Bigram Frequency,Number of Syllables and Morphemes and Their Effects on Lexical Decision and Word Naming

There has been an increasing volume of evidence supporting the role of the syllable in word processing tasks. Recently it has also been shown that orthographic redundancy, related to the pattern of bigram frequencies, could not explain the syllable number effect on lexical decision times. This was demonstrated on a large sample of words taken from the British Lexicon Project. In this study we extend this research by examining both lexical decision and word naming times taken from the English Lexicon Project . There was a syllable number effect for both tasks in the expected direction, and this effect was independent of the presence of a bigram trough. The research also examined the role of other bigram related variables and the number of morphemes on lexical decision and word naming times. The number of morphemes had a significant effect on both word processing tasks, with words with more morphemes producing faster reaction times and also fewer errors. This pattern was reversed for nonword lexical decision times. The results are discussed in the light of recent developments in models of reading.     

Lexical decision and the number of morphemes and affixes

There has been a considerable amount of research looking at the effects of both syllable number and syllable frequency on lexical decision and word naming times. Recently, there has also been an increased interest in morphological variables, but there have been no large scale studies that have examined the role of the number of morphemes in lexical decision for nonwords. This is partly because of the difficulty of identifying morphemes in nonwords. We present a program that identifies the presence of affixes and, therefore, can be used to count the number of morpheme‐like elements in a nonword. We then used the program to measure the importance of affixes/morphemes in predicting lexical decision in nonwords. The results suggested that morphemes have an important role in lexical decision for both words and nonwords.     

Do transposed-letter similarity effects occur at a syllable level?

One key issue for any computational model of visual word recognition is the choice of an input coding scheme for assigning letter position. Recent research has shown that transposed-letter similarity effects occur even when the transposed letters are not adjacent (caniso-casino; Perea & Lupker, 2004, JML). In the present study we conducted two single-presentation lexical decision experiments to examine whether transposed-letter effects occur at a syllable level. We tested two types of nonwords: (1) nonwords created by transposing two internal CV syllables (PRIVEMARA; the base word is primavera, the Spanish for spring) and (2) nonwords created by transposing two adjacent bigrams that do not form a syllable (PRIMERAVA). We also created the appropriate orthographic control conditions, in which the critical letters were replaced instead of being switched. Results showed that the transposition of two syllables or two adjacent bigrams produced a quite robust (and similar) transposed-letter effect. Thus, transposed-letter effects seem to occur at an early orthographic, graphemic level, rather than at a syllable level. We examine the implications of the observed results for the input coding schemes in visual word recognition.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh-PUNCH) than for high BF primes (e.g., panit-PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

Effects of subphonetic and syllable structure variation on word recognition

This study explored whether natural acoustic variations as exemplified by either subphonetic changes or syllable structure changes affect word recognition processes. Subphonetic variations were realized by differences in the voice-onset time (VOT) value of initial voiceless stop consonants, and syllable structure variations were realized by vowel deletion in initial unstressed syllables in multisyllable words. An auditory identity priming paradigm was used to determine whether the amount of facilitation obtained to a target stimulus in a lexical decision task was affected by the presence of these acoustic variations in a prime stimulus. Results revealed different patterns for the two types of variability as a function of lexical status. In the case of subphonetic variations, shortening of VOT resulted in reduced facilitation for words but not for nonwords, whereas in the case of syllable structure variation, vowel deletion in an unstressed syllable resulted in reduced facilitation for nonwords and increased facilitation for words. These findings indicate that subphonetic variability interferes with word recognition, whereas syllable structure variability does not, and that this effect is independent of the magnitude of the acoustic difference between a citation form and its variant. Furthermore, the results suggest that the lexical status of the target item plays a crucial role in the processing of both types of variability. Results are considered in relation to current models of word recognition.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh–PUNCH) than for high BF primes (e.g., panit–PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

Masked priming of words and nonwords in a naming task: Further evidence for a nonlexical basis for priming

Masked priming effects in word identification tasks such as lexical decision and word naming have been attributed to a lexical mechanism whereby the masked prime opens a lexical entry corresponding to the target word. Two experiments are reported in which masked repetition priming effects of similar magnitude were obtained with word and nonword targets in a naming task. Masked orthographic priming was more stable for word than for nonword targets, although morphological primes produced no advantage beyond that achieved by matched orthographic primes. These results, taken together with the recent finding that repetition priming of nonwords can be obtained in the lexical decision task, support the view that masked priming of words and nonwords has a nonlexical component. We suggest that masked primes can enhance target identification by contributing to the construction of an orthographic or a phonological representation of the target, regardless of the target's lexical status.     

Processing of Syllables in Production and Recognition Tasks

Empirical evidence for a functional role of syllables in visual word processing is abundant, however it remains rather heterogeneous. The present study aims to further specify the role of syllables and the cognitive accessibility of syllabic information in word processing. The first experiment compared performance across naming and lexical decision tasks by manipulating the number of syllables in words and non-words. Results showed a syllable number effect in both the naming task and the lexical decision task. The second experiment introduced a stimulus set consisting of isolated syllabic and non-syllabic trigrams. Syllable frequency was manipulated in a naming and in a decision task requiring participants to decide on the syllabic status of letter strings. Results showed faster responses for syllables than for non-syllables in both tasks. Syllable frequency effects were observed in the decision task. In summary, the results from these manipulations of different types of syllable information confirm an important role of syllabic units in both recognition and production.     

The nature of the syllabic neighbourhood effect in French

We investigated whether and how sublexical units such as phonological syllables mediate access to the lexicon in French visual word recognition. To do so, two lexical decision task (LDT) experiments examined the nature of the syllabic neighbourhood effect. In Experiments 1a and b, the number of higher frequency syllabic neighbours was manipulated while controlling for the first bigram. The results failed to show a pure syllabic neighbourhood effect. In Experiments 2a and b, syllabic neighbourhood and bigram frequency were factorially manipulated. The interaction showed that the syllabic neighbourhood effect was inhibitory when bigram frequency was high, whereas it was facilitatory when bigram frequency was low. Similar patterns of results were found in both the yes/no (Experiments 1a and 2a) and go/no-go LDTs (Experiments 1b and 2b), so varying task requirements of the lexical decision did not influence the effect. These findings are discussed in the context of parallel distributed processing and interactive-activation models, and suggest that orthographic redundancy properties contribute to the influence of phonological syllables.     

Picture–word interference reveals inhibitory effects of syllable frequency on lexical selection

While previous research has shown that high syllable frequency can facilitate speech production at the level of phonological/phonetic encoding, little is known about its influence on prephonological processes, specifically lexical selection. The current study used a picture–word interference (PWI) task to (a) shed light on the stages of lexical access where syllable frequency is relevant, and (b) inform as to whether lexical selection is accomplished via competition among activated word options. Participants named pictures whose names had high-frequency (HF) and low-frequency (LF) first syllables while ignoring phonologically related (same first syllable) or unrelated distractor words that were presented simultaneously. Word frequency was also manipulated, as half of the targets were HF words, and half were LF words. Results revealed inhibitory syllable frequency effects in all conditions, such that targets with HF first syllables were named more slowly than targets with LF first syllables. However, inhibitory syllable frequency effects were exacerbated in conditions thought to reflect heightened lexical competition, specifically in the presence of phonologically related distractors and for targets with low word frequency. These findings reveal novel evidence for first-syllable frequency effects on lexical selection and offer further support for models proposing delays at lexical selection due to activation of nontarget competitors.     

The syllable’s role in word naming

In a series of experiments, the masked priming paradigm with very brief prime exposures was used to investigate the role of the syllable in the production of English. Experiment 1 (word naming task) showed a syllable priming effect for English words with clear initial syllable boundaries (such as BALCONY), but no effect with ambisyllabic words targets (such as BALANCE, where the /l/ belongs to both the first and the second syllables). Experiment 2 failed to show such syllable priming effects in the lexical decision task. Experiment 3 demonstrated that for words with clear initial syllable boundaries, naming latencies were faster only when primes formed the first syllable of the target, in comparison with a neutral condition. Experiment 4 showed that the two possible initial syllables of ambisyllabic words facilitated word naming to the same extent, in comparison with the neutral condition. Finally, Experiment 5 demonstrated that the syllable priming effect obtained for CV words with clear initial syllable boundaries (such as DIVORCE) was not due to increased phonological and/or orthographic overlap. These results, showing that the syllable constitutes a unit of speech production in English, are discussed in relation to the model of phonological and phonetic encoding proposed by Levelt and Wheeldon (1994).     

The processing of lexical stress during visual word recognition: Typicality effects and orthographic correlates

Many studies that have examined reading at the single-word level have been restricted to the processing of monosyllabic stimuli, and, as a result, lexical stress has not been widely investigated. In the experiments reported here, we used disyllabic words and nonwords to investigate the processing of lexical stress during visual word recognition. In Experiments 1 and 2, we found an effect of stress typicality in naming and lexical decision. Typically stressed words (trochaic nouns and iambic verbs) elicited fewer errors than atypically stressed words (iambic nouns and trochaic verbs). In Experiment 3, we carried out an analysis of 340 word endings and found clear orthographic correlates of both grammatical category and lexical stress in word endings. In Experiment 4, we demonstrated that readers are sensitive to these cues in their processing of nonwords during two tasks: sentence construction and stress assignment. We discuss the implications of these findings with regard to psycholinguistic models of single-word reading.     

Typing letter strings varying in orthographic structure

Subjects typed six-letter strings varying in orthographic structure. Lexical status, word frequency, position-sensitive log bigram frequency, and regularity of letter sequencing were systematically varied. Cumulative reaction times (RTs) of the keystrokes were adequately described by a linear function of letter position in the test string. Overall, words were typed faster than nonwords, and regular strings faster than irregular strings. Although the effect of log bigram frequency was not significant, this variable interacted with regularity and word frequency. Post hoc analyses of performance on each of the 200 letter strings revealed significant effects of the number of irregularities, log bigram frequency, and log word frequency. Transition times between successive keystrokes were significantly longer for illegal than for legal letter transitions. These results are similar to previous findings on the role of orthographic structure in the perceptual recognition of letter strings and provide a more complete analysis of context effects in typing.     

Neighborhood Effects on Nonword Visual Processing in a Language with Shallow Orthography

Neighborhood size and neighborhood frequency were orthogonally varied in two experiments on Italian nonwords. In Experiment 1, an inhibitory effect of neighborhood frequency on visual lexical decision was found: The presence of one high-frequency neighbor increased response latencies and error rates to nonwords. By contrast, no effect of neighborhood size and no neighborhood size x neighborhood frequency interaction were found. In Experiment 2, a facilitatory effect of neighborhood size on nonword naming was shown: Naming latencies were faster when nonwords had a large neighborhood. In the naming experiment, there was no effect of neighbors' frequency and no neighborhood size x neighborhood frequency interaction. An additional role for bigram frequency was found whereas syllable frequency did not give any independent contribution. These results further corroborate the view that, in a language with transparent orthography like Italian, despite a substantial contribution of sublexical print-to-sound mapping due to the language's high regularity/consistency, reading aloud of nonlexical material may benefit from the contribution of the lexical component.     

The processing of lexical stress during visual word recognition: typicality effects and orthographic correlates

Many studies that have examined reading at the single-word level have been restricted to the processing of monosyllabic stimuli, and, as a result, lexical stress has not been widely investigated. In the experiments reported here, we used disyllabic words and nonwords to investigate the processing of lexical stress during visual word recognition. In Experiments 1 and 2, we found an effect of stress typicality in naming and lexical decision. Typically stressed words (trochaic nouns and iambic verbs) elicited fewer errors than atypically stressed words (iambic nouns and trochaic verbs). In Experiment 3, we carried out an analysis of 340 word endings and found clear orthographic correlates of both grammatical category and lexical stress in word endings. In Experiment 4, we demonstrated that readers are sensitive to these cues in their processing of nonwords during two tasks: sentence construction and stress assignment. We discuss the implications of these findings with regard to psycholinguistic models of single-word reading.     

Processing lexically embedded spoken words

A large number of multisyllabic words contain syllables that are themselves words. Previous research using cross-modal priming and word-spotting tasks suggests that embedded words may be activated when the carrier word is heard. To determine the effects of an embedded word on processing of the larger word, processing times for matched pairs of bisyllabic words were examined to contrast the effects of the presence or absence of embedded words in both 1st- and 2nd-syllable positions. Results from auditory lexical decision and single-word shadowing demonstrate that the presence of an embedded word in the 1st-syllable position speeds processing times for the carrier word. The presence of an embedded word in the 2nd syllable has no demonstrable effect.     

Processing variant forms in spoken word recognition: the role of variant frequency

Recognition of a spoken word phonological variant--schwa vowel deletion (e.g., corporate --> corp'rate)--was investigated in vowel detection (absent/present) and syllable number judgment (two or three syllables) tasks. Variant frequency corpus analyses (Patterson, LoCasto, & Connine, 2003) were used to select words with either high or low schwa vowel deletion rates. Speech continua were created for each word in which schwa vowel length was manipulated (unambiguous schwa-present and schwa-absent endpoints, along with intermediate ambiguous tokens). Matched control nonwords were created with identical schwa vowel continua and surrounding segments. The low-deletion-rate words showed more three-syllable judgments than did the high-deletion-rate words. Matched control nonwords did not differ as a function of deletion rate. Experiments 2 and 3 showed a lexical decision reaction time advantage for more frequent surface forms, as compared with infrequent ones, for schwa-deleted (Experiment 2) and schwa-present (Experiment 3) stimuli. The results are discussed in terms of representations of variant forms of words based on variant frequency.     

The effect of preview eccentricity in a lexical decision task

We report lexical decision experiments in which eye movements and lexical decision time were analysed. The results show that nonwords produced more fixation than words, and that the time to make a lexical decision was also greater for nonwords. Further, a preview of the stimulus was presented on some occasions either at fixation or peripherally. When the presentation was peripheral the number of refixations and lexical decision times were reduced. Parafoveal previews of words also reduced word length effects on refixations and lexical decision time. These effects decreased (for nonwords) when the case of the letters was changed in the preview. These results are compatible with the idea that the peripheral preview benefit derives from word visual structure in addition to information about word length, word envelope, and single letter identities.     

Type-based bigram frequencies for five-letter words.

Researchers often require subjects to make judgments that call upon their knowledge of the orthographic structure of English words. Such knowledge is relevant in experiments on, for example, reading, lexical decision, and anagram solution. One common measure of orthographic structure is the sum of the frequencies of consecutive bigrams in the word. Traditionally, researchers have relied on token-based norms of bigram frequencies. These norms confound bigram frequency with word frequency because each instance (i.e., token) of a particular word in a corpus of running text increments the frequencies of the bigrams that it contains. In this article, the authors report a set of type-based bigram frequencies in which each word (i.e., type) contributes only once, thereby unconfounding bigram frequency from word frequency. The authors show that type-based bigram frequency is a better predictor of the difficulty of anagram solution than is token-based frequency. These norms can be downloaded from www.psychonomic.org/archive/.     

For a psycholinguistic model of handwriting production: testing the syllable-bigram controversy

This study examined the theoretical controversy on the impact of syllables and bigrams in handwriting production. French children and adults wrote words on a digitizer so that we could collect data on the local, online processing of handwriting production. The words differed in the position of the lowest frequency bigram. In one condition, it coincided with the word's syllable boundary. In the other condition, it was located before the syllable boundary. The results yielded higher movement durations at the position where the low-frequency bigram coincided with the syllable boundary compared to where the low-frequency bigram appeared before the syllable boundary. Syllable-oriented strategies failed with the presence of a very low-frequency bigram within the initial syllable. Further analysis showed that children in grades 3 and 4 privileged syllable-oriented programming strategies. The production times of children in grade 4 were also affected by syllable frequency and, to a lesser extent, bigram frequency. The adults writing durations were modulated by bigram frequency. Therefore, both bigrams and syllables regulate handwriting production although the influence of bigrams was stronger in adults than children. In the light of these results, we propose a psycholinguistic model of handwriting production.