The basis of preference for lexical words in 6-month-old infants

Six-month-old English-learning infants have been shown to prefer English lexical over English grammatical words. The preference is striking because there are few grammatical words in total number but each occurs far more frequently in input speech than any individual lexical word. This could be because lexical words are universally more salient and interesting acoustic and phonological forms than are grammatical words. Alternatively, familiarity may play a role since infants may know some specific lexical words. Here we explore the first possibility by testing Chinese-learning infants’ response to English lexical and grammatical words. These infants, who had virtually no prior exposure to English and thus were unfamiliar with any English words, nevertheless preferred to listen to English lexical words, as in the case of English-learning infants. This finding increases the plausibility that it is the acoustic and phonological salience of lexical words that determines the preference for lexical words in infants.     

Newborn infants' sensitivity to perceptual cues to lexical and grammatical words.

In our study newborn infants were presented with lists of lexical and grammatical words prepared from natural maternal speech. The results show that newborns are able to categorically discriminate these sets of words based on a constellation of perceptual cues that distinguish them. This general ability to detect and categorically discriminate sets of words on the basis of multiple acoustic and phonological cues may provide a perceptual base that can help older infants bootstrap into the acquisition of grammatical categories and syntactic structure.     

The development of infants' preference for motherese

Generally, infants prefer infant-directed (ID) to adult-directed (AD) speech. Mostly, researchers have used unfamiliar female voices in these studies. We investigated preferences for maternal ID speech in 1- and 4-month-olds. Using a procedure in which infants controlled access to voices by fixating a visual display, infants listened to recordings of natural female ID and AD speech. In Experiment 1, 1-month-olds heard recordings of maternal ID and AD speech, but these infants showed no preference for maternal ID speech. In Experiment 2, 1-month-olds heard the same ID and AD speech tapes but were not familiar with the speakers. Contrary to Experiment 1, these infants preferred ID speech. In Experiment 3, 4-month-olds heard recordings of maternal ID and AD speech and showed a significant preference for ID speech. Collectively, these results suggest that infant attention to ID speech depends on both speaker-general and speaker-specific characteristics, with interesting developmental changes occuring during early infancy.     

Personality and lexical decision times for evaluative words

We studied personality influences on accessibility of pleasant and unpleasant stimuli in a sample of 129 students. Self‐reports and reports by knowledgeable informants on extraversion, neuroticism, approach temperament and avoidance temperament were combined with a go/no‐go lexical decision task that included pleasant, unpleasant and neutral words, and two response modes, manual and vocal. The data were analysed using multilevel modelling. Extraversion and approach temperament predicted faster identification of pleasant words than of neutral and of unpleasant words. Vocal responses took longer than manual responses, but mode of response did not interact with the valence of the words. Copyright © 2009 John Wiley & Sons, Ltd.     

Prenatal cocaine exposure and infants' preference for novelty and distractibility

The authors used the Fagan Test of Infant Intelligence (J. F. Fagan, L. T. Singer, J. E. Montie, & P. A. Shepherd, 1986) to examine preferences for novelty and to evaluate several indicators of attention (off- and on-task indexes and durations) in 6- and 9-month-old infants who had been prenatally exposed to cigarette smoke only or to cocaine plus other substances. The infants were matched for socioeconomic status. The authors found no group differences in preference for novelty, but the off-task distractibility index and duration were affected by exposure history and showed effects of dosage at the 9-month test time. Infants exposed to cocaine had a higher off-task index and a shorter average off-task look duration than did infants in the other groups. The authors interpreted this pattern of behavior as an indicator of distractibility or stimulation seeking. There were no group differences in measures involving on-task looks or duration at either test time. Correlations between the off-task look index and duration and teratogen use produced moderate correlations at 9 months of age. The authors calculated partial correlations between teratogen exposure and the off-task index at each trimester. Cocaine use during the 1st and 2nd trimesters was significantly correlated with the off-task index at 9 months of age, even when the authors controlled for neonatal measures (e.g., gestational age, birth weight) and during the 1st trimester when they controlled for alcohol and cigarette exposure.     

Understanding the referential nature of looking: infants' preference for object-directed gaze

In four experiments, we investigated whether 9-month-old infants are sensitive to the relationship between gaze direction and object location and whether this sensitivity depends on the presence of communicative cues like eye contact. Infants observed a face, which repeatedly shifted its eyes either toward, or away from, unpredictably appearing objects. We found that they looked longer at the face when the gaze shifts were congruent with the location of the object. A second experiment ruled out that this effect was simply due to spatial congruency, while a third and a fourth experiment revealed that a preceding period of eye contact is required to elicit the gaze-object congruency effect. These results indicate that infants at this age can encode eye direction in referential terms in the presence of communication cues and are biased to attend to scenes with object-directed gaze.     

Effects of lexical competition on immediate memory span for spoken words

Current theories and models of the structural organization of verbal short-term memory are primarily based on evidence obtained from manipulations of features inherent in the short-term traces of the presented stimuli, such as phonological similarity. In the present study, we investigated whether properties of the stimuli that are not inherent in the short-term traces of spoken words would affect performance in an immediate memory span task. We studied the lexical neighbourhood properties of the stimulus items, which are based on the structure and organization of words in the mental lexicon. The experiments manipulated lexical competition by varying the phonological neighbourhood structure (i.e., neighbourhood density and neighbourhood frequency) of the words on a test list while controlling for word frequency and intra-set phonological similarity (family size). Immediate memory span for spoken words was measured under repeated and nonrepeated sampling procedures. The results demonstrated that lexical competition only emerged when a nonrepeated sampling procedure was used and the participants had to access new words from their lexicons. These findings were not dependent on individual differences in short-term memory capacity. Additional results showed that the lexical competition effects did not interact with proactive interference. Analyses of error patterns indicated that item-type errors, but not positional errors, were influenced by the lexical attributes of the stimulus items. These results complement and extend previous findings that have argued for separate contributions of long-term knowledge and short-term memory rehearsal processes in immediate verbal serial recall tasks.     

Newly learned spoken words show long-term lexical competition effects

Newly learned spoken words (e.g., “cathedruke”) become fully engaged in the mental lexicon, as measured via lexical competition with their pre-existing phonological neighbours (e.g., “cathedral”), over the course of several hours or days, and this lexical restructuring is associated with sleep (Dumay & Gaskell, 2007). Here, we investigated the longer-term effects of word learning for three sets of novel words learned at different times using phoneme monitoring and repetition tasks. The effects of these exposure sessions on lexical memory were assessed in a battery of tests. Lexical decision latencies to pre-existing neighbouring words showed that lexical competition effects for the novel words remained observable 8 months after initial exposure. Furthermore, the order-of-acquisition of the novel words affected their production speed (but not recognition speed), with an advantage for earlier acquired words. The results suggest that the consolidation of novel words results in a long-term and stable change in the lexical competition process.     

Newly learned spoken words show long-term lexical competition effects

Newly learned spoken words (e.g., “cathedruke”) become fully engaged in the mental lexicon, as measured via lexical competition with their pre-existing phonological neighbours (e.g., “cathedral”), over the course of several hours or days, and this lexical restructuring is associated with sleep (Dumay & Gaskell, 2007). Here, we investigated the longer-term effects of word learning for three sets of novel words learned at different times using phoneme monitoring and repetition tasks. The effects of these exposure sessions on lexical memory were assessed in a battery of tests. Lexical decision latencies to pre-existing neighbouring words showed that lexical competition effects for the novel words remained observable 8 months after initial exposure. Furthermore, the order-of-acquisition of the novel words affected their production speed (but not recognition speed), with an advantage for earlier acquired words. The results suggest that the consolidation of novel words results in a long-term and stable change in the lexical competition process.     

Young infants encode lexical stress in newly encountered words

In this study, we examined the nature of infants’ representations of newly encountered word forms. Using a word–object association task, we taught 14-month-olds novel three-syllable words differing in segments and stress patterns. At test, we manipulated the stress pattern of the word or the position of the stressed syllable in the word. Our findings reveal that young infants store the stress information about the word, including the position in which the stressed syllable occurs, suggesting that infants form prosodically rich lexical representations of newly encountered words.     

Domain effects in lexical development: learning words for foods and toys

We investigated 3-year-olds’ and adults’ use of domain cues in learning words for solid and nonsolid material entities. In Experiments 1 and 2, participants heard a novel neutral noun (e.g., “my X”) for a standard solid or nonsolid entity described as either a toy or a food. They then were asked to extend the word to one of two other entities. Both options matched the standard in solidity; but one differed from it in an object-relevant property (shape) and the other in a substance-relevant property (color, texture, or smell). Both children and adults were more likely to select the same-shaped entity if the standard was (1) solid than if it was nonsolid, and (2) described as a toy than if it was described as a food. Their interpretations of novel words for material entities were thus affected not only by perceptual information (about solidity) but also by conceptual information (about domain). In Experiment 3, the novel noun was presented in a syntactic context that suggested the solid entity should be interpreted as an object (e.g., “an X”) and that the nonsolid entity should be interpreted as a substance (e.g., “some X”). For adults, these changes largely eliminated the effect of the entity’s domain (toy, food) on interpretation. We interpret these findings in terms of the proposal that domain cues, like solidity cues, furnish information about whether an entity’s structure should be thought of as arbitrary or nonarbitrary and, hence, about whether a word should be interpreted as naming an object or a substance construal.     

The influence of context on lexical decision times for emotionally aversive words

Forty-eight undergraduates made lexical decisions about emotionally aversive and nonemotional words. Emotionally aversive target words were preceded either by an emotionally aversive prime word, a nonemotional but semantically related prime or a nonemotional and semantically unrelated prime. Nonemotional targets were preceded by nonemotional primes which were either semantically related to targets, unrelated, or neutral (strings of Xs). Primes were presented for 50 ms to one group of 16 participants, 500 ms to a second group and 1250 ms to a third group. Measurement of lexical decision time showed significant semantic primary effects for nonemotional targets, and these were not influenced by prime duration. Priming effects for emotionally aversive targets due both to emotional and nonemotional relatedness of primes and targets were also found and these effects were not influenced by prime duration. The results are considered to be consistent with Bower’s (1981) associative network theory of memory, and possible clinical implications for explaining spontaneous panic attacks and the incubation of anxiety are discussed.     

Phonotactics, neighborhood activation, and lexical access for spoken words.

Probabilistic phonotactics refers to the relative frequencies of segments and sequences of segments in spoken words. Neighborhood density refers to the number of words that are phonologically similar to a given word. Despite a positive correlation between phonotactic probability and neighborhood density, nonsense words with high probability segments and sequences are responded to more quickly than nonsense words with low probability segments and sequences, whereas real words occurring in dense similarity neighborhoods are responded to more slowly than real words occurring in sparse similarity neighborhoods. This contradiction may be resolved by hypothesizing that effects of probabilistic phonotactics have a sublexical focus and that effects of similarity neighborhood density have a lexical focus. The implications of this hypothesis for models of spoken word recognition are discussed.     

Emotion words and categories: evidence from lexical decision

We examined the categorical nature of emotion word recognition. Positive, negative, and neutral words were presented in lexical decision tasks. Word frequency was additionally manipulated. In Experiment 1, “positive” and “negative” categories of words were implicitly indicated by the blocked design employed. A significant emotion–frequency interaction was obtained, replicating past research. While positive words consistently elicited faster responses than neutral words, only low frequency negative words demonstrated a similar advantage. In Experiments 2a and 2b, explicit categories (“positive,” “negative,” and “household” items) were specified to participants. Positive words again elicited faster responses than did neutral words. Responses to negative words, however, were no different than those to neutral words, regardless of their frequency. The overall pattern of effects indicates that positive words are always facilitated, frequency plays a greater role in the recognition of negative words, and a “negative” category represents a somewhat disparate set of emotions. These results support the notion that emotion word processing may be moderated by distinct systems.     

Right hemisphere advantage in lexical decision with two-character Chinese words

It has been suggested that the right hemisphere advantage reported in the literature for single Chinese or kanji characters is the result of perceptual factors rather than unique linguistic features of the orthography. However, no similar right hemisphere advantage for two-character words has ever been found. This study reports on a right hemisphere advantage for high stroke number low frequency two-character Chinese words with short exposure time and low luminance. While there is support for the perceptual-factors explanation for some findings of right hemisphere advantage for Chinese, it is suggested that linguistic factors can still play a part.     

The format of representation of recognized words in infants' early receptive lexicon

Eleven-month-olds can recognize a few auditorily presented familiar words in experimental situations where no hints are given by the intonation, the situation, or the presence of possible visual referents. That is, infants of this age (and possibly somewhat younger) can recognize words based on sound patterns alone. The issue addressed in this article is what is the type of mental representations infants use to code words they recognize. The results of a series of experiments with French-learning infants indicate that word representations in 11-month-olds are segmentally underspecified and suggest that they are all the more underspecified when infants engage in recognizing words rather than merely attending to meaningless speech sounds. But underspecification has limits, which were explored here with respect to word-initial consonants. The last two experiments show the way to investigating further these limits for word-initial consonants as well as for segments in other word positions. In French, infants' word representations are flexible enough to allow for structural changes in the voicing or even in the manner of articulation of word-initial consonants. Word-initial consonants must be present, however, for words to be recognized. In conclusion, a parallel is proposed between the emerging capacities to ignore variations that are irrelevant for word recognition in a “lexical mode” and to ignore variations that are phonemically irrelevant in a “neutral mode” of listening to native speech.     

The Malay Lexicon Project: A database of lexical statistics for 9,592 words

Malay, a language spoken by 250 million people, has a shallow alphabetic orthography, simple syllable structures, and transparent affixation—characteristics that contrast sharply with those of English. In the present article, we first compare the letter—phoneme and letter—syllable ratios for a sample of alphabetic orthographies to highlight the importance of separating language-specific from language-universal reading processes. Then, in order to develop a better understanding of word recognition in orthographies with more consistent mappings to phonology than English, we compiled a database of lexical variables (letter length, syllable length, phoneme length, morpheme length, word frequency, orthographic and phonological neighborhood sizes, and orthographic and phonological Levenshtein distances) for 9,592 Malay words. Separate hierarchical regression analyses for Malay and English revealed how the consistency of orthography—phonology mappings selectively modulates the effects of different lexical variables on lexical decision and speeded pronunciation performance. The database of lexical and behavioral measures for Malay is available at http://brm.psychonomic-journals.org/content/ supplemental.     

The role of subsyllabic structure in lexical access to printed words

Summary Three lexical-decision experiments investigated whether the subsyllabic structure of words is processed in the course of lexical access to printed words. Experiment 1 contrasted Italian words with same orthographic structure, but different subsyllabic structures. Latencies were shorter and error rates lower for words with a syllabic structure composed of fewer subsyllabic constituents. Experiment 2 ruled out the possibility that the results of Experiment 1 were due to differences in the frequency of bigrams composing the items. Bigram frequency had no effect on words of the same frequency as that of words in Experiment 1. Finally, Experiment 3 showed that it is not the number of subsyllabic constituents that affects lexical decision — rather the internal composition and frequency of the subsyllabic structure underlying a word. These results suggest that the subsyllabic structure of words is represented in abstract form in the mental lexicon and processed during lexical access. Subsyllabic structures, which are simpler and more common in the language, are more easily activated and processed, regardless of the number of subsyllabic constituents and the number of syllables composing the word.     

Lexical configuration and lexical engagement: When adults learn new words

People know thousands of words in their native language, and each of these words must be learned at some time in the person’s lifetime. A large number of these words will be learned when the person is an adult, reflecting the fact that the mental lexicon is continuously changing. We explore how new words get added to the mental lexicon, and provide empirical support for a theoretical distinction between what we call lexical configuration and lexical engagement. Lexical configuration is the set of factual knowledge associated with a word (e.g., the word’s sound, spelling, meaning, or syntactic role). Almost all previous research on word learning has focused on this aspect. However, it is also critical to understand the process by which a word becomes capable of lexical engagement—the ways in which a lexical entry dynamically interacts with other lexical entries, and with sublexical representations. For example, lexical entries compete with each other during word recognition (inhibition within the lexical level), and they also support the activation of their constituents (top-down lexical-phonemic facilitation, and lexically-based perceptual learning). We systematically vary the learning conditions for new words, and use separate measures of lexical configuration and engagement. Several surprising dissociations in behavior demonstrate the importance of the theoretical distinction between configuration and engagement.