion are induced by task demands and are not a standard aspect of online lexical processing.     

Are lexical decisions a good measure of lexical access? The role of word frequency in the neglected decision stage

Three experiments investigated the impact of five lexical variables (instance dominance, category dominance, word frequency, word length in letters, and word length in syllables) on performance in three different tasks involving word recognition: category verification, lexical decision, and pronunciation. Although the same set of words was used in each task, the relationship of the lexical variables to reaction time varied significantly with the task within which the words were embedded. In particular, the effect of word frequency was minimal in the category verification task, whereas it was significantly larger in the pronunciation task and significantly larger yet in the lexical decision task. It is argued that decision processes having little to do with lexical access accentuate the word-frequency effect in the lexical decision task and that results from this task have questionable value in testing the assumption that word frequency orders the lexicon, thereby affecting time to access the mental lexicon. A simple two-stage model is outlined to account for the role of word frequency and other variables in lexical decision. The model is applied to the results of the reported experiments and some of the most important findings in other studies of lexical decision and pronunciation.     

Visual word recognition of single-syllable words

Speeded visual word naming and lexical decision performance are reported for 2428 words for young adults and healthy older adults. Hierarchical regression techniques were used to investigate the unique predictive variance of phonological features in the onsets, lexical variables (e.g., measures of consistency, frequency, familiarity, neighborhood size, and length), and semantic variables (e.g. imageahility and semantic connectivity). The influence of most variables was highly task dependent, with the results shedding light on recent empirical controversies in the available word recognition literature. Semantic-level variables accounted for unique variance in both speeded naming and lexical decision performance, level with the latter task producing the largest semantic-level effects. Discussion focuses on the utility of large-scale regression studies in providing a complementary approach to the standard factorial designs to investigate visual word recognition.     

Locus of inhibition effects in the priming of lexical decisions: pre- or postlexical access?

The lexical decision task has been employed to investigate the effects of semantic context on word recognition. A frequent finding from the task is that “word” responses are slower when the target is preceded by an unrelated word than when it is preceded by a neutral stimulus. This inhibition effect has been interpreted as indicating that the unrelated prime interferes with word-recognition processes operating on the target. In three experiments, the effects of unrelated primes were compared for a lexical decision and word naming task. Although large inhibition effects were found for the lexical decision task in all experiments, no inhibition effects were observed for the naming task. The results are interpreted as demonstrating that inhibition effects in the lexical decision task are not on recognition processes; rather they are located at processes operating after recognition of the target has occurred.     

Influence of mild cognitive impairment on visual word recognition

The present study examined the effects of normal aging and mild cognitive impairment (MCI) on visual word recognition. Madden et al. (1999) reported evidence of general slowing of cognitive processes in Alzheimer's disease (AD) patients relative to younger adults and healthy older adults using a lexical decision task. It was of interest to determine whether similar effects would be observed in MCI patients relative to healthy younger and older adults. We extended the lexical decision task paradigm developed by Allen et al. (2004b) on younger adults to an examination of the effect(s) of MCI on visual word recognition. Results from the present study showed that healthy older adults and MCI patients performed similarly. That is, both groups took longer than younger adults to process words presented in mixed-case than in consistent-case letters. Mild cognitive impairment patients, however, responded significantly more slowly than healthy older adults across all lexical decision task conditions and showed a trend toward larger case-mixing effects than healthy older adults, which suggests that MCI may result in poorer analytic processing ability. Based on the current findings, evidence of a generalized slowing of cognitive processes using a standard lexical decision task can be expanded to include not only AD patients, but also the preclinical stages of the disease as well.     

Semantic size does not matter: "bigger" words are not recognized faster

Sereno, O'Donnell, and Sereno (2009) reported that words are recognized faster in a lexical decision task when their referents are physically large than when they are small, suggesting that "semantic size" might be an important variable that should be considered in visual word recognition research and modelling. We sought to replicate their size effect, but failed to find a significant latency advantage in lexical decision for "big" words (cf. "small" words), even though we used the same word stimuli as Sereno et al. and had almost three times as many subjects. We also examined existing data from visual word recognition megastudies (e.g., English Lexicon Project) and found that semantic size is not a significant predictor of lexical decision performance after controlling for the standard lexical variables. In summary, the null results from our lab experiment--despite a much larger subject sample size than Sereno et al.--converged with our analysis of megastudy lexical decision performance, leading us to conclude that semantic size does not matter for word recognition. Discussion focuses on why semantic size (unlike some other semantic variables) is unlikely to play a role in lexical decision.     

How to say "no" to a nonword: a leaky competing accumulator model of lexical decision

We describe a leaky competing accumulator (LCA) model of the lexical decision task that can be used as a response/decision module for any computational model of word recognition. The LCA model uses evidence for a word, operationalized as some measure of lexical activity, as input to the YES decision node. Input to the NO decision node is simply a constant value minus evidence for a word. In this way, evidence for a nonword is a function of time from stimulus onset (as in standard deadline models) modulated by lexical activity via the competitive dynamics of the LCA. We propose a simple mechanism for determining the value of this constant online during the first trials of a lexical decision experiment, such that the model can rapidly optimize speed and accuracy in discriminating words from nonwords. Further optimization is achieved via trial-by-trial adjustments in response criteria as a function of task demands and list context. We show that the LCA model can simulate mean response times and response distributions for correct and incorrect YES and NO decisions for a number of benchmark experiments that have been shown to be fatal for deadline models of lexical decision. Finally, using lexical activity calculated by a computational model of word recognition as input to the LCA decision module, we provide the first item-level simulation of both word and nonword responses in a large-scale database.     

Case alternation effect: Two types of word recognition?

Two experiments were conducted to test Besner's (1983) claim that the lexical decision task involves a type of recognition mechanism that simply monitors the visual familiarity of the target without uniquely specifying the word. The experiments tested the combined effects of case alternation and decision type, and case alternation and word frequency in a lexical decision task and in a task requiring speeded decisions about the syntactic usage of target words. Contrary to Besner's proposal, case alternation did not affect word decisions more than nonword decisions in the lexical decision task. Further, the finding of additive effects of case alternation and word frequency in the two tasks was also at odds with the prediction derived from Besner's account. The discrepancy between the results obtained by Besner and the present lexical decision task was discussed in terms of different decision strategies, and it was suggested that under conditions of difficult word-nonword discrimination, the global visual familiarity of the target is not involved in making lexical decisions.     

A word’s meaning affects the decision in lexical decision

The influence of an isolated word’s meaning on lexical decision reaction time (RT) was demonstrated through four experiments. Subjects in two experiments made lexical decision judgments, those in a third experiment pronounced the words used in the lexical decision task, and those in a fourth experiment quickly pronounced their first associative response to the words. Differences in lexical access time for the words were measured with the pronunciation task, and differences in meaning were assessed with the association task. Multiple regression analyses of lexical decision RT were conducted using associative RT, pronunciation RT, and other target word properties (printed frequency, length, instance dominance, and number of dictionary meanings) as predictor variables. These analyses revealed a relationship between lexical decision RT and associative RT after the effects of other variables had been partialed out. In addition, word frequency continued to have a significant relationship to lexical decision RT beyond that shared with pronunciation RT and the other variables. The results of these experiments indicate that at least some of the effect of word meaning and word frequency in lexical decision is attributable to a decision stage following lexical access.     

Masked nonword repetition effects in yes/no and go/no-go lexical decision: A test of the evidence accumulation and deadline accounts

The pattern of masked repetition priming effects for word and nonword targets differs across tasks: Maskedpriming effects in lexical decision occur for positive responses (i.e., words), but not for negative responses (nonwords), whereas masked-priming effects in the cross-case same-different task occur for positive responses (same), but not for negative responses (different)—regardless of lexical status. Here, we examined whether masked nonword priming effects are greater when the task involves an active go response to nonwords than when it involves the standard yes/no procedure in lexical decision. The obtained masked repetition priming effect for nonwords was of similar size in yes/no and go/no-go tasks. This finding is compatible with accounts of nonword priming that posit that nonword responses are produced by actively accumulating evidence for the nonword alternative in yes/no and go/no-go procedures, whereas it is inconsistent with the assumption of a deadline for no responses in the yes/no task.     

The cost of remembering to remember in event-based prospective memory: investigating the capacity demands of delayed intention performance

Prospective memory tasks are often accomplished during the performance of other activities. Despite the dual-task nature of prospective memory, little attention has been paid to how successful prospective memory performance affects ongoing activities. In the first 2 experiments, participants performing an embedded prospective memory task had longer response times on nonprospective memory target trials of a lexical decision task than participants performing the lexical decision task alone. In the prospective memory groups, longer lexical decision response times were associated with better prospective memory performance (Experiments 1, 2, and 3), a pattern not demonstrated with an embedded retrospective memory task (Experiment 2). The results of Experiment 3 suggest that the retrieval of a delayed intention, or the prospective component, can require capacity.     

On the relation between feeling of knowing and lexical decision: persistent subthreshold activation or topic familiarity?

Experiment 1 replicated Yaniv and Meyer's (1987) finding that lexical decision and episodic recognition performance was better for words previously yielding high-accessibility levels (a combination of feeling-of-knowing and tip-of-the-tongue ratings) in comparison with those yielding low-accessibility levels in a rare word definition task. Experiment 2 yielded the same pattern even though lexical decisions preceded accessibility estimates by a full week. Experiment 3 dismissed the possibility that the Experiment 2 results may have been due to a long-term influence from the lexical decision task to the rare word judgment task. These results support a model in which Ss (a) retrieve topic familiarity information in making accessibility estimates in the rare word definition task and (b) use this information to modulate lexical decision performance.     

Is the go/no-go lexical decision task preferable to the yes/no task with developing readers?

The lexical decision task is probably the most common laboratory visual word identification task together with the naming task. In the usual setup, participants need to press the “yes” button when the stimulus is a word and the “no” button when the stimulus is not a word. A number of studies have employed this task with developing readers; however, error rates and/or response times tend to be quite high. One way to make the task easier for young readers is by employing a go/no-go procedure: “If word, press ‘yes’; if not, refrain from responding.” Here we conducted a lexical decision experiment that systematically compared the yes/no and go/no-go variants of the lexical decision task with developing readers (second- and fourth-grade children). Results showed that (a) error rates for words and nonwords were much lower in the go/no-go task than in the yes/no task, (b) lexical decision times were substantially faster in the go/no-go task, and (c) there was less variability in the latency data of the go/no-go task for high-frequency words. Thus, the go/no-go lexical decision task is preferable to the “standard” yes/no task when conducting experiments with developing readers.     

Influence of neighborhood size and exposure duration on visual-word recognition: evidence with the yes/no and the go/no-go lexical decision tasks

We present two experiments in which we measured lexical decision latencies and errors to words with few or many orthographic neighbors (ie., Coltheart's N). The main goal of the study was to examine whether or not the neighborhood size effect in a lexical decision task could be affected by the exposure duration of the stimulus item (unlimited vs. limited time exposure, 150 msec plus a backward mask) and the type of decision involved in the task (yes/no vs. go/no-go lexical decision tasks). In the yes/no task, the results showed a facilitative neighborhood size effect for low frequency that did not interact with exposure duration (Experiment 1). In contrast, in the go/no-go task (in this task, participants are instructed to respond as quickly as they can when a word is presented and not to respond if a nonword is presented), the neighborhood size effect for low-frequency words (and for nonwords) was greater under limited viewing time (Experiment 2). In addition, the word frequency effect was greater in the go/no-go task than in the yes/no task, replicating Hino and Lupker (1998, 2000). The results were interpreted in terms of the interaction of decision and lexical factors in visual-word recognition.