Lateralization effects in lexical decision tasks

Subjects were timed as they judged whether items presented to them were English words or not. Comparisons were made between responses to nouns and to verbs, on the one hand, and between concrete and abstract nouns, on the other hand. No asymmetries were found.     

Age-of-acquisition effects in lexical and episodic memory tasks

This paper reports four experiments on the effects of word age of acquisition in verbal tasks. In all cases, multiple-regression analysis was used to assess the relative effects of age as opposed to other potentially relevant word attributes. Experiments 1 and 2 concerned lexical memory tasks. In Experiment 1, picture naming speeds were found to be mainly determined by picture codability and name age of acquisition. In Experiment 2, it was found that when subjects produced words in response to bigram cues, early acquired target words were more likely to be produced than later acquired words, even when frequency and other word attributes were taken into account. The remaining two experiments dealt with the episodic memory tasks of free recall and recognition. No age effects were found in these tasks. It was concluded that early age of acquisition facilitates retrieval from lexical memory but has no significant effect in episodic memory tasks.     

Attention and implicit memory in the category-verification and lexical decision tasks

Prior research on implicit memory appeared to support 3 generalizations: Conceptual tests are affected by divided attention, perceptual tasks are affected by certain divided-attention manipulations, and all types of priming are affected by selective attention. These generalizations are challenged in experiments using the implicit tests of category verification and lexical decision. First, both tasks were unaffected by divided-attention tasks known to impact other priming tasks. Second, both tasks were unaffected by a manipulation of selective attention in which colored words were either named or their colors identified. Thus, category verification, unlike other conceptual tasks, appears unaffected by divided attention, and some selective-attention tasks, and lexical decision, unlike other perceptual tasks, appears unaffected by a difficult divided-attention task and some selective-attention tasks. Finally, both tasks were affected by a selective-attention task in which attention was manipulated across objects (rather than within objects), indicating some susceptibility to selective attention. The results contradict an analysis on the basis of the conceptual-perceptual distinction and other more specific hypotheses but are consistent with the distinction between production and identification priming.     

Relations between emotion,memory, and attention: Evidence from taboo Stroop,lexical decision,and immediate memory tasks

This article reports five experiments demonstrating theoretically coherent effects of emotion on memory and attention. Experiments 1-3 demonstrated three taboo Stroop effects that occur when people name the color of taboo words. One effect is longer color-naming times for taboo than for neutral words, an effect that diminishes with word repetition. The second effect is superior recall of taboo words in surprise memory tests following color naming. The third effect is better recognition memory for colors consistently associated with taboo words rather than with neutral words. None of these effects was due to retrieval factors, attentional disengagement processes, response inhibition, or strategic attention shifts. Experiments 4 and 5 demonstrated that taboo words impair immediate recall of the preceding and succeeding words in rapidly presented lists but do not impair lexical decision times. We argue that taboo words trigger specific emotional reactions that facilitate the binding of taboo word meaning to salient contextual aspects, such as occurrence in a task and font color in taboo Stroop tasks.     

Dissociated backward priming effects in lexical decision and pronunciation tasks

Backward priming was examined at 150- and 500-msec prime-target stimulus onset asynchronies (SOAs) using visually presented primes and targets in lexical decision and pronunciation tasks. Two kinds of backward relations were used: compound items for which targets and primes formed a word in the backward direction (e.g., prime: HOP; target: bell), and noncompound items for which targets and primes did not form a word but were associatively related in the backward but not the forward direction (e.g., prime: BABY; target: stork). Results showed that backward priming effects were equivalent for compounds and noncompounds. However, for lexical decisions, backward priming occurred at both SOAs, whereas for pronunciation, it occurred only at the 150-msec SOA. We discuss how this SOA-dissociated backward priming effect in lexical decision and pronunciation tasks poses a serious challenge for all theories of semantic priming.     

Context effects on lexical choice and lexical activation

Speakers are regularly confronted with the choice among lexical alternatives when referring to objects, including basic-level names (e.g., car) and subordinate-level names (e.g., Beetle). Which of these names is eventually selected often depends on contextual factors. The present article reports a series of picture-word interference experiments that explored how the designated target name (basic level vs. subordinate level) and contextual constraints rendering the name alternative either appropriate or inappropriate affect lexical activation and lexical choice. The experimental data demonstrate clear context effects on the eventual lexical choice. However, they also show that alternative nonselected object names are phonologically activated, even if a constraining context makes these alternative names currently inappropriate.     

Concreteness and context availability in lexical decision tasks

Three experiments were carried out to elucidate the origins of the concreteness (C) effect in a lexical decision task. The first experiment was a replication of the work of Schwanenflugel et al. (1988) and Van Hell and De Groot (1998), who presented the context availability (CA) hypothesis. In this experiment CA seemed to be a dominant factor. Familiarity (FAM) was not incorporated in the ANOVA, but a regression analysis and negative correlation between C and FAM in the groups matched on CA showed that FAM could explain the disappearance of the C effect. Experiment 2 controlled FAM and revealed a C effect, although concrete and abstract words were matched on CA. Experiment 3 controlled C and FAM and revealed a CA effect. The current data emphasize the importance of controlling FAM and CA in examining the C effect in a lexical decision task and support a revised version of the dual-coding theory.     

Turning an advantage into a disadvantage: Ambiguity effects in lexical decision versus reading tasks

When performing a lexical decision task, participants can correctly categorize letter strings as words faster if they have multiple meanings (i.e., ambiguous words) than if they have one meaning (i.e., unambiguous words). In contrast, when reading connected text, participants tend to fixate longer on ambiguous words than on unambiguous words. Why are ambiguous words at an advantage in one word recognition task, and at a disadvantage in another? These disparate results can be reconciled if it is assumed that ambiguous words are relatively fast to reach a semantic-blend state sufficient for supporting lexical decisions, but then slow to escape the blend when the task requires a specific meaning be retrieved. We report several experiments that support this possibility.     

The effects of progressive sleep loss on a lexical decision task: Response lapses and response accuracy

A lexical decision task was used in a paradigm testing the effects of sleep loss and fatigue on performance during a 72-h period of sleep deprivation. The data were partitioned into categories of response lapses, response accuracy, and the signal detection measures of discriminability (d’) and bias (β). Response lapses increased as a function of sleep loss and were fitted best by a composite equation with a major linear component and a minor rhythmic component. Response accuracy decreased as a function of sleep loss, with the rate of decrease being greater for nonwords than for words. Although d’ was higher for right visual field (RVF), it decreased for both fields almost linearly as a function of sleep deprivation. The rate of decrease for RVF stimulation was greater than for left visual field (LVF) stimulation, β did not change monotonically as a function of sleep loss, but showed strong circadian rhythmicity, indicating that it was not differentially affected by sleep loss per se.     

Decoding digit symbol: speed,memory, and visual scanning

The authors evaluated the relative contributions of speed, memory, and visual scanning to Digit Symbol score in a sample of young adults (N = 87). Speed (Symbol Copy) explained 35% of Digit Symbol variance; only half of this was attributable to graphomotor speed (Name Printing), implying a role for perceptual speed. Visual-scanning tests (e.g., Symbol Scan) explained (on average) 34% of Digit Symbol variance, much of which was independent of perceptual-motor speed, establishing an important role for visual-scanning efficiency in Digit Symbol performance. By contrast, memory tests (on average) explained only 4% to 5% of Digit Symbol variance: statistically significant but clearly subsidiary, although a visual memory composite correlated more strongly with Digit Symbol. The Digit Symbol incidental learning procedures did, however, correlate moderately with other memory measures, suggesting that they are valid memory screening devices.     

Ambiguity and synonymy effects in lexical decision,naming, and semantic categorization tasks: interactions between orthography,phonology, and semantics

In this article, ambiguity and synonymy effects were examined in lexical decision, naming, and semantic categorization tasks. Whereas the typical ambiguity advantage was observed in lexical decision and naming, an ambiguity disadvantage was observed in semantic categorization. In addition, a synonymy effect (slower latencies for words with many synonyms than for words with few synonyms) was observed in lexical decision and naming but not in semantic categorization. These results suggest that (a) an ambiguity disadvantage arises only when a task requires semantic processing, (b) the ambiguity advantage and the synonymy disadvantage in lexical decision and naming are due to semantic feedback, and (c) these effects are determined by the nature of the feedback relationships from semantics to orthography and phonology.     

How normal and retarded individuals monitor and regulate speed and accuracy of responding in serial choice tasks

These experiments investigate whether or not differences in the way that retarded and nonretarded individuals monitor and regulate speed and accuracy of responding contribute to the slower and more variable performance of retarded subjects on choice reaction time (RT) tasks. Rabbitt (1979, 1981) suggested that efficient choice RT performance is mediated by subjects tracking increasingly faster RT bands on successive trials until, by making and recognizing errors, they discover those very fast RT levels that should be avoided and those safe bands, just above typical error levels, that should be tracked. Experiments 1A and 1B established that most retarded subjects detect their errors as efficiently as nonretarded controls, a finding that excludes the possibility that retarded subjects do not monitor accuracy efficiently but achieve comparable levels of accuracy by consistently responding within very slow RT bands that minimize likelihood of errors. Experiment 2 showed that while a qualitatively similar trial-by-trial tracking mechanism mediates the performance of both groups, retarded subjects are less efficient at constraining RTs within very fast, but safe, bands. Increasing error probabilities at longer RTs suggest that momentary fluctuations in stimulus discriminability and/or attention are factors affecting RT variability in retarded subjects. The RT patterns for various sequences of correct responses initiated and terminated by errors suggest that the effective past experience (EPEX) guiding trial-by-trial RT adjustments of retarded subjects is short and inadequate, and it was argued that this can account for much of the remaining RT variability contributing to retarded-nonretarded differences. Not only does a short EPEX increase variability by giving rise to long error-free sequences of slower than average RT but also, when combined with occasional specified random fluctuations, it suggests why retarded subjects can achieve, but not sustain, RT levels maintained by nonretarded subjects.     

The impact of feedback semantics in visual word recognition: number-of-features effects in lexical decision and naming tasks

The notion of feedback activation from semantics to both orthography and phonology has recently been used to explain a number of semantic effects in visual word recognition, including polysemy effects (Hino & Lupker, 1996; Pexman & Lupker, 1999) and synonym effects (Pecher, 2001). In the present research, we tested an account based on feedback activation by investigating a new semantic variable: number of features (NOF). Words with high NOF (e.g., LION) should activate richer semantic representations than do words with low NOF (e.g., LIME). As a result, the feedback activation from semantics to orthographic and phonological representations should be greater for high-NOF words, which should produce superior lexical decision task (LDT) and naming task performance. The predicted facilitory NOF effects were observed in both LDT and naming.     

Individual differences in memory span: The contribution of rehearsal, access to lexical memory,and output speed

Rehearsal speed has traditionally been seen to be the prime determinant of individual differences in memory span. Recent studies, in the main using young children as the subject population, have suggested other contributors to span performance, notably contributions from long-term memory and forgetting and retrieval processes occurring during recall. In the current research we explore individual differences in span with respect to measures of rehearsal, output time, and access to lexical memory.We replicate standard short-term phenomena; we show that the variables that influence children's span performance influence adult performance in the same way; and we show that lexical memory access appears to be a more potent source of individual differences in span than either rehearsal speed or output factors.     

Transposed-letter and laterality effects in lexical decision

Two divided visual field lexical decision experiments were conducted to examine the role of the cerebral hemispheres in transposed-letter similarity effects. In Experiment 1, we created two types of nonwords: nonadjacent transposed-letter nonwords (TRADEGIA; the base word was TRAGEDIA, the Spanish for TRAGEDY) and two-letter different nonwords (orthographic controls: TRATEPIA). In Experiment 2, the controls were one-letter different nonwords (TRAGEPIA) instead of two-letter different nonwords (TRATEPIA). The effect of transposed-letter similarity was substantially greater in the right visual field (left hemisphere) than in the left visual field. Furthermore, nonwords created by transposing two letters were more competitive than the nonwords created by substituting one or two letters of a target word. We examine the implications of these findings for the models of visual word recognition.     

The time course of lemma retrieval in lexical decision tasks.

The time course of lemma retrieval was assessed in lexical decision tasks with semantic and syntactic priming using monomorphemic English nouns, verbs, and ambiguous word forms. The results showed distinct processing patterns associated with different syntactic categories. The findings suggest that among other factors lemma retrieval is affected by different types of constraints working on entity/event construal. The findings can be used to propose a view according to which a lemma represents an activation state triggered by a number of processing factors, such as conventionalized conceptual architecture of a lexical item and its relative activation threshold.     

The effects of bilateral presentations on lateralized lexical decision

We investigated how lateralized lexical decision is affected by the presence of distractors in the visual hemifield contralateral to the target. The study had three goals: first, to determine how the presence of a distractor (either a word or a pseudoword) affects visual field differences in the processing of the target; second, to identify the stage of the process in which the distractor is affecting the decision about the target; and third, to determine whether the interaction between the lexicality of the target and the lexicality of the distractor ("lexical redundancy effect") is due to facilitation or inhibition of lexical processing. Unilateral and bilateral trials were presented in separate blocks. Target stimuli were always underlined. Regarding our first goal, we found that bilateral presentations (a) increased the effect of visual hemifield of presentation (right visual field advantage) for words by slowing down the processing of word targets presented to the left visual field, and (b) produced an interaction between visual hemifield of presentation (VF) and target lexicality (TLex), which implies the use of different strategies by the two hemispheres in lexical processing. For our second goal of determining the processing stage that is affected by the distractor, we introduced a third condition in which targets were always accompanied by "perceptual" distractors consisting of sequences of the letter "x" (e.g., xxxx). Performance on these trials indicated that most of the interaction occurs during lexical access (after basic perceptual analysis but before response programming). Finally, a comparison between performance patterns on the trials containing perceptual and lexical distractors indicated that the lexical redundancy effect is mainly due to inhibition of word processing by pseudoword distractors.     

Inhibition of return in location- and identity-based choice decision tasks

Three experiments were conducted to determine whether inhibition of return can be best characterized as an attentional or a motor phenomenon. In the first experiment, subjects made choice key-press responses to the location of a target (left or right) or the identity of the target (X or +) by pressing a left or right response key. In the second experiment, the display was rotated 90° so that there was no direct spatial mapping between the vertically aligned stimulus display and the horizontally aligned response keys. In both experiments, inhibition of return was observed for location-based and identity-based choice responses, although more inhibition was seen in the identity-based responses. The results of the third experiment suggested that this larger inhibitory effect may be specific to the covert orienting of reflexive attention in response to the sudden appearance of a single peripheral stimulus in the identity tasks. Overall, the results are consistent with the attentional, not the motor, explanation of inhibition of return.     

Priming effects on lexical access and decision processes: A signal-detection analysis

Summary Signal-detection methodology was employed to examine the assumption that in a lexical-decision task context effects are primarily the result of post-access processes. Experiment 1, in which prime-relatedness was varied within subjects, found changes in target sensitivity (d) without corresponding changes in the response criterion. This outcome was interpreted as evidence that prior context facilitates lexical access, whereas post-access contributions remain constant across conditions. When prime-relatedness was varied between subjects in Experiment 2, the lexical-decision task showed differing context effects on access processes as well as on post-access processes. It was concluded that subjects adopt a single response criterion suited to maximize task performance. The particular response criterion adopted is a function of the stimulus set rather than a function of the relationship between prime and target on any single trial. Finally, it was concluded that post-access strategies alone are insufficient to account for context effects obtained when typical lexical-decision-task procedures are used, or to account for the magnitude of the differences obtained between the present experiments.