Lila R. Gleitman

What some concepts might not be

A discussion of the difficulties of prototype theories for describing compositional meaning motivates three experiments that inquire how well-defined concepts fare under paradigms that are commonly interpreted to support the prototype view. The stimulus materials include exemplars of prototype categories (sport, vehicle, fruit, vegetable) previously studied by others, and also exemplars of supposedly well-defined categories (odd number, even number, female, and plane geometry figure). Experiment I, using these materials, replicated the exemplar rating experiment of Rosch (1973). It showed that both the well-defined and prototypic categories yield graded responses, the supposed hall-mark of a family resemblance structure. Experiment II, using the same sorts of stimulus materials, replicated a verification-time paradigm, also from Rosch (1973). Again, the finding was that both well-defined and prototypic categories yielded results previously interpreted to support a family-resemblance description of those categories, with faster verification times for prototypical exemplars of each category. In Experiment III, new subjects were asked outright whether membership in the category of fruit, odd number, etc., is a matter of degree, or is not, and then these subjects were rerun in the Experiment I paradigm. Though subjects judged odd number, etc., to be well-defined, they provided graded responses to all categories once again. These findings highlight interpretive difficulties for the experimental literature on this topic. Part I of the discussion first outlines a dual theory of concepts and their identification procedures that seems to organize these outcomes. But Part II of the discussion argues that feature theories are too impoverished to describe mental categories, in general.

The current status of the motherese hypothesis

Partially conflicting results from correlational studies of maternal speech style and its effects on child language learning motivate a comparative discussion of Newport, Gleitman & Gleitman (1977) and Furrow, Nelson & Benedict (1979), and a reanalysis of the original Newport et al. data. In the current analysis the data are from two groups of children equated for age, in response to the methodological questions raised by Furrow et al. ; but, in line with the original Newport et al. analysis, linguistic differences between these age-equated children are handled by partial correlation. Under this new analysis the original results reported by Newport et al. are reproduced. In addition, however, most effects of the mother on the childs language growth are found to be restricted to a very young age group. Moreover, the new analysis suggests that increased complexity of maternal speech is positively correlated with child language growth in this age range. The findings are discussed in terms of a theoretical analysis of the Motherese Hypothesis; the conditions of both learner and environment in which ‘simplified’ data could aid a learner. Finally, the results of our past work, those of Furrow et al. , and those of the present analysis, are discussed as they fit into, and add to, current theorizing about the language acquisition process.

When it is better to receive than to give: Syntactic and conceptual constraints on vocabulary growth

Abstract We ask how children solve the mapping problem for verb acquisition: how they pair concepts with their phonological realizations in their language. There is evidence that nouns but not verbs can be acquired by pairing each sound (e.g., ‘elephant’) with a concept inferred from the world circumstances in which that sound occurs. Verb meanings pose problems for this word-world mapping procedure, motivating a model of verb mapping mediated by attention to the syntactic structures in which verbs occur (Landau and Gleitman 1985, Gleitman 1990). We present an experiment examining the interaction between a conceptual influence (the bias to interpret observed situations as involving a casual agent) and syntactic influences, as these jointly contribute to childrens conjectures about new verb meanings. Children were shown scenes ambiguous as to two interpretations (e.g., giving and getting or chasing and fleeing ) and were asked to guess the meaning of novel verbs used to described the scenes, presented in varying syntactic contexts. Both conceptual and syntactic constraints influenced childrens responses, but syntactic information largely overwhelmed the conceptual bias. This finding, with collatoral evidence, supports a syntax-mediated procedure for verb acquisition.

On the semantic content of subcategorization frames

This paper investigates relations between the meanings of verbs and the syntactic structures in which they appear. This investigation is motivated by the enigmas as to how children discover verb meanings. Well-known problems with unconstrained induction of word meanings from observation of world circumstances suggest that additional constraints or sources of information are required. If there exist strong and reliable parallels between the structural and semantic properties of verbs, then an additional source of information about verb meanings is reliably present in each verbs linguistic context. Five experiments are presented which investigate the following hypothesis regarding the scope of these relations: The closer any two verbs in their semantic structure, the greater the overlap should be in their licensed syntactic structures. To investigate this hypothesis, data of two kinds were collected from different groups of subjects: (a) One group of subjects was asked to judge the semantic relatedness of verbs by selecting the semantic outlier in triads presented to them. (b) A second group of subjects was asked to judge the grammaticality of these same verbs in a large range of syntactic environments. These two types of data were then compared to assess the degree of correspondence in the two partitionings (syntactic and semantic) of the verb set. The findings, overall, support the view that the syntax of verbs is a quite regular, although complex, projection from their semantics. In conclusion, we discuss the kinds of features that are formally marked in syntactic structure and relate these to the problem of verb-vocabulary acquisition in young children.

The emergence of the child as grammarian

Abstract Demonstrations of some young childrens awareness of syntactic and semantic properties of language are presented. Rudiments of such ‘meta-linguistic’ functioning are shown in two-year olds, who give judgments of grammaticalness in a role-modelling situation. The growth of these abilities is documented for a group of five to eight-year old children, who are asked explicitly to give judgments of deviant sentences. Adult-like behavior, in these talented subjects, is found to emerge in the period from five to eight years. Possible relations of meta-linguistic functioning to other ‘meta-cognitive’ processes are suggested.

How words can and cannot be learned by observation.

Three experiments explored how words are learned from hearing them across contexts. Adults watched 40-s videotaped vignettes of parents uttering target words (in sentences) to their infants. Videos were muted except for a beep or nonsense word inserted where each “mystery word” was uttered. Participants were to identify the word. Exp. 1 demonstrated that most (90%) of these natural learning instances are quite uninformative, whereas a small minority (7%) are highly informative, as indexed by participants’ identification accuracy. Preschoolers showed similar information sensitivity in a shorter experimental version. Two further experiments explored how cross-situational information helps, by manipulating the serial ordering of highly informative vignettes in five contexts. Response patterns revealed a learning procedure in which only a single meaning is hypothesized and retained across learning instances, unless disconfirmed. Neither alternative hypothesized meanings nor details of past learning situations were retained. These findings challenge current models of cross-situational learning which assert that multiple meaning hypotheses are stored and cross-tabulated via statistical procedures. Learners appear to use a one-trial “fast-mapping” procedure, even under conditions of referential uncertainty.

Quality of early parent input predicts child vocabulary 3 years later

Children vary greatly in the number of words they know when they enter school, a major factor influencing subsequent school and workplace success. This variability is partially explained by the differential quantity of parental speech to preschoolers. However, the contexts in which young learners hear new words are also likely to vary in referential transparency; that is, in how clearly word meaning can be inferred from the immediate extralinguistic context, an aspect of input quality. To examine this aspect, we asked 218 adult participants to guess 50 parents’ words from (muted) videos of their interactions with their 14- to 18-mo-old children. We found systematic differences in how easily individual parents’ words could be identified purely from this socio-visual context. Differences in this kind of input quality correlated with the size of the children’s vocabulary 3 y later, even after controlling for differences in input quantity. Although input quantity differed as a function of socioeconomic status, input quality (as here measured) did not, suggesting that the quality of nonverbal cues to word meaning that parents offer to their children is an individual matter, widely distributed across the population of parents.

The Acquisition of the lexicon

The nature of the mental lexicon, Edwin Williams and Beth Levin discovering the word units, Anne Cutler et al categorizing the world, Susan Carey and Frank C. Keil categories, words and language, Ellen M. Markman et al the case of verbs, Cynthia Fischer, D. Geoffrey Hall et al procedures for verb learning, Michael R. Brent et al.

What Did the Brain Say to the Mind? A Study of the Detection and Report of Ambiguity by Young Children

Verbal humor is very much a part of everyday life, so it is not surprising that even young children laugh at riddles and jokes. They also invent their own, but these are perplexing. Here is an example from a five-year old of our acquaintance: Child: What has a trunk and four wheels? Us: I don’t know. What has a trunk and four wheels? Child: A car! (hilarious laughter) Despite manifest facility with the riddle format, this child apparently is unaware that riddles, at least good riddles, turn on linguistic ambiguity. At the same time, it is easy to show that children of this age are in perceptual and productive control of two senses for a single word (e.g., the two meanings of bark or club) or constructions (e.g., the two meanings of flying planes). This is one of many instances where children display competence in speech and understanding, but fail when the task is to see through to the linguistic event itself, manipulating it in the service of providing a judgment. Briefly, while the youngster is sensitive to potential alternate interpretations of speech signals, he cannot answer to the fact that some single speech event can be interpreted in two ways. He cannot give judgments concerning ambiguity.

Use of Speaker's Gaze and Syntax in Verb Learning.

Speaker eye gaze and gesture are known to help child and adult listeners establish communicative alignment and learn object labels. Here we consider how learners use these cues, along with linguistic information, to acquire abstract relational verbs. Test items were perspective verb pairs (e.g., chase/flee, win/lose), which pose a special problem for observational accounts of word learning because their situational contexts overlap very closely; the learner must infer the speakers chosen perspective on the event. Two cues to the speakers perspective on a depicted event were compared and combined: (a) the speakers eye gaze to an event participant (e.g., looking at the Chaser vs. looking at the Flee-er) and (b) the speakers linguistic choice of which event participant occupies Subject position in his utterance. Participants (3-, 4-, and 5-year-olds) were eye-tracked as they watched a series of videos of a man describing drawings of perspective events (e.g., a rabbit chasing an elephant). The speaker looked at one of the two characters and then uttered either an utterance that was referentially uninformative (Hes mooping him) or informative (The rabbits mooping the elephant/The elephants mooping the rabbit) because of the syntactic positioning of the nouns. Eye-tracking results showed that all participants regardless of age followed the speakers gaze in both uninformative and informative contexts. However, verb-meaning choices were responsive to speakers gaze direction only in the linguistically uninformative condition. In the presence of a linguistically informative context, effects of speaker gaze on meaning were minimal for the youngest children to nonexistent for the older populations. Thus children, like adults, can use multiple cues to inform verb-meaning choice but rapidly learn that the syntactic positioning of referring expressions is an especially informative source of evidence for these decisions.