Modality effects in word identification

An experiment was designed to investigate the locus of persistence of information about presentation modality for verbal stimuli. Twenty-four Ss were presented with a continuous series of 672 letter sequences for word/nonword categorization. The sequences were divided equally between words and nonwords, and each item was presented twice in the series, either in the same or in a different modality. Repetition facilitation, the advantage resulting from a second presentation, was greatest in the intramodality conditions for both words (+re responses) and nonwords (?ve responses). Facilitation in these conditions declined from 170 msec at Lag 0 (4 sec) to approximately 40 msec at Lag 63. Facilitation was reduced in the cross-modality condition for words and was absent from the cross-modality condition for nonwords. The modality-specific component of the repetition effect found in the word/nonword categorization paradigm may be attributed to persistence in the nonlexical, as distinct from lexical, component of the word categorization process.     

False recognition following study of semantically related lists presented in jumbled word form

Three experiments explored a jumbled word effect in false recognition. Lists of theme-related items were presented in word or nonword form. Results indicated that critical lures semantically related to studied items were falsely recognised regardless of whether they were presented as words or nonwords. High false recognition rates to either SLEEP or SELEP following study of an appropriate theme list of items in nonword form should only occur if nonwords are recoded at study. With study conditions conducive to recoding, jumbled words induced false recognitions based on semantic associations among their respective base words. Disrupting a recoding process by creating "difficult" letter rearrangements for jumbled words (Experiment 2) appeared to eliminate the false recognition effect. In Experiment 3, presentation durations ranged from 110 ms to 880 ms. Although there was little evidence of a semantic false recognition effect at the fastest presentation rate, the brief durations appeared to be effective in eliminating the effect when items were studied in nonword form. These results appear to be consistent with an encoding activation/retrieval monitoring model.     

Sequential effects in the lexical decision task: The role of the item frequency of the previous trial

Two lexical decision experiments were conducted to determine whether there is a specific, localized influence of the item frequency of consecutive trials (i.e., first-order sequential effects) when the trials are not related to each other. Both low-frequency words and nonwords were influenced by the frequency of the precursor word (Experiment 1). In contrast, high-frequency words showed little sensitivity to the frequency of the precursor word (Experiment 2), although they showed longer reaction times for word trials preceded by a nonword trial. The presence of sequential effects in the lexical decision task suggests that participants shift their response criteria on a trial-by-trial basis.     

False recognition following study of semantically related lists presented in jumbled word form

Three experiments explored a jumbled word effect in false recognition. Lists of theme-related items were presented in word or nonword form. Results indicated that critical lures semantically related to studied items were falsely recognised regardless of whether they were presented as words or nonwords. High false recognition rates to either SLEEP or SELEP following study of an appropriate theme list of items in nonword form should only occur if nonwords are recoded at study. With study conditions conducive to recoding, jumbled words induced false recognitions based on semantic associations among their respective base words. Disrupting a recoding process by creating “difficult” letter rearrangements for jumbled words (Experiment 2) appeared to eliminate the false recognition effect. In Experiment 3, presentation durations ranged from 110 ms to 880 ms. Although there was little evidence of a semantic false recognition effect at the fastest presentation rate, the brief durations appeared to be effective in eliminating the effect when items were studied in nonword form. These results appear to be consistent with an encoding activation/retrieval monitoring model.     

Auditory event related potentials during lexical categorization in the oddball paradigm.

Event related potentials (ERPs) and reaction times (RTs) were recorded from 18 subjects, performing lexical categorization of words and nonwords. Three sets of monosyllable utterances, differentiated in semantic and rhyming attributes, were presented using the "oddball paradigm." ERPs included a sustained negativity which began approximately 100 msec after stimulus onset and peaked at approximately 400 mses (SN4) poststimulus, in response to target as well as to nontarget word stimuli. Semantic effects on SN4 latency were observed only for target utterances. Nonmeaningful word targets were associated with longer SN4 peak latencies as well as slower RTs compared to meaningful word targets. It is suggested that these longer latencies are due to a longer time required for an exhaustive search in permanent memory before categorizing a stimulus as a nonmeaningful word.     

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.     

Sequential dependencies in the lexical decision task

Two experiments addressed whether response latency in a trial of the lexical decision task is independent of the lexical status of the item presented in the previous trial. In Exp. 1, it was found that both word and nonword responses were significantly slower when the previous trial had involved a nonword than when it had involved a word. In Exp. 2, which employed a different list composition, it was found that responses to nonwords and pseudohomophones were significantly slower when the previous trial had involved a nonword or a pseudohomophone than when it had involved a word. However, responses to words were not influenced by the nature of the previous trial. We concluded that sequential dependencies exist across consecutive trials in the lexical decision task even when there is no semantic, morphological, phonological, or orthographic relationship between the items presented during those trials.     

Differential Effects of Number of Letters on Word and Nonword Naming Latency

The issue addressed in this study is whether there are differential effects of number of letters on word and nonword naming latency. Experiment 1 examined the effect of number of letters on latency for naming high-frequency words, low-frequency words, and nonwords. Number of letters affected latency for low-frequency words and nonwords but did not affect latency for high-frequency words. Number of letters was also negatively correlated with number of orthographic neighbours, number of friends, and average grapheme frequency. Number of letters continued to affect nonword naming latency, but not low-frequency word naming latency, after the effects of orthographic neighbourhood size, number of friends, and average grapheme frequency had been accounted for. Experiment 2 found that number of letters had no effect on the latency of delayed naming of the same words and nonwords. It is concluded that the effect of number of letters on nonword naming reflects a sequential, non-lexical reading mechanism.     

Effects of phonological similarity on priming in auditory lexical decision

Two auditory lexical decision experiments were conducted to determine whether facilitation can be obtained when a prime and a target share word-initial phonological information. Subjects responded “word” or “nonword” to monosyllabic words and nonwords controlled for frequency. Each target was preceded by the presentation of either a word or nonword prime that was identical to the target or shared three, two, or one phonemes from the beginning. The results showed that lexical decision times decreased when the prime and target were identical for both word and nonword targets. However, no facilitation was observed when the prime and target shared three, two, or one initial phonemes, These results were found when the interstimulus interval between the prime and target was 500 msec or 50 msec. In a second experiment, no differences were found between primes and targets that shared three, one, or zero phonemes, although facilitation was observed for identical prime-target pairs. The results are compared to recent findings obtained using a perceptual identification paradigm. Taken together, the findings suggest several important differences in the way lexical decision and perceptual identification tasks tap into the information-processing system during auditory word recognition.     

Does jugde activate COURT? Transposed-letter similarity effects in masked associative priming

Transposed-letter (TL) nonwords (e.g., jugde) can be easily misperceived as words, a fact that is somewhat inconsistent with the letter-position-coding schemes employed by most current models of visual word recognition. To examine this issue further, we conducted four masked semantic/associative priming experiments, using a lexical decision task. In Experiment 1, the related primes could be words, TL-internal nonwords, or replacement-letter (RL) nonwords (e.g., judge, jugde, or judpe, respectively; the target would be COURT). Relative to an unrelated condition, masked TL-internal primes produced a significant semantic/associative priming effect, an effect that was only slightly smaller than the priming effect for word primes. No effect, however, was observed for RL-nonword primes. In Experiment 2, the TL-nonword primes were created by switching the two final letters of the primes (e.g., judeg). The results again showed a semantic/associative priming effect for word primes, but not for TL-final nonword primes or for RL-nonword primes. Experiment 3 replicated the associative/semantic priming effect for TL-internal nonword primes, with, again, no effect for TL-final nonword primes. Finally, Experiment 4 again failed to yield a priming effect for TL-final nonword primes. The implications of these results for the choice of a letter-position-coding scheme in visual word recognition models are discussed.     

Context and lexical access: implications of nonword interference for lexical ambiguity resolution

To eliminate potential "backward" priming effects, Glucksberg, Kreuz, and Rho (1986) introduced a variant of the cross-modal lexical priming task in which subjects made lexical decisions to nonword targets that were modeled on a word related to either the contextually biased or unbiased sense of an ambiguous word. Lexical decisions to nonwords were longer than controls only when the nonword was related to the contextually biased sense of the ambiguous word, leading Glucksberg et al. to conclude that context does constrain lexical access and that the multiple access pattern observed in previous studies was probably an artifact of backward priming. We did not find nonword interference when the nonword targets used by Glucksberg et al. were preceded by semantically related ambiguous or unambiguous word primes. However, we did replicate their sentence context results when the ambiguous words were removed from the sentences. We conclude that the interference obtained by Glucksberg et al. is due to postlexical judgements of the congruence of the sentence context and the target, not to context constraining lexical access.     

Cortical evoked responses to synonyms and antonyms

The brain’s processing of synonymity and antonymy was explored by examining the cortical evoked responses to correct judgments that a test word was a synonym or an antonym of a standard word presented 1 sec previously. Each of five subjects judged 256 pairs of words in each of two sessions. The evoked response to the second word was averaged separately for synonym and antonym pairs. Presentation of each test word as a synonym or an antonym, the order of presentation of each pair, and the side of the “synonym” response key were counter-balanced within subjects. The difference between the averaged response to antonym test words and that to synonym test words differed biphasically over the interval 250-650 msec after the stimulus. The demonstration of an evoked response difference between synonyms and antnyms extends the applicability of evoked potentials from attributes of individual word meaning to the semantic relationships between words.     

Does temporal contiguity moderate contingency learning in a speeded performance task?

In four experiments, we varied the time between the onset of distracting nonwords and target colour words in a word–word version of the colour–word contingency learning paradigm. Contingencies were created by pairing a distractor nonword more often with one target colour word than with other colour words. A contingency effect corresponds to faster responses to the target colour word on high-contingency trials (i.e., distractor nonword followed by the target colour word with which it appears most often) than on low-contingency trials (i.e., distractor nonword followed by a target colour word with which it appears only occasionally). Roughly equivalent-sized contingency effects were found at stimulus-onset asynchronies (SOAs) of 50, 250, and 450 ms in Experiment 1, and 50, 500, and 1,000 ms in Experiment 2. In Experiment 3, a contingency effect was observed at SOAs of –50, –200, and –350 ms. In Experiment 4, interstimulus interval (ISI) was varied along with SOA, and learning was equivalent for 200-, 700-, and 1,200-ms SOAs. Together, these experiments suggest that the distracting stimulus does not need to be presented in close temporal contiguity with the response to induce learning. Relations to past research on causal judgement and implications for further contingency learning research are discussed.     

Does temporal contiguity moderate contingency learning in a speeded performance task?

In four experiments, we varied the time between the onset of distracting nonwords and target colour words in a word-word version of the colour-word contingency learning paradigm. Contingencies were created by pairing a distractor nonword more often with one target colour word than with other colour words. A contingency effect corresponds to faster responses to the target colour word on high-contingency trials (i.e., distractor nonword followed by the target colour word with which it appears most often) than on low-contingency trials (i.e., distractor nonword followed by a target colour word with which it appears only occasionally). Roughly equivalent-sized contingency effects were found at stimulus-onset asynchronies (SOAs) of 50, 250, and 450?ms in Experiment 1, and 50, 500, and 1,000?ms in Experiment 2. In Experiment 3, a contingency effect was observed at SOAs of -50, -200, and -350?ms. In Experiment 4, interstimulus interval (ISI) was varied along with SOA, and learning was equivalent for 200-, 700-, and 1,200-ms SOAs. Together, these experiments suggest that the distracting stimulus does not need to be presented in close temporal contiguity with the response to induce learning. Relations to past research on causal judgement and implications for further contingency learning research are discussed.     

Divided attention and prerecognition processing of spoken words and nonwords

Three recognition memory experiments examined phonemic similarity and false recognition under conditions of divided attention. The manipulation was presumed to have little effect on automatic, perceptual influences of memory. Prior research demonstrated that false recognition of a test word (e.g., discrepancy) was higher if the study list included a nonword derived from the future test word by changing a phoneme near the end of the item (e.g., discrepan/l/y) relative to an early phoneme change (e.g., /l/iscrepancy). The difference has been attributed to automatic, implicit activation of test words during prerecognition processing of related nonwords. Three experiments demonstrated that the late-change condition also contributed to higher false recognition rates with divided attention at encoding. Dividing attention disrupted recognition memory of studied words in Experiments 1 and 3. Results are discussed in terms of their relevance for an interpretation emphasizing the automatic, implicit activation of candidate words that occurs in the course of identifying spoken words and nonwords.     

This and THAP -- constraints on the pronunciation of new, written words

The pronunciation of nonwords that start with TH is investigated in lists and sentences. The initial phoneme is usually unvoiced (as in THOUGHT) when the nonword is embedded in lists of words and nonwords. In contrast, the initial phoneme is usually voiced (as in THIS) when such nonwords are read aloud in a function word position in a sentence. These findings are inconsistent with the current dual process theory of the routes from print to sound which implies that the phonology of a new word or nonword can be derived only from a form of letter-sound correspondence which is independent of lexical/syntactic pressures.     

Nonword naming: further exploration of the pseudohomophone effect in terms of orthographic neighborhood size, graphemic changes, spelling-sound consistency, and reader accuracy.

Five experiments examined nonword pronunciation. As reported by McCann and Besner (1987), accurate, regular pronunciations increased as the number of orthographic neighbors (N) increased. Adults read pseudohomophones (nonwords that sound like a word) more accurately than other nonwords only when the nonwords were low n, shared the consonants with the words on which they were based, and overall accuracy was lower. Children showed a pseudohomophone advantage even when N was high. Adults pronounced nonwords comprised of inconsistent endings (with existing regular and irregular pronunciations) in an irregular fashion when this resulted in a word; this applied to relatively high-N items.     

Lexical inhibition and sublexical facilitation are surprisingly long lasting

When a listener hears a word (beef), current theories of spoken word recognition posit the activation of both lexical (beef) and sublexical (/b/, /i/, /f/) representations. No lexical representation can be settled on for an unfamiliar utterance (peef). The authors examined the perception of nonwords (peef) as a function of words or nonwords heard 10-20 min earlier. In lexical decision, nonword recognition responses were delayed if a similar word had been heard earlier. In contrast, nonword processing was facilitated by the earlier presentation of a similar nonword (baff-paff). This pattern was observed for both word-initial (beef-peef), and word-final (job-jop) deviation. With the word-in-noise task, real word primes (beef) increased real word intrusions for the target nonword (peef), but only consonant-vowel (CV) or vowel-consonant (VC) intrusions were increased with similar pseudoword primes (baff-paff). The results across tasks and experiments support both a lexical neighborhood view of activation and sublexical representations based on chunks larger than individual phonemes (CV or VC sequences).     

Word matching and Lexical Decisions: A Visual Half-Field study

In unilateral Visual Half-Field tasks visuospatial and linguistic processing were compared. In a Word Matching task subjects judged the physical identity of simultaneously presented pairs of three-letter words or legal nonwords. No mainfield effects were found, but word pairs were recognized better and faster as "same" than nonword pairs. Latencies and errors in "different" pairs increased monotonically with position of letter change in the left but not in the right visual field (RVF), suggesting a serial, letter-by-letter way of processing for the right hemisphere and a whole word approach for the left. At this perceptual level the ability to store lexical information from the icon is stressed as a hemisphere-specific factor. In a Lexical Decision task the same subjects judged the same items on the word/nonword dimension. A RVF advantage associated with words as compared to nonwords occurred, as expected. Additional analysis suggests that order and difficulty of tasks may influence females' laterality, as compared to that of males.     

The word-detection effect: Sophisticated guessing or perceptual enhancement?

Subjects discriminate letters in words better than letters in nonwords. The sophisticated guessing hypothesis attributes this word advantage to a guessing strategy. In words, the possible letters at each letter position are constrained by letters at other positions, whereas letters in nonwords are not restricted in this manner. A critical test of this hypothesis is that if subjects are givenexplicit knowledge of the letters in nonwords before the trial, the word advantage would disappear. We investigated the effect of preknowledge of the alternatives in the word-detection effect. In the word-detection effect, subjects decide which of two character strings contains letters and which contains pseudoletters. In four experiments, subjects were more accurate with words than with nonwords, and subjects were more accurate when they were told the word or nonword before the trial. However, even with foreknowledge of the alternatives, subjects were more accurate with words than with nonwords.