Contrasting effects of age of acquisition in lexical decision and letter detection

Two experiments studied attention in beginning and skilled readers of Dutch to letter information in function words and content words. Early and late acquired nouns and function words were presented to third-grade students and skilled adolescent readers. Target words were presented in short story contexts, as in the study of Greenberg, Koriat, and Vellutino (1998). Target nouns were matched on word frequency. Predictions of the structural account hypothesis of letter detection (Koriat, Greenberg, & Goldshmid, 1991) were confirmed. No age-of-acquisition effect was found. In contrast, a separately conducted lexical decision experiment using the same content word stimulus sets showed shorter decision latencies for early acquired words. The combined results suggest that during silent reading, when attention is focused on meaning, phonological processes may play a less prominent role than in lexical decision tasks that demand explicit control of phonological codes. The letter detection results confirmed predictions of the structural account hypothesis for both beginning and skilled readers. Taken together, these studies demonstrate that phonological processes in silent reading may play a less prominent role and that the structural account of letter processing is valid for languages other than Hebrew and English but probably is not the unique mechanism involved in letter detection.     

Phonological ambiguity and lexical ambiguity: effects on visual and auditory word recognition

Three experiments in Serbo-Croatian were conducted on the effects of phonological ambiguity and lexical ambiguity on printed word recognition. Subjects decided rapidly if a printed and a spoken word matched or not. Printed words were either phonologically ambiguous (two possible pronunciations) or unambiguous. If phonologically ambiguous, either both pronunciations were real words or only one was, the other being a nonword. Spoken words were necessarily unambiguous. Half the spoken words were auditorily degraded. In addition, the relative onsets of speech and print were varied. Speed of matching print to speech was slowed by phonological ambiguity, and the effect was amplified when the stimulus was also lexically ambiguous. Auditory degradation did not interact with print ambiguity, suggesting that perception of the spoken word was independent of the printed word.     

The distinct contributions of age of acquisition and word frequency in auditory word perception

We report two studies of the distinct effects that a word's age of acquisition (AoA) and frequency have on the mental lexicon. In the first study, a purely statistical analysis, we show that AoA and frequency are related in different ways to the phonological form and imageability of different words. In the second study, three groups of participants (34 seven-year-olds, 30 ten-year-olds, and 17 adults) took part in an auditory lexical decision task, with stimuli varying in AoA, frequency, length, neighbourhood density, and imageability. The principal result is that the influence of these different variables changes as a function of AoA: Neighbourhood density effects are apparent for early and late AoA words, but not for intermediate AoA, whereas imageability effects are apparent for intermediate AoA words but not for early or late AoA. These results are discussed from the perspective that AoA affects a word's representation, but frequency affects processing biases.     

The distinct contributions of age of acquisition and word frequency in auditory word perception

We report two studies of the distinct effects that a word's age of acquisition (AoA) and frequency have on the mental lexicon. In the first study, a purely statistical analysis, we show that AoA and frequency are related in different ways to the phonological form and imageability of different words. In the second study, three groups of participants (34 seven-year-olds, 30 ten-year-olds, and 17 adults) took part in an auditory lexical decision task, with stimuli varying in AoA, frequency, length, neighbourhood density, and imageability. The principal result is that the influence of these different variables changes as a function of AoA: Neighbourhood density effects are apparent for early and late AoA words, but not for intermediate AoA, whereas imageability effects are apparent for intermediate AoA words but not for early or late AoA. These results are discussed from the perspective that AoA affects a word's representation, but frequency affects processing biases.     

Neighborhood frequency effects in visual word recognition: a comparison of lexical decision and masked identification latencies

Recent research suggests that the time to recognize a visually presented word may be a function of the frequencies of orthographically similar words. More precisely, recognition latencies and errors appear to increase significantly as soon as the stimulus word is orthographically similar to at least one other higher frequency word. This phenomenon, referred to as the neighborhood frequency effect, was subjected to further experimental testing, using a larger selection of words of varying frequency and length, and using a new experimental technique that proved to be extremely sensitive to such effects. The results provide additional support for earlier observations of neighborhood frequency effects. It is also demonstrated that clear word-frequency effects do obtain when neighborhood frequency is held constant. The results support activation-based accounts of the word-recognition process.     

Word-context effects in word naming and lexical decision

Stanovich and West (1983; West and Stanovich, 1982) demonstrated that lexical decisions to target words preceded by incongruous sentence contexts are inhibited more by these contexts than are naming responses to the same target words. They argued that this difference between the two tasks was due to post-lexical processing at the message level that is effective only in the lexical-decision task. The operations of the mechanism thought to underlie this post-lexical effect also predict that, under certain circumstances, the processing of target words congruous with the sentence context should be facilitated more in lexical decision than in naming. The present naming study together with an earlier lexical-decision study tested and confirmed this prediction for word targets following word contexts. The stimulus-onset asynchrony of context word and target word was also varied. This manipulation clearly affected the magnitude of facilitation, indicating that context-induced attentional processing can facilitate lexical access in word-context studies.     

Determinants of lexical access in speech production: Role of word frequency and age of acquisition

The main determinants of lexical access in speech are considered to be a word's age of acquisition (AoA) and its frequency of occurrence in a speaker's experience. It is unclear whether and how these variables interact, although they are commonly observed to be correlated, for the few studies that address the issue have reported inconsistent findings. An influential view of AoA in lexical processing (Ellis and Lambon Ralph, 2000) predicts stronger frequency effects for items acquired later in life than for those acquired at an early age. Five experiments were designed to investigate the possible interaction of AoA and frequency effects in speech. We found that the interaction between word frequency and AoA was not robust and that, contrary to expectation, the effect of word frequency was greater for words acquired earlier in life than for those acquired later. The implications of our findings are discussed.     

Age of acquisition, word frequency, and the role of phonology in the lexical decision task

In five experiments, we examined the respective roles of word age of acquisition (AoA) and frequency in the lexical decision task. The two variables were manipulated orthogonally (while controlling for concreteness and length) in fully factorial designs. Experiment 1 was a conventional lexical decision task, and Experiments 2-5 involved various attempts to interfere with reliance upon phonology. In Experiment 2, only orthographically illegal nonwords were used; in Experiment 3, pseudohomophone nonwords; in Experiment 4, articulatory suppression by the recitation of a nursery rhyme; and in Experiment 5, articulatory suppression by the repetition of a single word. The same basic pattern of results was observed in all experiments: There were main effects of both AoA and frequency, which interacted in such a way that the AoA effect was larger for low- than for high-frequency words. Although the AoA effect was reduced by manipulations intended to interfere with phonological processing, the manipulations did not eliminate the effect. The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.     

Additive and interactive effects of word frequency and masked repetition in the lexical decision task

In previous studies, additive effects of masked repetition and word frequency on lexical decision latency have been reported. This additive pattern was replicated in Experiment 1 with the use of lowfrequency words (range, 1–7 per million) selected at random. In contrast, in Experiment 2, in which low-frequency words known to be familiar to the subjects were used, the masked repetition priming effect was greater for low-frequency than for high-frequency words. It is suggested that the absence of an interaction between masked repetition and frequency observed in previous studies and in the present Experiment 1 was due to the fact that very-low-frequency words often have an unstable representation in the subjects’ lexicon and, consequently, sometimes fail to produce repetition priming effects in full.     

Cognitive effort and the word frequency effect in recognition and lexical decision

Cognitive effort requirements for high and low frequency words were assessed during study for a recognition test and during the performance of a lexical decision task. Recognition for these words was tested following each task. Low frequency words received greater effort than high frequency words during study for recognition, and these words were subsequently recognized better than high frequency words. Cognitive effort requirements during performance of an incidental lexical decision task were similar to those during study for recognition. Moreover, recognition performance following the lexical decision task resembled performance following a recognition expectancy. Overall, the results indicate that low frequency words require more extensive processing than high frequency words and that this difference in processing may be a factor in recognition word frequency effects.     

Aphasic performance on a lexical decision task: multiple meanings and word frequency

The lexical access of words varying in the number of meanings and frequency of occurrence was examined in fluent and nonfluent aphasic individuals and a control group of non-brain-damaged adults, using a lexical decision task. Fluent aphasic subjects performed similarly to nonfluent aphasic and normal subjects, showing that words with a high number of meanings and with a high frequency of occurrence were recognized as real words faster than words with few meanings or a low frequency of occurrence. While previous research has demonstrated that the number of meanings associated with a word exerts a powerful influence on the internal lexicon of normals, the results of this study suggest that brain damage resulting in aphasia does not disrupt this semantic organization.     

Hemispheric specialization for word classes with visual presentations and lexical decision task

In the present paper we study the possible RH capabilities for the processing of adjectives and verbs of high frequency and medium imagery using a lexical decision task and a horizontal display. In the analysis of both RTs and mean errors, a RVF advantage is obtained. The interaction VF x Word Class did not reach significance. Therefore, we did not find evidence of differences in the visual-field effect for any syntactic class. These results support a LH superiority for the processing of both adjectives and verbs. For the nonword conditions (pseudoverbs and pseudoadjectives), no visual field differences were observed in either group. Methodological aspects are also discussed.     

Word familiarity and frequency in visual and auditory word recognition

Four experiments investigate printed word frequency and subjective rated familiarity. Words of varied printed frequency and subjective familiarity were presented. A reaction time advantage for high-familiarity and high-frequency words was found in visual (Experiment 1) and auditory (Experiment 2) lexical decision. In Experiments 3 and 4, a cued naming task elicited a naming response after a specified delay after presentation. In Experiment 3, naming of visual words showed a frequency effect with no naming delay. The frequency effect diminished at longer delay intervals. Naming times for auditorily presented words (Experiment 4) showed no frequency effect at any delay. Both naming experiments showed familiarity effects. The relevance of these results are discussed in terms of the role of printed frequency for theories of lexical access, task- and modality-specific effects, and the nature of subjective familiarity.     

Semantic context and word frequency effects in visual word recognition

Semantic context and word frequency factors exert a strong influence on the time that it takes subjects to recognize words. Some of the explanations that have been offered for the effects of the two factors suggest that context and frequency should interact, and other explanations imply additivity. In a recent study, Schuberth and Eimas reported that context and frequency effects added to determine their subjects' reaction times in a lexical decision (word vs. nonword) task. The present experiment reexamines this question with improved procedures. The data show that context and frequency do interact, with a semantic context facilitating the processing of low-frequency words more than high-frequency words.     

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.     

Contextual diversity, not word frequency, determines word-naming and lexical decision times

Word frequency is an important predictor of word-naming and lexical decision times. It is, however, confounded with contextual diversity, the number of contexts in which a word has been seen. In a study using a normative, corpus-based measure of contextual diversity, word-frequency effects were eliminated when effects of contextual diversity were taken into account (but not vice versa) across three naming and three lexical decision data sets; the same pattern of results was obtained regardless of which of three corpora was used to derive the frequency and contextual-diversity values. The results are incompatible with existing models of visual word recognition, which attribute frequency effects directly to frequency, and are particularly problematic for accounts in which frequency effects reflect learning. We argue that the results reflect the importance of likely need in memory processes, and that the continuity between reading and memory suggests using principles from memory research to inform theories of reading.     

Effects of word frequency and age of acquisition on short-term memory span

The experiments reported examine the effects of two highly related variables, word frequency and age of acquisition, on short-term memory span. Short-term memory span and speech rate were measured for sets of words which independently manipulated frequency and age of acquisition. It was found that frequency had a considerable effect on short-term memory span, which was not mediated by speech rate differences—although frequency did affect speech rate in one experiment. For age of acquisition, this situation was reversed; there was a small but significant effect of age of acquisition on speech rate, but no effect on memory span. This occurred despite results confirming that the stimuli used in the experiments produce an effect of age of acquisition on word naming. The results are discussed in terms of a two-component view of performance on short-term memory tasks.     

The word frequency effect in lexical decision: Finding a frequency-based component

Subjects making lexical decisions are reliably faster in responding to high-frequency words than to low-frequency words. This is known as the word frequency effect. We wished to demonstrate that some portion of this effect was due to frequency differences between words rather than to other dimensions correlated with word frequency. Three groups of subjects (10 engineers, 10 nurses, and I0 law students) made lexical decisions about 720 items, half words and half nonwords, from six different categories (engineering, medical, low-frequency nontechnical, medium-frequency nontechnical, and two groups of high-frequency nontechnical). Results of two analyses of variance revealed a crossover interaction such that engineers were faster in responding to engineering words than to medical words, whereas nurses were faster in responding to medical words than to engineering words. The engineering and medical words were equally long and equally infrequent by standard word counts. We take this as support for a frequency-based component in the word frequency effect. The practical implications of this research for estimating the readability of technical text are discussed.     

Educational level and the word frequency effect: a lexical decision investigation.

It is known that speed and accuracy in recognizing words are constrained by the frequency of occurrence of these words ("frequency effect"). This study examines the relationship between educational level and the word frequency effect. We postulated that individual exposure to words that are rated lower in frequency tables should be greater among subjects with higher education and therefore hypothesized that the magnitude of the frequency effect should not be as marked within such a population as among subjects with a lesser educational level. A total of 40 neurologically healthy adults, half with an average of 18 years of formal education and the other half with an average of 11 years, participated in a lexical decision experiment. Results confirmed our hypothesis; that is, significant frequency effects on reaction times were obtained in both groups but this effect was of greater magnitude for the less educated as opposed to the more educated subgroup. The significance of this finding is discussed by reference to current models of word recognition.     

Effects of word frequency and spelling-to-sound regularity in naming with and without preceding lexical decision

The effects of word frequency and spelling-to-sound regularity were examined using standard naming, standard lexical-decision, go/no-go naming, and go/no-go lexical-decision tasks. In both the standard and go/no-go naming tasks, tasks requiring phonological coding, a significant Frequency x Regularity interaction was observed. That is, the regularity effect was limited to low-frequency words. In the standard and go/no-go lexical-decision tasks, tasks not requiring phonological coding, no Frequency x Regularity interaction was observed. These results indicate not only that the Frequency x Regularity interaction is a product of phonological coding processes but also that these processes are similar in the standard and go/no-go naming tasks. Results are discussed in terms of the dual-route and the parallel distributed processing frameworks.