Using dictionaries to study the mental lexicon.

The notion of a mental lexicon has its historical roots in practical reference dictionaries. The distributional analysis of dictionaries provides one means of investigating the structure of the mental lexicon. We review our earlier work with dictionaries, based on a three-way horserace model of lexical access and production, and then present the most recent results of our ongoing analysis of the Oxford English Dictionary, Second Edition on CD-ROM, which traces changes in productivity over time of the English suffixes -ment and -ity, both of which originate in French borrowings. Our results lead us to question the validity of automatic analogy from a set of existing words as the driving force behind morphological productivity.     

Young children's sensitivity to probabilistic phonotactics in the developing lexicon

A series of three experiments examined children's sensitivity to probabilistic phonotactic structure as reflected in the relative frequencies with which speech sounds occur and co-occur in American English. Children, ages 212 and 312 years, participated in a nonword repetition task that examined their sensitivity to the frequency of individual phonetic segments and to the frequency of combinations of segments. After partialling out ease of articulation and lexical variables, both groups of children repeated higher phonotactic frequency nonwords more accurately than they did low phonotactic frequency nonwords, suggesting sensitivity to phoneme frequency. In addition, sensitivity to individual phonetic segments increased with age. Finally, older children, but not younger children, were sensitive to the frequency of larger (diphone) units. These results suggest not only that young children are sensitive to fine-grained acoustic-phonetic information in the developing lexicon but also that sensitivity to all aspects of the sound structure increases over development. Implications for the acoustic nature of both developing and mature lexical representations are discussed.     

Word lists for testing cognitive biases toward body shape among men and women

The present study developed word lists describing three categories of body build—fat, thin, and muscular— for use in investigating cognitive risk factors for body dissatisfaction. Fifty-one men and 51 women rated the categorization, valence, and familiarity of 284 body-related adjectives in order to develop the final lists. The normative frequency of each of the 284 words was determined using an index of American English. The final 19- to 26-item word lists were constructed so that the average number of syllables, word length, word frequency, and mean percentage of categorization agreement were comparable. The availability of these word lists will facilitate future cognitive research into a key risk factor for eating disorders.     

Cross-linguistic evidence for morphological representation in the mental lexicon.

Three types of naturally occurring data address the question of morphological structure in the lexical entry: code-switching, novel forms, and speech errors. The data were collected from a wide variety of languages, including Austro-Polynesian, Semitic, and Altaic languages, and a heretofore untapped set of affixation types, including infixes, circumfixes, multiple affixes, reduplication, and nonconcatenative morphology. The data are used to argue for a dual-listing model of lexical representation (e.g., Pinker, 1991; Frauenfelder & Schreuder, 1992) over full-listing (e.g., Butterworth, 1983) and fully parsed (e.g., Taft & Forster, 1975) models. The paper posits three morphological parameters which are activated language-specifically.     

Phonological abstraction in the mental lexicon

A perceptual learning experiment provides evidence that the mental lexicon cannot consist solely of detailed acoustic traces of recognition episodes. In a training lexical decision phase, listeners heard an ambiguous [f–s] fricative sound, replacing either [f] or [s] in words. In a test phase, listeners then made lexical decisions to visual targets following auditory primes. Critical materials were minimal pairs that could be a word with either [f] or [s] (cf. English knife–nice), none of which had been heard in training. Listeners interpreted the minimal pair words differently in the second phase according to the training received in the first phase. Therefore, lexically mediated retuning of phoneme perception not only influences categorical decisions about fricatives (Norris, McQueen, & Cutler, 2003), but also benefits recognition of words outside the training set. The observed generalization across words suggests that this retuning occurs prelexically. Therefore, lexical processing involves sublexical phonological abstraction, not only accumulation of acoustic episodes.     

From the lexicon to expectations about kinds: a role for associative learning

In the novel noun generalization task, 2 1/2-year-old children display generalized expectations about how solid and nonsolid things are named, extending names for never-before-encountered solids by shape and for never-before-encountered nonsolids by material. This distinction between solids and nonsolids has been interpreted in terms of an ontological distinction between objects and substances. Nine simulations and behavioral experiments tested the hypothesis that these expectations arise from the correlations characterizing early learned noun categories. In the simulation studies, connectionist networks were trained on noun vocabularies modeled after those of children. These networks formed generalized expectations about solids and nonsolids that match children's performances in the novel noun generalization task in the very different languages of English and Japanese. The simulations also generate new predictions supported by new experiments with children. Implications are discussed in terms of children's development of distinctions between kinds of categories and in terms of the nature of this knowledge.     

Mental lexicon research in the new millennium

This article presents an overview of current research on the mental lexicon, as it is represented by articles in the spring 2002 Special Issue of Brain and Language. We examine current findings in terms of language, task, and population effects associated with how words are presented and processed in the mind. We discuss how such mental representations may be linked to neurological instantiations and address the issue of ecological validity in the field. These discussions are organized in order to both provide an overview of the issues and to enable the reader to locate specific articles that bear on these issues. Finally, we present an organizational framework for the characterization of mental lexicon research within which challenges for advancement are isolated.     

Morphological units in the Arabic mental lexicon

Standard views of morphology in Modern Standard Arabic hold that surface word forms comprise at least two morphemes: a three-consonantal root conveying semantic meaning and a word pattern carrying syntactic information. An alternative account claims that semantic information is carried by a bi-consonantal morphological unit called the etymon. Accordingly, in the form [batara] the core meaning is carried not by the tri-consonantal root morpheme [btr] but by the etymon morpheme [b,t] which surfaces in other forms like [batta] "sever", [batala] "cut off" with the same meaning "cutting". Previous experimental research in Semitic languages has assumed the tri-consonantal root/word pattern approach. In cross-modal and masked priming experiments we ask whether the etymon, as a more fine-grained two-consonantal morphological unit, can yield the morphological priming effects typically obtained with tri-consonantal root morphemes. The results clearly show that two words sharing an etymon do facilitate each other both in cross-modal and masked priming even though they do not share a root, controlling for semantic and for form overlap effects. The bearing of these results on theories of morphological processing and representation is discussed.     

Word shape,orthographic regularity,and contextual interactions in a reading task

In an investigation of the interaction between three sources of information about a printed word, skilled readers performed a simple naming task. The naming latency was observed as a function of case of presentation, orthographic regularity, and the congruency of context supplied in a previously presented sentence. Differences between regular and irregular words were observed for upper case presentations only, suggesting that lexical access can proceed via a direct visual route only when the distinctive features of the global word envelope are available. Incongruent sentences inhibited word naming, and congruent sentences facilitated naming, but this effect was more apparent for upper case than for lower case words. These results suggest an interaction of information during word recognition, with the removal of the word envelope leading to a greater dependence upon other intrinsic and extrinsic information.     

Word length,phonemic, and visual similarity effects in poor and normal readers

Serial order recall for visually and auditorily presented stimuli was examined in a group of 12-year-old poor readers and 7-year-old reading-age controls. With pictorial presentation, the poor readers showed a visual similarity effect, no word length effect, and a smaller phonemic similarity effect than that of controls. However, with visual presentation of printed words and with auditory presentation, poor readers showed word length and phonemic similarity effects of similar magnitude to that of controls. It is concluded that poor readers rely on visual information in tasks where the presented images are highly codable, and where verbal recoding is not obligatory, but that they will make use of phonological coding when the stimuli are not as easily codable visually in memory.     

Patterns of acquisition in the emerging mental lexicon: the case of to and for in English.

A corpus analysis of 32 English-speaking children's first usages of the prepositions to and for (which have similar properties semantically and grammatically) was undertaken for the purpose of tracking intralexemic sense acquisition and lexical organization in an often neglected word class. The earliest senses used by these children do not reflect historical patterns of semantic extension. Diachronically, concrete, spatial, and semantically transparent usages emerged before more abstract, nonspatial, and opaque usages. Developmentally, frequency of use in the child's linguistic environment and co-occurrence in collocations with favored verbs or other useful expressions proved to be the major determinant of early production, suggesting that external rather than internal/cognitive factors play the major role in lexical development.     

Representation in the mental lexicon: Implications for theories of the generation effect

Three experiments investigated the finding by McElroy and Slamecka (1982) that the “generation effect” (the retention advantage for self-produced over read items) is not obtained when artificial, meaningless nonwords are used as the to-be-remembered items. In Experiment 1, some subjects were asked to generate or read items that they thought were words, but, in fact, were not; no generation effect was found. In Experiment 2, subjects were taught definitions to experimenter-created items. Despite the fact that these subjects could readily retrieve each item’s assigned semantic properties, no generation effect was found. Finally, Experiment 3 examined the read]generate variable as a function of an item’s frequency of use in the language. Whereas medium- and high-frequency words produced large generation effects, no comparable effects were found for low-frequency words or nonwords. These results indicate that representation in the mental lexicon is a necessary, but not a sufficient, condition for the generation effect. Rather, it may be necessary to consider how related the generated item is to other potential retrieval cues in the memory system.     

Phonological and form class relations in the lexicon

Two experiments were conducted to examine the structure of the mental lexicon. A lexical search of American English, using the Brown corpus (Francis and Kucera, 1982), revealed a skewed, frequency-dependent distribution in which the syntactic classes of noun and verb are distinguished in terms of the phonological classification of their vowels. Among high-frequency words, nouns are more likely to have back vowels (57%) rather than front vowels (43%) and verbs more likely to have front vowels (62%) than back vowels (38%). This distribution, however, does not hold for low-frequency nouns and verbs in the language. Noun and verb stimuli containing front and back vowels were examined in both an auditory noun/verb categorization task and an auditory lexical decision task. In general, the phonotactic composition of nouns and verbs in the lexicon was shown to have perceptual consequences. Listeners seem to be differentially sensitive to incoming sound patterns on the basis of distributional properties of the lexicon.These experiments were conducted at the Brown University Phonetics Laboratory. The technical expertise of John Mertus and Andrew Mackie as well as the help of Martha Burton and Annemie Witjes are gratefully acknowledged.     

Representation of inflected nouns in the internal lexicon

The lexical representation of Serbo-Croatian nouns was investigated in a lexical decision task. Because Serbo-Croatian nouns are declined, a noun may appear in one of several grammatical cases distinguished by the inflectional morpheme affixed to the base form. The grammatical cases occur with different frequencies, although some are visually and phonetically identical. When the frequencies of identical forms are compounded, the ordering of frequencies is not the same for masculine and feminine genders. These two genders are distinguished further by the fact that the base form for masculine nouns is an actual grammatical case, the nominative singular, whereas the base form for feminine nouns is an abstraction in that it cannot stand alone as an independent word. Exploiting these characteristics of the Serbo-Croatian language, we contrasted three views of how a noun is represented: (1) the independent-entries hypothesis, which assumes an independent representation for each grammatical case, reflecting its frequency of occurrence; (2) the derivational hypothesis, which assumes that only the base morpheme is stored, with the individual cases derived from separately stored inflectional morphemes and rules for combination; and (3) the satellite-entries hypothesis, which assumes that all cases are individually represented, with the nominative singular functioning as the nucleus and the embodiment of the noun’s frequency and around which the other cases cluster uniformly. The evidence strongly favors the satellite-entries hypothesis.     

Morphological priming in the German mental lexicon.

We present results from cross-modal priming experiments on German participles and noun plurals. The experiments produced parallel results for both inflectional systems. Regular inflection exhibits full priming whereas irregularly inflected word forms show only partial priming: after hearing regularly inflected words (-t participles and -s plurals), lexical decision times on morphologically related word forms (presented visually) were similar to reaction times for a base-line condition in which prime and target were identical, but significantly shorter than in a control condition where prime and target were unrelated. In contrast, prior presentation of irregular words (-n participles and -er plurals) led to significantly longer response times on morphologically related word forms than the prior presentation of the target itself. Hence, there are clear priming differences between regularly and irregularly inflected German words. We compare the findings on German with experimental results on regular and irregular inflection in English and Italian, and discuss theoretical implications for single versus dual-mechanism models of inflection.     

Common and modality-specific processes in the mental lexicon

Eight experiments were conducted to resolve: (1) empirical inconsistencies in repetition effects under intermodality conditions in word identification and lexical decision, and (2) an associated theoretical conflict concerning lexical organization. The results demonstrated that although more facilitation occurs under visual-prime/visual-test (VV) conditions than under auditory-prime/visual-test (AV) conditions, significant repetition facilitation also occurs under AV conditions. The results also indicated that: repetition effects observed for the VV and AV conditions apply to high- as well as to low-frequency words; they are insensitive to a variety of encoding tasks designed to emphasize different properties of words; and they are unaffected by differences in the ease of encoding of isolated auditory and visual words. The results are consistent with the existence of both modality-specific and common or modality-free processes in word recognition, in which word-frequency effects are restricted to the second and, by implication, lexical stage.     

Evidence for frequency-based constituents in the mental lexicon: collocations involving the word of

In this paper, it is hypothesized that units larger than the traditional word, such as two-word collocations and phrases, may be stored in the mental lexicon and accessed holistically. Following previously published work on the Network or Usage-based model of lexical storage (Bybee, 1985, 1995), we suggest that the mechanism determining this constituency is the frequency with which items occur together in natural, connected speech: the collocational frequency. The present study uses a word-monitoring paradigm to investigate reaction times to the English function word of in collocations of varying levels of frequency. A significant effect of collocational frequency was observed; response latencies were longer when the target word of occurred in the very frequent collocations, indicating holistic processing of the frequent phrases. Furthermore, response latencies presented here are considerably longer than those reported in previous studies. This is explained as a result of the hypothesized holistic representation as well as a function of the use of stimuli extracted from natural conversation.     

Semantic and phonological information flow in the production lexicon

When speakers produce words, lexical access proceeds through semantic and phonological levels of processing. If phonological processing begins based on partial semantic information, processing is cascaded; otherwise, it is discrete. In standard models of lexical access, semantically processed words exert phonological effects only if processing is cascaded. In 3 experiments, speakers named pictures of objects with homophone names (ball), while auditory distractor words were heard beginning 150 ms prior to picture onset. Distractors speeded picture naming (compared with controls) only when related to the nondepicted meaning of the picture (e.g., dance), exhibiting an early phonological effect, thereby supporting the cascaded prediction. Distractors slowed picture naming when categorically (e.g., frisbee) related to the depicted picture meaning, but not when associatively (e.g., game) related to it. An interactive activation model is presented.     

Visual and phonological pathways to the lexicon: Evidence from Chinese readers

In this study, we investigated the role of visual and phonological information in lexical access of Chinese characters. Homophonic English words have been the main source of stimuli for word recognition research. However, since these stimuli also often look alike, visual and phonological information may be confounded in reported experiments. In contrast, many homophonic Chinese characters are visually distinct. In addition, visually similar characters often have very different pronunciations. These characteristics allow a more controlled investigation of the roles of visual and phonological information in activation of meaning. In the present study, two types of Chinese characters were used in a semantic categorization paradigm: integrated characters, which contain strokes that are not separable; and compound characters, which contain at least two clearly identifiable components. The results show that the recognition of a Chinese integrated character depends primarily on visual information, whereas the recognition of a Chinese compound character relies on visual, phonological, and semantic information. It is concluded that visual information plays a greater role in Chinese character recognition than has previously been documented.