Publications

Abstract

Presentation of the official opening of the Jerome Bruner Library, January 8th, 2020

Abstract

Reproduced with permission of Blackwell Publishing from: Levinson, S. C. (2004) 'Deixis'. In: Horn, L.R. and Ward, G. (Eds.) The Handbook of Pragmatics. Oxford: Blackwell Publishing, pp. 100-121

Abstract

Demonstratives are key items in understanding how a language constructs and interprets spatial relationships. They are also multi-functional, with applications to non-spatial deictic fields such as time, perception, person and discourse, and uses in anaphora and affect marking. This item consists of an overview of theoretical distinctions in demonstrative systems, followed by a set of practical queries and elicitation suggestions for demonstratives in “table top” space, wider spatial fields, and naturalistic data.

Abstract

The world’s languages encode a diverse range of topological relations. However, cross-linguistic investigation suggests that the relations IN, AT and ON are especially fundamental to the grammaticised expression of space. The purpose of this questionnaire is to collect information about adpositions, case markers, and spatial nominals that are involved in the expression of core IN/AT/ON meanings. The task explores the more general parts of a language’s topological system, with a view to testing certain hypotheses about the packaging of spatial concepts. The questionnaire consists of target translation sentences that focus on a number of dimensions including animacy, caused location and motion.

Abstract

Languages differ widely in terms of how they encode the fundamental concepts of location and position. For some languages, verbs have an important role to play in describing situations (e.g., whether a bottle is standing or lying on the table); for others, verbs are not used in describing location at all. This item outlines certain hypotheses concerning four “types” of languages: those that have verbless basic locatives; those that use a single verb; those that have several verbs available to express location; and those that use positional verbs. The document was originally published as an appendix to the 'Picture series for positional verbs' (https://doi.org/10.17617/2.2573831).

Abstract

Reprinted with permission of The MIT Press from Levinson (2000) Presumptive meanings: The theory of generalized conversational implicature, pp. 112-118, 116-167, 170-173, 177-180. MIT Press

Abstract

This paper describes the linguistic treatment of placement events in the Rossel Island (Papua New Guinea) language Yélî Dnye. Yélî Dnye is unusual in treating PUT and TAKE events symmetrically with a remarkable consistency. In what follows, we first provide a brief background for the language, then describe the six core PUT/TAKE verbs that were drawn upon by Yélî Dnye speakers to describe the great majority of the PUT/TAKE stimuli clips, along with some of their grammatical properties. In Section 5 we describe alternative verbs usable in particular circumstances and give an indication of the basis for variability in responses across speakers. Section 6 presents some reasons why the Yélî verb pattern for expressing PUT and TAKE events is of broad interest.

Abstract

Yélî Dnye has two discernable dedicated constructions for reciprocal marking. The first and main construction uses a dedicated reciprocal pronoun numo, somewhat like English each other. We can recognise two subconstructions. First, the ‘numo-construction’, where the reciprocal pronoun is a patient of the verb, and where the invariant pronoun numo is obligatorily incorporated, triggering intransitivisation (e.g. A-NPs become absolutive). This subconstruction has complexities, for example in the punctual aspect only, the verb is inflected like a transitive, but with enclitics mismatching actual person/number. In the second variant or subconstruction, the ‘noko-construction’, the same reciprocal pronoun (sometimes case-marked as noko) occurs but now in oblique positions with either transitive or intransitive verbs. The reciprocal element here has some peculiar binding properties. Finally, the second independent construction is a dedicated periphrastic (or woni…woni) construction, glossing ‘the one did X to the other, and the other did X to the one’. It is one of the rare cross-serial dependencies that show that natural languages cannot be modelled by context-free phrase-structure grammars. Finally, the usage of these two distinct constructions is discussed.

Abstract

The essential insight of speech act theory was that when we use language, we perform actions—in a more modern parlance, core language use in interaction is a form of joint action. Over the last thirty years, speech acts have been relatively neglected in linguistic pragmatics, although important work has been done especially in conversation analysis. Here we review the core issues—the identifying characteristics, the degree of universality, the problem of multiple functions, and the puzzle of speech act recognition. Special attention is drawn to the role of conversation structure, probabilistic linguistic cues, and plan or sequence inference in speech act recognition, and to the centrality of deep recursive structures in sequences of speech acts in conversation

Abstract

Reprint from Stephen C. Levinson, ‘Three Levels of Meaning’, in Frank Palmer (ed.), Grammar and Meaning: Essays in Honor of Sir John Lyons (Cambridge University Press, 1995), pp. 90–115

Abstract

This entry contains: 1. An invitation to think about to what extent the grammar of space and time share lexical and morphosyntactic resources − the suggestions here are only prompts, since it would take a long questionnaire to fully explore this; 2. A suggestion about how to collect gestural data that might show us to what extent the spatial and temporal domains, have a psychological continuity. This is really the goal − but you need to do the linguistic work first or in addition. The goal of this task is to explore the extent to which time is conceptualised on a spatial basis.

Abstract

Changing Prospects for Universals in Pragmatics
The term PRAGMATICS has come to denote the study of general principles of language use. It is usually understood to contrast with SEMANTICS, the study of encoded meaning, and also, by some authors, to contrast with SOCIOLINGUISTICS
and the ethnography of speaking, which are more concerned with local sociocultural practices. Given that pragmaticists come from disciplines as varied as philosophy, sociology,
linguistics, communication studies, psychology, and anthropology, it is not surprising that definitions of pragmatics vary. Nevertheless, most authors agree on a list of topics
that come under the rubric, including DEIXIS, PRESUPPOSITION,
implicature (see CONVERSATIONAL IMPLICATURE), SPEECH-ACTS, and conversational organization (see CONVERSATIONAL ANALYSIS). Here, we can use this extensional definition as a starting point (Levinson 1988; Huang 2007).

Abstract

Recent research suggests that 12-month-old infants in German cultural settings have the motive of sharing their attention to and interest in various events with a social interlocutor. To do so, these preverbal infants predominantly use the pointing gesture (in this case the extended arm with or without extended index finger) as a means to direct another person’s attention. This task systematically investigates different types of motives underlying infants’ pointing. The occurrence of a protodeclarative (as opposed to protoimperative) motive is of particular interest because it requires an understanding of the recipient’s psychological states, such as attention and interest, that can be directed and accessed.

Abstract

This Field Manual entry has been superceded by the 2009 version:
https://doi.org/10.17617/2.883570

Abstract

In this task we aim to find what the best exemplars or “focal colours” of each basic colour term is in our field languages. This is an important part of the evidence we need in order to understand the colour data collected using 'The Language of Vision I: Colour'. This task consists of an experiment where participants pick out the best exemplar for the colour terms in their language. The goal is to establish language specific focal colours.

Abstract

There are three main strands of research which have investigated people’s intuitive knowledge of objects in motion. (1) Knowledge of the trajectories of objects in motion; (2) knowledge of the causes of motion; and (3) the categorisation of motion as to whether it has been produced by something animate or inanimate. We provide a brief introduction to each of these areas. We then point to some linguistic and cultural differences which may have consequences for people’s knowledge of objects in motion. Finally, we describe two experimental tasks and an ethnographic task that will allow us to collect data in order to establish whether, indeed, there are interesting cross-linguistic/cross-cultural differences in lay theories of objects in motion.

Abstract

The project that we describe in this chapter has the theme ‘Language of the senses’. This theme is
based on the research of Asifa Majid and her team regarding the influence of language and culture on
sensory perception. The chapter consists of two sections. Section 2.1 describes how different sensory
perceptions are spoken of in different languages. Teachers can use this section as substantive preparation
before they launch this theme in the classroom. Section 2.2 describes how teachers can handle
this theme in accordance with the seven phases of inquiry-based learning. Chapter 1, in which the
general guideline of the seven phases is described, forms the basis for this. We therefore recommend
the use of chapter 1 as the starting point for the execution of a project in the classroom. This chapter
provides the thematic additions.

Abstract

Taal der zintuigen gaat over de invloed van taal en cultuur op zintuiglijke waarnemingen. Hoe omschrijf je wat je ziet, voelt, proeft of ruikt? In sommige culturen zijn er veel verschillende woorden voor kleur, in andere culturen juist weer heel weinig. Worden we geboren met deze verschillende kleurgroepen? En bepaalt hoe je ergens over praat ook wat je waarneemt?

Abstract

How similar are reciprocal constructions in the semantic parameters they encode? We investigate this question by using an extensional approach, which examines similarity of meaning by examining how constructions are applied over a set of 64 videoclips depicting reciprocal events (Evans et al. 2004). We apply statistical modelling to descriptions from speakers of 20 languages elicited using the videoclips. We show that there are substantial differences in meaning between constructions of different languages.

Abstract

La ciencia moderna nace de la conjunción entre postulados teóricos y el desarrollo de una infraestructura tecnológica que permite observar los hechos de manera adecuada, realizar experimentos y verificar las hipótesis. Desde Galileo, ciencia y tecnología han avanzado conjuntamente. En el mundo occidental, la ciencia ha evolucionado desde pro-puestas puramente especulativas (basadas en postulados apriorísticos) hasta el uso de métodos experimentales y estadísticos para explicar mejor nuestras observaciones. La tecnología se hermana con la ciencia facilitando al investigador una aproximación adecuada a los hechos que pretende explicar. Así, Galileo, para observar los cuerpos celestes, mejoró el utillaje óptico, lo que le permitió un acercamiento más preciso al objeto de estudio y, en consecuencia, unos fundamentos más sólidos para su propuesta teórica. De modo similar, actualmente el desarrollo tecnológico digital ha posibilitado la extracción masiva de datos y el análisis estadístico de éstos para verificar las hipótesis de partida: la lingüística no ha podido dar el paso desde la pura especulación hacia el análisis estadístico de los hechos hasta la aparición de las tecnologías digitales.

Abstract

This chapter outlines a Bayesian model of spoken-word recognition and reviews how
prosody is part of that model. The review focuses on the information that assists the lis­
tener in recognizing the prosodic structure of an utterance and on how spoken-word
recognition is also constrained by prior knowledge about prosodic structure. Recognition
is argued to be a process of perceptual inference that ensures that listening is robust to
variability in the speech signal. In essence, the listener makes inferences about the seg­
mental content of each utterance, about its prosodic structure (simultaneously at differ­
ent levels in the prosodic hierarchy), and about the words it contains, and uses these in­
ferences to form an utterance interpretation. Four characteristics of the proposed
prosody-enriched recognition model are discussed: parallel uptake of different informa­
tion types, high contextual dependency, adaptive processing, and phonological abstrac­
tion. The next steps that should be taken to develop the model are also discussed.

Abstract

The goal of speech perception is understanding a speaker's message. To achieve this, listeners must recognize the words that comprise a spoken utterance. This in turn implies distinguishing these words from other minimally different words (e.g., word from bird, etc.), and this involves making phonemic distinctions. The article summarizes research on the perception of phonemic distinctions, on how listeners cope with the continuity and variability of speech signals, and on how phonemic information is mapped onto the representations of words. Particular attention is paid to theories of speech perception and word recognition.

Abstract

Many languages have general or “light” verbs used by speakers to describe a wide range of situations owing to their relatively schematic meanings, e.g., the English verb do that can be used to describe many different kinds of actions, or the verb put that labels a range of types of placement of objects at locations. Such semantically bleached verbs often become grammaticalized and used to encode an extended (set of) meaning(s), e.g., Tamil veyyii ‘put/place’ is used to encode causative meaning in periphrastic causatives (e.g., okkara veyyii ‘make sit’, nikka veyyii ‘make stand’). But do general verbs in different languages have the same kinds of (schematic) meanings and extensional ranges? Or do they reveal different, perhaps even cross-cutting, ways of structuring the same semantic domain in different languages? These questions require detailed crosslinguistic investigation using comparable methods of eliciting data. The present study is a first step in this direction, and focuses on the use of general verbs to describe events of placement and removal in two South Asian languages, Hindi and Tamil.

Abstract

The human language processor is conceived as a system that consists of several interrelated subsystems. Each subsystem performs a specific task in the complex process of language comprehension and production. A subsystem receives a particular input, performs certain specific operations on this input and yields a particular output. The subsystems can be characterized in terms of the transformations that relate the input representations to the output representations. An important issue in describing the language processing system is to identify the subsystems and to specify the relations between the subsystems. These relations can be conceived in two different ways. In one conception the subsystems are autonomous. They are related to each other only by the input-output channels. The operations in one subsystem are not affected by another system. The subsystems are modular, that is they are independent. In the other conception, the different subsystems influence each other. A subsystem affects the processes in another subsystem. In this conception there is an interaction between the subsystems.

Abstract

This article explores the expression of placement and removal events in Moroccan Arabic, particularly the semantic features of ‘putting’ and ‘taking’ verbs, classified in accordance with their combination with Goal and/or Source NPs. Moroccan Arabic verbs encode a variety of components of placement and removal events, including containment, attachment, features of the figure, and trajectory. Furthermore, accidental events are distinguished from deliberate events either by the inherent semantics of predicates or denoted syntactically. The postures of the Figures, in spite of some predicates distinguishing them, are typically not specified as they are in other languages, such as Dutch. Although Ground locations are frequently mentioned in both source-oriented and goal-oriented clauses, they are used more often in goal-oriented clauses.

Abstract

This paper offers a structural and semantic analysis of expressions of caused motion in Lowland Chontal of Oaxaca, an indigenous language of southern Mexico. The data were collected using a video stimulus designed to elicit a wide range of caused motion event descriptions. The most frequent event types in the corpus depict caused motion to and from relations of support and containment, fundamental notions in the de­scription of spatial relations between two entities and critical semantic components of the linguistic encoding of caused motion in this language. Formal features of verbal construction type and argument realization are examined by sorting event descriptions into semantic types of placement and removal, to and from support and to and from containment. Together with typological factors that shape the distribution of spatial semantics and referent expression, separate treatments of support and containment relations serve to clarify notable asymmetries in patterns of predicate type and argument realization.

Abstract

Most research focuses function of gesture independent of its link to the speech it accompanies and the coexpressive functions it has together with speech. This chapter instead approaches gesture in relation to its communicative function in relation to speech, and demonstrates how it is shaped by the linguistic encoding of a speaker’s message. Drawing on crosslinguistic research with adults and children as well as bilinguals on iconic/pointing gesture production it shows that the specific language speakers use modulates the rate and the shape of the iconic gesture production of the same events. The findings challenge the claims aiming to understand gesture’s function for “thinking only” in adults and during development.

Abstract

Gestures are meaningful movements of the body, the hands, and the face during communication,
which accompany the production of both spoken and signed utterances. Recent
research has shown that gestures are an integral part of language and that they contribute
semantic, syntactic, and pragmatic information to the linguistic utterance. Furthermore,
they reveal internal representations of the language user during communication in ways
that might not be encoded in the verbal part of the utterance. Firstly, this chapter summarizes
research on the role of gesture in spoken languages. Subsequently, it gives an overview
of how gestural components might manifest themselves in sign languages, that is,
in a situation in which both gesture and sign are expressed by the same articulators.
Current studies are discussed that address the question of whether gestural components are the same or different in the two language modalities from a semiotic as well as from a cognitive and processing viewpoint. Understanding the role of gesture in both sign and
spoken language contributes to our knowledge of the human language faculty as a multimodal communication system.

Abstract

Wanneer iemand goed is in het spreken van meerdere talen, wordt wel gezegd dat zo iemand een talenknobbel heeft. Iedereen weet dat dat niet letterlijk bedoeld is: iemand met een talenknobbel herkennen we niet aan een grote bult op zijn hoofd. Toch dacht men vroeger wel degelijk dat mensen een letterlijke talenknobbel konden ontwikkelen. Een goed ontwikkeld taalvermogen zou gepaard gaan met het groeien van het hersengebied dat hiervoor verantwoordelijk was. Dit deel van het brein zou zelfs zo groot kunnen worden dat het van binnenuit tegen de schedel drukte, met name rond de ogen. Nu weten we wel beter. Maar waar in het brein bevindt de taal zich dan wel precies?

Abstract

This chapter focuses on the semantic and pragmatic uses of space. The questions addressed concern how sign space (i.e. the area of space in front of the signer’s body) is used for meaning construction, how locations in sign space are associated with discourse referents, and how signers choose to structure sign space for their communicative intents. The chapter gives an overview of linguistic analyses of the use of space, starting with the distinction between syntactic and topographic uses of space and the different types of signs that function to establish referent-location associations, and moving to analyses based on mental spaces and conceptual blending theories. Semantic-pragmatic conventions for organizing sign space are discussed, as well as spatial devices notable in the visual-spatial modality (particularly, classifier predicates and signing perspective), which influence and determine the way meaning is created in sign space. Finally, the special role of simultaneity in sign languages is discussed, focusing on the semantic and discourse-pragmatic functions of simultaneous constructions.

Abstract

In Kalasha, an Indo-Aryan language spoken in Northwest Pakistan, the linguistic encoding of ‘put’ and ‘take’ events reveals a symmetry between lexical ‘put’ and ‘take’ verbs that implies ‘placement on’ and ‘removal from’ a supporting surface. As regards ‘placement in’ and ‘removal from’ an enclosure, the data reveal a lexical asymmetry as ‘take’ verbs display a larger degree of linguistic elaboration of the Figure-Ground relation and the type of caused motion than ‘put’ verbs. When considering syntactic patterns, more instances of asymmetry between these two event types show up. The analysis presented here supports the proposal that an asymmetry exists in the encoding of goals versus sources as suggested in Nam (2004) and Ikegami (1987), but it calls into question the statement put forward by Regier and Zheng (2007) that endpoints (goals) are more finely differentiated semantically than starting points (sources).

Abstract

Neste artigo fazemos uma revisão breve de investigações actuais com técnicas comportamentais e de neuroimagem funcional sobre a aprendizagem de uma linguagem artificial em crianças e adultos. Na secção final, discutimos uma possível associação entre dislexia e aprendizagem implícita. Resultados recentes sugerem que a presença de um défice ao nível da aprendizagem implícita pode contribuir para as dificuldades de leitura e escrita observadas em indivíduos disléxicos.

Abstract

Literacy and education represent essential aspects of contemporary society and subserve important aspects of socialization and cultural transmission. The study of illiterate subjects represents one approach to investigate the interactions between neurobiological and cultural factors in cognitive development, individual learning, and their influence on the functional organization of the brain. In this chapter we review some recent cognitive, neuroanatomic, and functional neuroimaging results indicating that formal education influences important aspects of the human brain. Taken together this provides strong support for the idea that the brain is modulated by literacy and formal education, which in turn change the brains capacity to interact with its environment, including the individual's contemporary culture. In other words, the individual is able to participate in, interact with, and actively contribute to the process of cultural transmission in new ways through acquired cognitive skills.

Abstract

For the beginning language learner, communicative input is not based on linguistic codes alone. This study investigated two extralinguistic factors which are important for infants’ language development: the type of ongoing shared activity and non-verbal, deictic gestures. The natural interactions of 39 caregivers and their 12-month-old infants were recorded in two semi-natural contexts: a free play situation based on action and manipulation of objects, and a situation based on regard of objects, broadly analogous to an exhibit. Results show that the type of shared activity structures both caregivers’ language usage and caregivers’ and infants’ gesture usage. Further, there is a specific pattern with regard to how caregivers integrate speech with particular deictic gesture types. The findings demonstrate a pervasive influence of shared activities on human communication, even before language has emerged. The type of shared activity and caregivers’ systematic integration of specific forms of deictic gestures with language provide infants with a multimodal scaffold for a usage-based acquisition of language.

Abstract

This paper explores the semantics of placement and removal verbs in Ākhoe Hai om based on event descriptions elicited with a set of video stimuli. After a brief sketch of the morphosyntax of placement/removal constructions in Ākhoe Haiom, four situation types are identified semantically that cover both placement and removal events. The language exhibits a clear tendency to make more fine-grained semantic distinctions in placement verbs, as opposed to semantically more general removal verbs.

Abstract

This paper identifies four reciprocal construction types in Khoekhoe (Central Khoisan). After a brief description of the morphosyntax of each construction, semantic factors governing their choice are explored. Besides lexical semantics, the number of participants, timing of symmetric subevents, and symmetric conceptualisation are shown to account for the distribution of the four partially competing reciprocal constructions.

Abstract

A aquisição de competências de leitura e de escrita pode ser vista como um processo formal de transmissão cultural, onde interagem factores neurobiológicos e culturais. O treino sistemático exigido pela aprendizagem da leitura e da escrita poderá produzir mudanças quantitativas e qualitativas tanto a nível cognitivo como ao nível da organização do cérebro. Estudar sujeitos iletrados e letrados representa, assim, uma oportunidade para investigar efeitos de uma aprendizagem específica no desenvolvimento cognitivo e suas bases cerebrais. Neste trabalho, revemos um conjunto de investigações comportamentais e com métodos de imagem cerebral que indicam que a literacia tem um impacto nas nossas funções cognitivas e na organização cerebral. Mais especificamente, discutiremos diferenças entre letrados e iletrados para domínios cognitivos verbais e não-verbais, sugestivas de que a arquitectura cognitiva é formatada, em parte, pela aprendizagem da leitura e da escrita. Os dados de neuroimagem funcionais e estruturais são também indicadores que a aquisição de uma ortografia alfabética interfere nos processos de organização e lateralização das funções cognitivas.

Abstract

n applied linguistics (AL), researchers have always been concerned with second language (L2) learners' knowledge of the target language (TL), investigating the development of TL grammar, vocabulary, and phonology, for instance.

Abstract

This paper describes the syntax and semantics of reciprocity in the Central dialect of Rotokas, a non-Austronesian (Papuan) language spoken in Bougainville, Papua New Guinea. In Central Rotokas, there are three main reciprocal construction types, which differ formally according to where the reflexive/reciprocal marker (ora-) occurs in the clause: on the verb, on a pronominal argument or adjunct, or on a body part noun. The choice of construction type is determined by two considerations: the valency of the verb (i.e., whether it has one or two core arguments) and whether the reciprocal action is performed on a body part. The construction types are compatible with a wide range of the logical subtypes of reciprocity (strong, melee, chaining, etc.).

Abstract

One of the most conspicuous ways in which people distribute agency among each other is by asking another for help. Natural languages give people a range of forms to do this, the distinctions among which have consequences for how agency is distributed. Forms such as imperatives (e.g. ‘pass the salt’) and recurrent types of interrogatives (e.g. ‘can you pass the salt?’) designate another person as the doer of the action. In contrast to this, impersonal deontic statements (e.g. ‘it is necessary to get the salt’) express the need for an action without tying it to any particular individual. This can generate interactions in which the identity of the doer must be sorted out among participants, allowing us to observe the distribution of agency in vivo. The case of impersonal deontic statements demonstrates the importance of grammar as a resource for managing human action and sociality.

Abstract

The use of the imperative for requesting has been mostly explained on the basis of estimations of social distance, relative power, and entitlement. More recent research, however, has identified other selection factors to do with the functional and sequential relation of the action requested to the trajectory of the ongoing interaction. In everyday activities among family and friends, the imperative is typically warranted by an earlier commitment of the requestee to a joint project or shared goal which the action requested contributes to. The chapter argues this to be the primary use of the imperative for requesting in Italian informal interaction, and distinguishes it from other uses of the imperative that do not conform to the predominant pattern. These other uses are of two kinds: (i) secondary, that is, less frequent and formally marked imperatives that still orient to social-interactional conditions supporting an expectation of compliance, and (ii) deviant, where the imperative is selected in deliberate violation of the social-interactional conditions that normally support it, attracting special attention and accomplishing more than just requesting. This study extends prior findings on the functional distribution of imperative requests and makes a point of relating and classifying distinct uses of a same form of action, offering new insights into more general aspects of language use such as markedness and normativity.

Abstract

Human communication is often thought about in terms of transmitted messages in a conventional code like a language. But communication requires a specialized interactive intelligence. Senders have to be able to perform recipient design, while receivers need to be able to do intention recognition, knowing that recipient design has taken place. To study this interactive intelligence in the lab, we developed a new task that taps directly into the underlying abilities to communicate in the absence of a conventional code. We show that subjects are remarkably successful communicators under these conditions, especially when senders get feedback from receivers. Signaling is accomplished by the manner in which an instrumental action is performed, such that instrumentally dysfunctional components of an action are used to convey communicative intentions. The findings have important implications for the nature of the human communicative infrastructure, and the task opens up a line of experimentation on human communication.

Abstract

The present paper looks at semantic interference and gender congruency effects during bilingual picture-word naming. According to Costa, Miozzo & Caramazza (1999), only the activation from lexical nodes within a language is considered during lexical selection. If this is accurate, these findings should uphold with respect to semantic and gender/determiner effects even though the distractors are in another language. In the present study three effects were found, (1) a main effect of language, (2) semantic effects for both target language and non-target language distractors, and (3) gender congruency effects for targets with target-language distractors only. These findings are at odds with the language-specific proposal of Costa et al. (1999). Implications of these findings are discussed.