Publications

Abstract

The topic of this paper is the way in which speakers order information in discourse. I will refer to this issue with the term "linearization", and will begin with two types of general remarks. The first one concerns the scope and relevance of the problem with reference to some existing literature. The second set of general remarks will be about the place of linearization in a theory of the speaker. The following, and main part of this paper, will be a summary report of research of linearization in a limited, but well-defined domain of discourse, namely the description of spatial networks.

Abstract

It is argued that the dominantly successive nature of language is largely mode-independent and holds equally for sign and for spoken language. A preliminary distinction is made between what is simultaneous or successive in the signal, and what is in the process; these need not coincide, and it is the successiveness of the process that is at stake. It is then discussed extensively for the word/sign level, and in a more preliminary fashion for the clause and discourse level that online processes are parallel in that they can simultaneously draw on various sources of knowledge (syntactic, semantic, pragmatic), but successive in that they can work at the interpretation of only one unit at a time. This seems to hold for both sign and spoken language. In the final section, conjectures are made about possible evolutionary explanations for these properties of language processing.

Abstract

In recent decades, psychologists have become increasingly interested in our ability to speak. This paper sketches the present theoretical perspective on this most complex skill of homo sapiens. The generation of fluent speech is based on the interaction of various processing components. These mechanisms are highly specialized, dedicated to performing specific subroutines, such as retrieving appropriate words, generating morpho-syntactic structure, computing the phonological target shape of syllables, words, phrases and whole utterances, and creating and executing articulatory programmes. As in any complex skill, there is a self-monitoring mechanism that checks the output. These component processes are targets of increasingly sophisticated experimental research, of which this paper presents a few salient examples.

Abstract

In this article, we present an account of developmental data regarding the acquisition of syllable types. The data come from a longitudinal corpus of phonetically transcribed speech of 12 children acquiring Dutch as their first language. A developmental order of acquisition of syllable types was deduced by aligning the syllabified data on a Guttman scale. This order could be analyzed as following from an initial ranking and subsequent rerankings in the grammar of the structural constraints ONSET, NO-CODA, *COMPLEX-O, and *COMPLEX-C; some local conjunctions of these constraints; and a faithfulness constraint FAITH. The syllable type frequencies in the speech surrounding the language learner are also considered. An interesting correlation is found between the frequencies and the order of development of the different syllable types.

Abstract

Speakers tend to repeat materials from previous talk. This tendency is experimentally established and manipulated in various question-answering situations. It is shown that a question's surface form can affect the format of the answer given, even if this form has little semantic or conversational consequence, as in the pair Q: (At) what time do you close. A: “(At)five o'clock.” Answerers tend to match the utterance to the prepositional (nonprepositional) form of the question. This “correspondence effect” may diminish or disappear when, following the question, additional verbal material is presented to the answerer. The experiments show that neither the articulatory buffer nor long-term memory is normally involved in this retention of recent speech. Retaining recent speech in working memory may fulfill a variety of functions for speaker and listener, among them the correct production and interpretation of surface anaphora. Reusing recent materials may, moreover, be more economical than regenerating speech anew from a semantic base, and thus contribute to fluency. But the realization of this strategy requires a production system in which linguistic formulation can take place relatively independent of, and parallel to, conceptual planning.

Abstract

The present paper studies how, in deictic expressions, the temporal interdependency of speech and gesture is realized in the course of motor planning and execution. Two theoretical positions were compared. On the “interactive” view the temporal parameters of speech and gesture are claimed to be the result of feedback between the two systems throughout the phases of motor planning and execution. The alternative “ballistic” view, however, predicts that the two systems are independent during the phase of motor execution, the temporal parameters having been preestablished in the planning phase. In four experiments subjects were requested to indicate which of an array of referent lights was momentarily illuminated. This was done by pointing to the light and/or by using a deictic expression (this/that light). The temporal and spatial course of the pointing movement was automatically registered by means of a Selspot opto-electronic system. By analyzing the moments of gesture initiation and apex, and relating them to the moments of speech onset, it was possible to show that, for deictic expressions, the ballistic view is very nearly correct.

Abstract

In his paper, MacKay reviews his Node Structure theory of error detection, but precedes it with a critical discussion of the Perceptual Loop theory of self-monitoring proposed in Levelt (1983, 1989). The present commentary is concerned with this latter critique and shows that there are more than casual problems with MacKay’s argumentation.

Abstract

PdR Press publications in cognition ; 1

Abstract

It is quite normal for us to produce one or two million word tokens every year. Speaking is a dear occupation and producing words is at the core of it. Still, producing even a single word is a highly complex affair. Recently, Levelt, Roelofs, and Meyer (1999) reviewed their theory of lexical access in speech production, which dissects the word-producing mechanism as a staged application of various dedicated operations. The present paper begins by presenting a bird eye's view of this mechanism. We then square the complexity by asking how speakers control multiple access in generating simple utterances such as a table and a chair. In particular, we address two issues. The first one concerns dependency: Do temporally contiguous access procedures interact in any way, or do they run in modular fashion? The second issue concerns temporal alignment: How much temporal overlap of processing does the system tolerate in accessing multiple content words, such as table and chair? Results from picture-word interference and eye tracking experiments provide evidence for restricted cases of dependency as well as for constraints on the temporal alignment of access procedures.

Abstract

This questionnaire is designed to explore how spatial relations are encoded in Australian language, but may be of interest to researchers further afield.

Abstract

This questionnaire is designed to explore how spatial relations are encoded in Australian language, but may be of interest to researchers further afield.

Abstract

It has been hypothesised that human reasoning has a non-linguistic foundation, but is nevertheless influenced by the formal means available in a language. For example, Western logic is transparently related to European sentential connectives (e.g., and, if … then, or, not), some of which cannot be unambiguously expressed in other languages. The questionnaire explores reasoning tools and practices through investigating translation equivalents of English sentential connectives and collecting examples of “reasoned arguments”.

Abstract

These classic tasks can be used to explore spatial reference in field settings. They provide a language-independent metric for eliciting spatial language, using a “director-matcher” paradigm. The Man and Tree task deals with location on the horizontal plane with both featured (man) and non-featured (e.g., tree) objects. The Space Games depict various objects (e.g. bananas, lemons) and elicit spatial contrasts not obviously lexicalisable in English.

Abstract

This article explores the relation between language and cognition by examining the case of "absolute" (cardinal direction) spatial description in the Australian aboriginal language Guugu Yimithirr. This kind of spatial description is incongruent with the "relative" (e.g., left/right/front/back) spatial description familiar in European languages. Building on Haviland's 1993 analysis of Guugu Yimithirr directionals in speech and gesture, a series of informal experiments were developed. It is shown that Guugu Yimithirr speakers predominantly code for nonverbal memory in "absolute" concepts congruent with their language, while a comparative sample of Dutch speakers do so in "relative" concepts. Much anecdotal evidence also supports this. The conclusion is that Whorfian effects may in fact be demonstrable in the spatial domain.

Abstract

Survey article

Abstract

The theory of basic color terms was a crucial factor in the demise of linguistic relativity. The theory is now once again under scrutiny and fundamental revision. This article details a case study that undermines one of the central claims of the classical theory, namely that languages universally treat color as a unitary domain, to be exhaustively named. Taken together with other cases, the study suggests that a number of languages have only an incipient color terminology, raising doubts about the linguistic universality of such terminology.

Abstract

We propose that the choice between the auxiliaries hebben 'have' and zijn 'be' in Dutch is determined by a particular semantic feature of verbs. In particular we propose a feature of meaning [IEPS] for 'inferable eventual position or state' that characterizes whether the action denoted by the verb allows us to determine the eventual position or state of the verb's highest argument. It is argued that only verbs which exhibit the feature [+IEPS] or which obtain the feature compositionally in the syntax select zijn as their auxiliary. Our analysis is then compared to a number of other analyses of auxiliary selection in Dutch.

Abstract

Mutations of the renal-specific chloride channel (CLCN5) gene, which is located on chromosome Xp11.22, are associated with hypercalciuric nephrolithiasis (kidney stones) in the Northern European and Japanese populations. CLCN5 encodes a 746 amino acid channel (CLC-5) that has approximately 12 transmembrane domains, and heterologous expression of wild-type CLC-5 in Xenopus oocytes has yielded outwardly rectifying chloride currents that were markedly reduced or abolished by these mutations. In order to assess further the structural and functional relationships of this recently cloned chloride channel, additional CLCN5 mutations have been identified in five unrelated families with this disorder. Three of these mutations were missense (G57V, G512R and E527D), one was a nonsense (R648Stop) and one was an insertion (30:H insertion). In addition, two of the mutations (30:H insertion and E527D) were demonstrated to be de novo, and the G57V and E527D mutations were identified in families of Afro-American and Indian origin, respectively. The G57V and 30:H insertion mutations represent the first CLCN5 mutations to be identified in the N-terminus region, and the R648Stop mutation, which has been observed previously in an unrelated family, suggests that this codon may be particularly prone to mutations. Heterologous expression of the mutations resulted in a marked reduction or abolition of the chloride currents, thereby establishing their functional importance. These results help to elucidate further the structure-function relationships of this renal chloride channel.

Abstract

Several models of spoken word recognition postulate that recognition is achieved via a process of competition between lexical hypotheses. Competition not only provides a mechanism for isolated word recognition, it also assists in continuous speech recognition, since it offers a means of segmenting continuous input into individual words. We present statistics on the pattern of occurrence of words embedded in the polysyllabic words of the English vocabulary, showing that an overwhelming majority (84%) of polysyllables have shorter words embedded within them. Positional analyses show that these embeddings are most common at the onsets of the longer word. Although both phonological and syntactic constraints could rule out some embedded words, they do not remove the problem. Lexical competition provides a means of dealing with lexical embedding. It is also supported by a growing body of experimental evidence. We present results which indicate that competition operates both between word candidates that begin at the same point in the input and candidates that begin at different points (McQueen, Norris, & Cutler, 1994, Noms, McQueen, & Cutler, in press). We conclude that lexical competition is an essential component in models of continuous speech recognition.

Abstract

Lexical knowledge influences how human listeners make decisions about speech sounds. Positive lexical effects (faster responses to target sounds in words than in nonwords) are robust across several laboratory tasks, while negative effects (slower responses to targets in more word-like nonwords than in less word-like nonwords) have been found in phonetic decision tasks but not phoneme monitoring tasks. The present experiments tested whether negative lexical effects are therefore a task-specific consequence of the forced choice required in phonetic decision. We compared phoneme monitoring and phonetic decision performance using the same Dutch materials in each task. In both experiments there were positive lexical effects, but no negative lexical effects. We observe that in all studies showing negative lexical effects, the materials were made by cross-splicing, which meant that they contained perceptual evidence supporting the lexically-consistent phonemes. Lexical knowledge seems to influence phonemic decision-making only when there is evidence for the lexically-consistent phoneme in the speech signal.

Abstract

We briefly describe the Merge model of phonemic decision-making, and, in the light of general arguments about the possible role of feedback in spoken-word recognition, defend Merge's feedforward structure. Merge not only accounts adequately for the data, without invoking feedback connections, but does so in a parsimonious manner.

Abstract

This paper presents lexical statistics on the pattern of occurrence of words embedded in other words. We report the results of an analysis of 25000 words, varying in length from two to six syllables, extracted from a phonetically-coded English dictionary (The Longman Dictionary of Contemporary English). Each syllable, and each string of syllables within each word was checked against the dictionary. Two analyses are presented: the first used a complete list of polysyllables, with look-up on the entire dictionary; the second used a sublist of content words, counting only embedded words which were themselves content words. The results have important implications for models of human speech recognition. The efficiency of these models depends, in different ways, on the number and location of words within words.

Abstract

A comparison of Merge, a model of comprehension, and WEAVER, a model of production, raises five issues: (1) merging models of comprehension and production necessarily creates feedback; (2) neither model is a comprehensive account of word processing; (3) the models are incomplete in different ways; (4) the models differ in their handling of competition; (5) as opposed to WEAVER, Merge is a model of metalinguistic behavior.

Abstract

Phonological encoding in language production can be defined as a set of processes generating utterance forms on the basis of semantic and syntactic information. Most evidence about these processes stems from analyses of sound errors. In section 1 of this paper, certain important results of these analyses are reviewed. Two prominent models of phonological encoding, which are mainly based on speech error evidence, are discussed in section 2. In section 3, limitations of speech error analyses are discussed, and it is argued that detailed and comprehensive models of phonological encoding cannot be derived solely on the basis of error analyses. As is argued in section 4, a new research strategy is required. Instead of using the properties of errors to draw inferences about the generation of correct word forms, future research should directly investigate the normal process of phonological encoding.

Abstract

Tip-of-the-tongue states may represent the momentary unavailability of an otherwise accessible word or the weak activation of an otherwise inaccessible word. In three experiments designed to address these alternative views, subjects attempted to retrieve rare target words from their definitions. The definitions were followed by cues that were related to the targets in sound, by cues that were related in meaning, and by cues that were not related to the targets. Experiment 1 found that compared with unrelated cues, related cue words that were presented immediately after target definitions helped rather than hindered lexical retrieval, and that sound cues were more effective retrieval aids than meaning cues. Experiment 2 replicated these results when cues were presented after an initial target-retrieval attempt. These findings reverse a previous one (Jones, 1989) that was reproduced in Experiment 3 and shown to stem from a small group of unusually difficult target definitions.

Abstract

Spoken utterances contain few reliable cues to word boundaries, but listeners nonetheless experience little difficulty identifying words in continuous speech. The authors present data and simulations that suggest that this ability is best accounted for by a model of spoken-word recognition combining competition between alternative lexical candidates and sensitivity to prosodic structure. In a word-spotting experiment, stress pattern effects emerged most clearly when there were many competing lexical candidates for part of the input. Thus, competition between simultaneously active word candidates can modulate the size of prosodic effects, which suggests that spoken-word recognition must be sensitive both to prosodic structure and to the effects of competition. A version of the Shortlist model ( D. G. Norris, 1994b) incorporating the Metrical Segmentation Strategy ( A. Cutler & D. Norris, 1988) accurately simulates the results using a lexicon of more than 25,000 words.

Abstract

The central thesis of the target article was that feedback is never necessary in spoken word recognition. The commentaries present no new data and no new theoretical arguments which lead us to revise this position. In this response we begin by clarifying some terminological issues which have lead to a number of significant misunderstandings. We provide some new arguments to support our case that the feedforward model Merge is indeed more parsimonious than the interactive alternatives, and that it provides a more convincing account of the data than alternative models. Finally, we extend the arguments to deal with new issues raised by the commentators such as infant speech perception and neural architecture.

Abstract

Top-down feedback does not benefit speech recognition; on the contrary, it can hinder it. No experimental data imply that feedback loops are required for speech recognition. Feedback is accordingly unnecessary and spoken word recognition is modular. To defend this thesis, we analyse lexical involvement in phonemic decision making. TRACE (McClelland & Elman 1986), a model with feedback from the lexicon to prelexical processes, is unable to account for all the available data on phonemic decision making. The modular Race model (Cutler & Norris 1979) is likewise challenged by some recent results, however. We therefore present a new modular model of phonemic decision making, the Merge model. In Merge, information flows from prelexical processes to the lexicon without feedback. Because phonemic decisions are based on the merging of prelexical and lexical information, Merge correctly predicts lexical involvement in phonemic decisions in both words and nonwords. Computer simulations show how Merge is able to account for the data through a process of competition between lexical hypotheses. We discuss the issue of feedback in other areas of language processing and conclude that modular models are particularly well suited to the problems and constraints of speech recognition.

Abstract

Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) [1] is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and a known boundary. The experiments examined cases where the residue was either a CV syllable with a lax vowel, or a CVC syllable with a schwa. Although neither syllable context is a possible word in English, word-spotting in both contexts was easier than with a context consisting of a single consonant. The PWC appears to be language-universal rather than language-specific.

Abstract

We report two experiments in which vowels and steady-state consonants served as targets in a speeded detection task. In the first experiment, two vowels were compared with one voiced and once unvoiced fricative. Response times (RTs) to the vowels were longer than to the fricatives. The error rate was higher for the consonants. Consonants in word-final position produced the shortest RTs, For the vowels, RT correlated negatively with target duration. In the second experiment, the same two vowel targets were compared with two nasals. This time there was no significant difference in RTs, but the error rate was still significantly higher for the consonants. Error rate and length correlated negatively for the vowels only. We conclude that RT differences between phonemes are independent of vocalic or consonantal status. Instead, we argue that the process of phoneme detection reflects more finely grained differences in acoustic/articulatory structure within the phonemic repertoire.

Abstract

Simulations explored the inability of the TRACE model of spoken-word recognition to model the effects on human listening of subcategorical mismatch in word forms. The source of TRACE's failure lay not in interactive connectivity, not in the presence of inter-word competition, and not in the use of phonemic representations, but in the need for continuously optimised interpretation of the input. When an analogue of TRACE was allowed to cycle to asymptote on every slice of input, an acceptable simulation of the subcategorical mismatch data was achieved. Even then, however, the simulation was not as close as that produced by the Merge model, which has inter-word competition, phonemic representations and continuous optimisation (but no interactive connectivity).

Abstract

We propose that word recognition in continuous speech is subject to constraints on what may constitute a viable word of the language. This Possible-Word Constraint (PWC) reduces activation of candidate words if their recognition would imply word status for adjacent input which could not be a word - for instance, a single consonant. In two word-spotting experiments, listeners found it much harder to detectapple,for example, infapple(where [f] alone would be an impossible word), than invuffapple(wherevuffcould be a word of English). We demonstrate that the PWC can readily be implemented in a competition-based model of continuous speech recognition, as a constraint on the process of competition between candidate words; where a stretch of speech between a candidate word and a (known or likely) word boundary is not a possible word, activation of the candidate word is reduced. This implementation accurately simulates both the present results and data from a range of earlier studies of speech segmentation.

Abstract

A database is presented of relative familiarity ratings for 24 sets of Japanese words, each set comprising words overlapping in the initial portions. These ratings are useful for the generation of material sets for research in the recognition of spoken words.

Abstract

Japanese, British English and American English listeners were presented with spoken words in their native language, and asked to mark on a written transcript of each word the first natural division point in the word. The results showed clear and strong patterns of consensus, indicating that listeners have available to them conscious representations of within-word structure. Orthography did not play a strongly deciding role in the results. The patterns of response were at variance with results from on-line studies of speech segmentation, suggesting that the present task taps not those representations used in on-line listening, but levels of representation which may involve much richer knowledge of word-internal structure.

Abstract

Evaluation plays a role in the telling and understanding of narratives, in communicative interaction, emotional understanding, and in psychological well-being. This article reports a study of evaluation by describing how readers monitor the concerns of characters over the course of a narrative. The main hypothesis is that readers tract the well-being via the expression of a character's internal states. Reader evaluations were revealed in think aloud protocols obtained during reading of narrative texts, one sentence at a time. Five kinds of evaluative inferences were found: appraisals (good versus bad), preferences (like versus don't like), emotions (happy versus frustrated), goals (want versus don't want), or purposes (to attain or maintain X versus to prevent or avoid X). Readers evaluated all sentences. The mean rate of evaluation per sentence was 0.55. Positive and negative evaluations over the course of the story indicated that things initially went badly for characters, improved with the formulation and execution of goal plans, declined with goal failure, and improved as characters formulated new goals and succeeded. The kind of evaluation made depended upon the episodic category of the event and the event's temporal location in the story. Evaluations also served to explain or predict events. In making evaluations, readers stayed within the frame of the story and perspectives of the character or narrator. They also moved out of the narrative frame and addressed evaluations towards the experimenter in a communicative context.

Abstract

Dutch and Spanish differ in how predictable the stress pattern is as a function of the segmental content: it is correlated with syllable weight in Dutch but not in Spanish. In the present study, two experiments were run to compare the abilities of Dutch and Spanish speakers to separately process segmental and stress information. It was predicted that the Spanish speakers would have more difficulty focusing on the segments and ignoring the stress pattern than the Dutch speakers. The task was a speeded classification task on CVCV syllables, with blocks of trials in which the stress pattern could vary versus blocks in which it was fixed. First, we found interference due to stress variability in both languages, suggesting that the processing of segmental information cannot be performed independently of stress. Second, the effect was larger for Spanish than for Dutch, suggesting that that the degree of interference from stress variation may be partially mitigated by the predictability of stress placement in the language.

Abstract

"Event realisation" refers to the normal final state of the affected entity of an activity described by a verb. For example, the sentence John killed the mosquito entails that the mosquito is afterwards dead – this is the full realisation of a killing event. By contrast, a sentence such as John hit the mosquito does not entail the mosquito’s death (even though we might assume this to be a likely result). In using a certain verb, which features of event realisation are entailed and which are just likely? This questionnaire supports cross-linguistic exploration of event realisation for a range of event types.

Abstract

In this paper we follow two beginning learners of English, Andrea and Santo, over a period of 2 years as they develop means to structure the declarative utterances they produce in various production tasks, and then we look at the following problem: In the early stages of acquisition, both learners develop a common learner variety; during these stages, we see a picture of two learner varieties developing similar regularities determined by the minimal requirements of the tasks we examine. Andrea subsequently develops further morphosyntactic means to achieve greater cohesion in his discourse. But Santo does not. Although we can identify contexts where the grammaticalization of Andrea's production allows him to go beyond the initial constraints of his variety, it is much more difficult to ascertain why Santo, faced with the same constraints in the same contexts, does not follow this path. Some lines of investigation into this problem are then suggested.

Abstract

Understanding the role of the medial temporal lobe (MTL) in learning and memory is an important problem in cognitive neuroscience. Memory and learning processes that depend on the function of the MTL and related diencephalic structures (e.g., the anterior and mediodorsal thalamic nuclei) are defined as declarative. We have studied the MTL activity as indicated by regional cerebral blood flow with positron emission tomography and statistical parametric mapping during recall of abstract designs in a less practiced memory state as well as in a well-practiced (well-encoded) memory state. The results showed an increased activity of the MTL bilaterally (including parahippocampal gyrus extending into hippocampus proper, as well as anterior lingual and anterior fusiform gyri) during retrieval in the less practiced memory state compared to the well-practiced memory state, indicating a dynamic role of the MTL in retrieval during the learning processes. The results also showed that the activation of the MTL decreases as the subjects learn to draw abstract designs from memory, indicating a changing role of the MTL during recall in the earlier stages of acquisition compared to the well-encoded declarative memory state.

Abstract

It has previously been suggested that the activity in sensory regions of the brain can be modulated by attentional mechanisms during parallel cognitive processing. To investigate whether such attention-related modulations are present in the processing of pain, the regional cerebral blood ¯ow was measured using [15O]butanol and positron emission tomography in conditions involving both pain and parallel cognitive demands. The painful stimulus consisted of the standard cold pressor test and the cognitive task was a computerised perceptual maze test. The activations during the maze test reproduced findings in previous studies of the same cognitive task. The cold pressor test evoked signi®cant activity in the contralateral S1, and bilaterally in the somatosensory association areas (including S2), the ACC and the mid-insula. The activity in the somatosensory association areas and periaqueductal gray/midbrain were significantly modified, i.e. relatively decreased, when the subjects also were performing the maze task. The altered activity was accompanied with significantly lower ratings of pain during the cognitive task. In contrast, lateral orbitofrontal regions showed a relative increase of activity during pain combined with the maze task as compared to only pain, which suggests the possibility of the involvement of frontal cortex in modulation of regions processing pain

Abstract

In this study we test a number of different claims about the nature of stylistic variation at the “single-word” stage by examining the relation between variation in early vocabulary composition, variation in early language use, and variation in the structural and functional propreties of mothers' child-directed speech. Maternal-report and observational data were collected for 26 children at 10, 50, and 100 words, These were then correlated with a variety of different measures of maternal speech at 10 words, The results show substantial variation in the percentage of common nouns and unanalyzed phrases in children's vocabularies, and singficant relations between this variation and the way in which language is used by the child. They also reveal singficant relations between the way in whch mothers use language at 10 words and the way in chich their children use language at 50 words and between certain formal properties of mothers speech at 10 words and the percentage of common nouns and unanalyzed phrases in children's early vocabularies, However, most of these relations desappear when an attempt is made to control for ossible effects of the child on the mother at Time 1. The exception is a singficant negative correlation between mothers tendency to produce speech that illustrates word boundaries and the percentage of unanalyzed phrases at 50 and 100 words. This suggests that mothers whose sprech provides the child with information about where new words begin and end tend to have children with few unanalyzed. phrases in their early vocabularies.

Abstract

In this paper hypothesis‐testing behaviour is compared to risk‐taking behaviour. It is proposed that choosing a suitable test for a given hypothesis requires making a preposterior analysis of two aspects of such a test: the probability of obtaining supporting evidence and the evidential value of this evidence. This consideration resembles the one a gambler makes when choosing among bets, each having a probability of winning and an amount to be won. A confirmatory testing strategy can be defined within this framework as a strategy directed at maximizing either the probability or the value of a confirming outcome. Previous theories on testing behaviour have focused on the human tendency to maximize the probability of a confirming outcome. In this paper, two experiments are presented in which participants tend to maximize the confirming value of the test outcome. Motivational factors enhance this tendency dependent on the context of the testing situation. Both this result and the framework are discussed in relation to other studies in the field of testing behaviour.

Abstract

Lexical access in speaking consists of two major steps: lemma retrieval and word-form encoding. In Roelofs (Roelofs, A. 1992a. Cognition 42. 107-142; Roelofs. A. 1993. Cognition 47, 59-87.), I described a model of lemma retrieval. The present paper extends this work by presenting a comprehensive model of the second access step, word-form encoding. The model is called WEAVER (Word-form Encoding by Activation and VERification). Unlike other models of word-form generation, WEAVER is able to provide accounts of response time data, particularly from the picture-word interference paradigm and the implicit priming paradigm. Its key features are (1) retrieval by spreading activation, (2) verification of activated information by a production rule, (3) a rightward incremental construction of phonological representations using a principle of active syllabification, syllables are constructed on the fly rather than stored with lexical items, (4) active competitive selection of syllabic motor programs using a mathematical formalism that generates response times and (5) the association of phonological speech errors with the selection of syllabic motor programs due to the failure of verification.

Abstract

The present paper reports an analysis of correct wh-question production and subject–auxiliary inversion errors in one child's early wh-question data (age 2; 3.4 to 4; 10.23). It is argued that two current movement rule accounts (DeVilliers, 1991; Valian, Lasser & Mandelbaum, 1992) cannot explain the patterning of early wh-questions. However, the data can be explained in terms of the child's knowledge of particular lexically-specific wh-word+auxiliary combinations, and the pattern of inversion and uninversion predicted from the relative frequencies of these combinations in the mother's speech. The results support the claim that correctly inverted wh-questions can be produced without access to a subject–auxiliary inversion rule and are consistent with the constructivist claim that a distributional learning mechanism that learns and reproduces lexically-specific formulae heard in the input can explain much of the early multi-word speech data. The implications of these results for movement rule-based and constructivist theories of grammatical development are discussed.

Abstract

Recent studies of wh-question acquisition have tended to come from the nativist side of the language acquisition debate with little input from a constructivist perspective. The present work was designed to redress the balance, first by presenting a detailed description of young children's wh-question acquisition data, second, by providing detailed critiques of two nativist theories of wh- question acquisition, and third, by presenting a preliminary account of young children's wh-question development from a constructivist perspective. Analyses of the data from twelve 2 to 3 year old children collected over a year and of data from an older child (Adam from the Brown corpus, 1973) are described and three conclusions are drawn. First it is argued that the data suggest that children's knowledge of how to form wh-questions builds up gradually as they learn how to combine lexical items such as wh-words and auxiliaries in specific ways. Second, it is concluded that two nativist theories of grammatical development (Radford, 1990, 1992, 1995, 1996, Valian, Lasser & Mandelbaum, 1992) fail to account successfully for the wh-question data produced by the children. Third, it is asserted that the lexically-specific nature of children's early wh-questions is compatible with a lexical constructivist view of development, which proposes that the language learning mechanism learns by picking up high frequency lexical patterns from the input. The implications of these conclusions for theories of language development and future research are discussed.

Abstract

Capacity limited memory systems need to gradually forget old information in order to avoid catastrophic forgetting where all stored information is lost. This can be achieved by allowing new information to overwrite old, as in the so-called palimpsest memory. This paper describes a new such learning rule employed in an attractor neural network. The network does not exhibit catastrophic forgetting, has a capacity dependent on the learning time constant and exhibits recency e!ects in retrieval