Preverbal Communication

    First draft of a chapter for J.G.Bremner and A.Fogel (Eds) Handbook of Infancy Research. Oxford: Blackwell

    March, 1999


    Andrew Lock
    School of Psychology
    Massey University
    Palmerston North
    NEW ZEALAND

    A.J.Lock@massey.ac.nz


Introduction

This would have been a short chapter 25 years ago. It would have said something about how the early and classic studies of infancy by, for example, Tiedemann (1787; see Murchison and Langer, 1927) and Darwin (1877) noted that infants were able to communicate by cries and gestures before they could talk. There would have been mention of McCarthy's classic review of language development in the first edition of Carmichael's Manual of Child Psychology, where she noted that:

It is quite generally agreed that the child understands gestures before he understands words and, in fact, that he uses gestures himself long before he uses language proper ... It has been claimed that words constitute substitutes for actual gross motor activity (1954: 521).
There may have been some mention of both the Gesell (1945) and Bayley (1969) developmental scales containing some items related to communication in infancy. And there might have been a note to the effect that Spitz (e.g., 1957) had contributed some interesting notes from a psychoanalytic perspective on how infants managed to convey 'yes' and 'no' through smiles and head shaking. And that would have been about the sum of it.


    Today, it is difficult to know quite how best to review the field in the space available here. The research literature is now massive, both at an empirical and theoretical level, and its sophistication is such that a number of projects exploring the robotic modelling of 'embodied cognition' are able to actively pursue the construction of machines that can build their own pre-verbal abilities for recognizing and reproducing the gestural actions of others, and to coordinate their attention onto objects so as to 'learn' about communication and 'how to learn' (e.g., Bonasso, Huber, and Kortenkamp, 1995; Ferrell and Scassellati, 1998; Kahn and Swain, 1995; Kozima and Ito, 1998).


    Technological advances in other areas have themselves been central to the growth of this research topic in general. Video is the primary example, in that it has allowed us to capture and replay events unfolding in real-time and 'real' environments. We now take video replays for granted, particularly of sporting events on television, along with instant statistics relating to the course of a game as it progresses. This familiarity tends to make us forget that quasi-portable video equipment only became available 25 years or so ago, and the ability to link video to on-line computer analysis is itself more recent still. Similarly, we tend to forget that theoretical and conceptual issues that are now taken-for-granted as legitimate and central to the questions current in the field - such as regarding infants as developing the ability to intentionally communicate - have a chequered history, and that the mere claim 25 years ago by an emerging generation of post-graduate students that they were concerned to discover how infants could 'learn how to mean' could send their professors into fits of apoplexy.


    This chapter cannot be a comprehensive review. Instead, it focusses on age-related changes during the preverbal period empirical areas of research - for example, turn taking, joint attention, and gestures (particularly the pointing gesture) - and two theoretical issues - the 'nature' of preverbal communication and the social construction of early abilities through adult-infant interaction.


Overview


    The course of preverbal communicative development is punctuated by 3 major transitions during the first year of life. The first of these occurs at around 2 months of age, when infants begin to engage communicatively with adults. This change is sudden - 'almost as clear a boundary as birth itself' (Stern, 1985: 37) - and is correlated with changes in other areas of the infant's abilities (see Emde and Robinson, 1979). The second transition occurs late in the 5th month of age, when infants, again quite suddenly, appear to lose their interest in face-to-face interactions with adults and become engrossed by objects that they can manipulate (Lamb, Morrison and Malkin, 1987; Messer and Vietze, 1984). The third transition is less clear cut, but occurs around 9 to 10 months of age, and involves the connecting up of the infant's interest in objects with their emerging grasp of the agentive abilities of other people. We begin to see 'real' communication emerging at this time, with infants starting to use their partners in order to achieve their goals. This third transition is associated with a number of newly-emerging abilities (see Trevarthen and Hubley, 1978: 221- 2) that appear to have a common developmental basis - a 'grasp' of their own and others agency - and the course that any particular infant now takes in moving forward to verbal communication will vary as the different areas of this grasp and their emerging representational abilities are elaborated and feed back into the elaboration of specific skills. It is perhaps this increasing multi-determindness of development from this time on that leads to this transitional point being a little less clear cut than the two previous ones. In all cases, however, changes in cognitive abilities as new biologically-determined 'bits of kit' come on-line suggest that maturational factors and the general course of growth are major underwriters of the changes we see in infant behaviours and actions.


    The most unclear temporal point for this entire topic of 'preverbal communication' is the time at which it might be said to end. There are two issues involved here. First, the individual differences between infants as to when they begin to 'talk' are large, such that any time during the second year of life could be regarded as 'normal'. But second, when does a communicative episode or item stop being 'preverbal' and become 'verbal'? How one answers this question is very important. On the one hand, a clear, operational definition could be regarded as an important topic to settle, for if the 'data' being studied are ill-defined, then the first stage of a scientific investigation is stymied. On the other hand, though, clear definitions can create artifactual developmental rubicons that then obscure the very processes of change that scientific investigations are seeking to understand. These are problems that will be returned to later in this chapter. What needs to be borne in mind until then, however, is that all of the phenomena being dealt with here are at root transitional rather than categorical ones: at the outset, infants are 'without speech'; by the age of 2 years, small increments in the different strands of their development have fed back-and-forth amongst themselves to endow them with the qualitatively different ability of being able to 'talk'.


1. Birth to 2 months


This first period of an infant's life is a very difficult one to get a scientific handle on. This is not to say that a large body of reliable findings have not been established as to the major faetures of this time, for it has. The problem, however, that has to be faced is threefold. First, as will be obvious when dealing with the development of communication, at least two partners have to be involved in the process. Thus, it is not immediately apparent what the most appropriate 'unit of analysis' is: individuals or the dyad they constitute. Second, 'communication' is a quite variable phenomenon. Some aspects of communication can be handled by a purely objective approach, and we can talk sensibly, for example, of communicative signals produced by individual animals that have become chained together to produce patterns of behaviours in which each stimulates the other to produce the stimulus for the next act, and so on (see, for example, almost any ethological study of animal courtship behaviours). Communication, at this level, is just the co-ordination of the activities of two individuals, and the question 'what does animal A mean when it does X?' is not one that need be asked. This is not the case, though, with respect to linguistic communication, which, at least, has intentional and meaningful aspects that go beyond a purely objective level of description and explanation. Which is the most appropriate strategy with respect to early human infant communication?


    Third, and related to this dilemma, is the question of subjectivity and intersubjectivity. Consider eye-contact. Do we, as adults, look at each others' eyes because we find them interesting objects, either in their own right or as sources of useful information, such as what the other person is looking at? Or do we see them as 'animated', and part of a channel of 'communion' as opposed to 'information'? This is a difficult issue if one approaches the study of eye contact from the perspective of a detached, objective observer. It is a very different issue if one acts in the role of a participant, interactive observer. Similarly, if one is interacting with an infant. Mutual eye contact is one of the most emotionally-charged and satisfying forms of interchange adults participate in with their young offspring. But what does the infant make of it? Is it similarly a satisfying sharing or communion of being for them, or adult eyes just very interesting things to look at, rather than into? These issues will be left for a later section. Here, the general course of communicative development will be sketched.


    A major achievement by the end of this period is that adults and infants come to share increasing amounts of time 'staring at each other'. There appear to be a number of developmental strands that contribute to this achievement. To begin with, newborn infants periodically, but briefly, show a transitory state of quiet or inactive alertness, which is a 'fragile and easily disrupted condition' (Wolff, 1987: 66). Infants have been reported to spend about 10% of their waking time in this state during their first week of life (Berg, Adkinson and Stock, 1973), and these periods increase in both frequency and length until they occupy around half of daylight waking hours in the third month (Wolff, 1987). This state is increasingly induced when distressed infants are soothed by physical contact with others (Korner and Grobstein, 1966; Korner and Thoman, 1970). Being able to maintain this state is clearly crucial to the infant and adult subsequently sharing and modulating mutual attention to each other.


    Second, an increasing 'control' by the infant over the 'components' of its states of arousal becomes apparent. Crying by newborns, for example, is not just a vocal activity, but a whole package of facial distortions, limb movements, changes in skin colouration and muscle tone, breathing patterns and hand-clenching (Wolff, 1987; Papousek and Papousek, 1977). The activity appears to be a species-specific response to distress, and the amplitude of crying conveys information about the infant's level of distress rather than any more specific information as to what the nature of that distress is. Anything more specific about what a cry might mean is a construction on the part of the adult (see, for example, Murray, 1985; Frodi, 1985; Zeskind, 1985; Zeskind and Marshall, 1988; Gustafson and Harris, 1990). The early developmental course of crying follows what Barr (1990) has termed a normal cry curve: it's frequency rises from birth to a peak during the second month, and then declines to a low level around 4 months of age. This turns out to be true even in cultures where, because of differences in care in comparison to those Western societies from which most of the data come, infants cry much more rarely. Konner (1976) reported that in !Kung San hunter- gatherer societies, where infants are held for 80% of the day and fed on average 4 times an hour, crying was quite a rare and brief event, and infant distress was detected by their parent more by movement than crying. Infants came to use cries just in 'real' emergencies. None-the-less, a reanalysis of the original data by Barr, Konner, Bakeman and Adamson (1991) found the same crying curve as in other studies. Thus, while it is clearly infants that cry, and that there is something endogenous to infants that determines their crying behaviour, the realization of this underlying developmental pattern is influenced by the social context within which it unfolds.


    A similar pattern holds true for sleep-wake cycles. Neonates appear to have particular endogenous sleeping rhythms, for example, but even as early as the second week of life these are beginning to alter so as to come more in line with the diurnal patterns of their caretakers. At a sub-diurnal level, periods of infant alertness come to overlap more and more with the adult routines of holding and talking to them (Sander, 1977; Chappell and Sander, 1979; Sander, Stechler, Burns and Julia, 1970). Sander comments (1977: 147) that it is through these early interactions that 'unique and idiosyncratic characteristics of exchange' develop that increasingly regulate the interactions of individual adult-infant dyads: endogenous rhythms become restructured around social ones, providing a patterned framework within which development proceeds.


    Third, other aspects of infant emotional expression are initially under more endogenous than exogenous control (Emde, Gaensbauer and Harmon, 1976). Very young infants produce the whole gamut of adult facial expressions (Oster and Ekman, 1978), sometimes on appropriate occasions such as when they taste sweet or bitter solutions (Rosenstein and Oster, 1988), but generally they do so out of any appropriate situational context. These expressions give no evidence that they are intended as communicative, but are just spontaneously produced. Infant vocalisations at this time are also accompaniments to other activities rather than under voluntary control. Major anatomical and neurological developments (both central and peripheral) are needed before sound production can be controlled. For example, as Kent (1981) has noted, the substrate required to control the 100+ facial muscles needed to modulate speech sounds is not in place until around 5 months of age. Similarly, the upper respiratory antomy of the young infant has a typically mammalian pattern in which the larynx is placed high in the neck enabling the air and food tracts to function independently and simultaneously (which reduces the chances of the suckling infant choking as a result of milk going into it's trachea rather than it's oesophagous). The typical adult human anatomy, where the larynx is descended in relation to the oesophageal opening and the air are food tracts are shared for a short distance in the throat, is not attained until the first year of life (Laitman and Reidenberg, 1993).


    Fourth, neonates can be described as being variously 'preadapted' to having their attention drawn to different components of the communicative systems they are immersed in. Emerging perceptual systems are selectively tuned (to use Richards (1974) phrase) to dimensions that form the characteristic constellations of objects and events in their social worlds. Stern (1977: 37) has termed this 'innateness once removed'. Thus, for example, infants may not initially be specifically attracted to human faces per se, but adult human faces presented to them in the real time of everyday life may be sites that condense the varied perceptual dimensions that are individually attractive to infants: contrast, organization, movement and multimodality. In addition, as with other mammals, infant auditory systems function categorically from the outset, making then well attuned to the distinctions that structure the speech sounds they are immersed in (e.g. Kuhl, 1987). In addition, the way that adults modify their social actions towards infants tends to be in ways that exagerate those dimensions that infants already find attractive, thus making them even more attractive to infants (e.g., Fernald (1991) for the characteristics of speech directed to infants; and Stern (1977) for facial expression and its rhythmic integration with sound and touch).


    Fifth, unlike older infants who are most attracted to novelty, young infants are most attracted to familiar events: 2-week-old breast-fed infants prefer the smell of their own mothers; within two days of birth neonates prefer their mothers' faces to those of other adults (Field, Cohen, Garcia and Greenberg, 1984; Walton, Bower and Bower, 1992); and because of what they will have heard most often in the womb before birth, they prefer the characteristic sounds and tempos of their mother's voice from the outset (De Casper and Spence, 1986). Note, though, that these kinds of familiar events are always varying in their specific occurences and manifestations. If they did not, then infants would habituate to them rather than find them so attractive.


2. From 3 to 6 months


Infants change quite dramatically at the end of their second month: they begin to become intensely interested in people, and they become very rewarding 'human' partners in the eyes of those who care for them (see, for details, Emde, Gaensbauer and Harmon, 1976; Fischer and Hogan, 1989). While this change is most likely rooted in maturational factors, it has a qualitative rather than purely quantitative flavour: infants present a different interactive 'feel' to adults who engage with them. This 'presence' arises quickly. The objectifiable changes that accompany it fall into four areas: alertness, gaze control, smiling, and cooing. Infants are now in a state of alert awareness for around 80% of their waking time (Wolff, 1987), and give the impression of being able to both select objects in their environment to attend to, as well as initiate interpersonal actions, rather than have their attention captured by external events. Eye movements are under better control (e.g., Aslin, 1987); the caretaker's eyes can be focussed on so that periods of sustained mutual regard become possible; and the distance over which co-ordinated interchanges can occur extends continuously outward, no longer only occuring only while infants are held (Papousëk and Papousëk, 1977).


    Facial expressions become more animated, and their timing synchronises with the shared properties of the visual and physical interactions they are engaged in, so as to leave the adult participant in no doubt that these expressions are part of their joint interaction with a human partner, rather than being merely random activities on the infant's part. Smiling, in particular, shifts from what has been termed endogenous to exogenous control, and is often directed to the adult with whom mutual gaze is being sustained ((Emde et al., 1976; Wolff, 1987). Trevarthen (1979) has called attention to the increasing movements of the tongue and lips of the infant during interactions, terming it prespeech, and Fogel and Hannan (1985) have noted how such prespeech can be accompanied by hand movements that adults also read as having an expressive content. In addition, the infant's repertoire of vocal productions expands, particularly the 'coos and goos' that are taken as characteristic features of infancy.


    Overall, infants of this age become much more attuned to the finer details of the adult's vocal and facial expressions, and especially so to the temporal patterning of these. It is these tempos that increasingly moderate the interpersonal meshing of affect for both partners, and these properties of their interaction begin to be clearly exploited by adults so as to maintain mutually enjoyable interactions with infants - 'baby talk', exaggerated facial expressions and the captivating of the infant's attention by exaggerating the temporal characteristics of 'conversation' are prime aspects of the flowering of what Papousëk and Papousëk (1987) term 'intuitive parenting'. At the same time, infants become increasingly active participants in determining the course of interactions, such that the patterning of social interchanges results from the moment-to-moment responsiveness of each partner to the other, rather than being imposed by one or the other. The basics of human communicative 'dancing' are in place by about 6 months of age. And then infants head off on a new tack: they become dominated by an interest in 'things' rather than people.


3. 6 to 9 months


Piaget (e.g., 1963/1936) was one of the first investigators to emphasise the importance of this three-month period in an infant's life. At the beginning of this time, what he calls 'secondary schemes' - aimed at objects rather than the infant's body itself (primary schemes) - make their first appearance, and these become co-ordinated around 3 month's later to produce what he considered as the first truly intelligent and intentional behaviours: infants begin to act in ways that strongly suggest they are doing one thing in order that a particular end might be achieved. What Piaget did not emphasise in his classic account was the impact this interest in objects has for the development of communication. This shift to objects initially ruptures the episodes of

mutual regard (Kaye and Fogel, 1980; Trevarthen and Hubley, 1978), but it simultaneously sets infants a new and crucially important problem: how to incorporate and recruit people to share in their interest in objects, or, more generally, the world that exists beyond the boundaries of their previous absorbtion in the microcosm of faces and voices. Where the ability to jointly focus on each other has already been achieved, the new challenges are to co- ordinate these separate attentions on an extraneous feature of the world; to be able to initiate these co-ordinations; and to be able to tell when these have not been achieved.


    From a communicative perspective, these are very important challenges, for mastering them must in some way underpin the eventual move to achieving reference, to be able to talk about a common world, which is a primary characteristic of human language. At the root of these challenges is a complicated problem of imaginative interpersonal geometry; to come to understand, for example, that another's emotional expression can be a comment about something that is happening outside of the expression itself; to be able to 'read' where another is looking so as to be able to locate and share in the event they are talking about, rather than to be clueless as to what is going on; to grasp that actions of self and other can 'point to' something beyond themselves, such that one doesn't look at another's fingers and hands when they point with them, but need to look in the direction they are indicating to share in what they are pointing out. These are not easy problems to solve, and human infants are almost the only organisms known to be able to master them (see below). This mastery is very much a joint achievement rather than individual one, with adults providing a framework for it. Adults provide a 'scaffolding context' (Bruner, 1975; Wood, Bruner and Ross, 1976) whereby they engage and sustain their involvement with infants-and-objects before infants can do this for themselves.


    What infants can actually do at this point in their lives is currently unclear. Butterworth (e.g., Butterworth and Cochran, 1980; Butterworth and Jarret, 1991; see also Scaife and Bruner, 1975), for example, argues that there is evidence that 6-9 month-olds act on the assumption that their own visual space is held in common with those they are interacting with, in that they can use the visual information of where adults are looking to guide their own looking as a general guide, but what they look at when they turn to follow another's gaze is not something they can work out from just observing the adult. Rather, they end up looking at something that 'stands out' as worth looking at in that direction when they orient that way, it being the 'ecological' features of the environment that act to complete the message that the adult is signalling. By contrast, Corkum and Moore (1995), find no evidence that infants of this age can follow another's line of regard, and that while this ability begins to come in around 12 months of age, it is still rudimentary and not fully formed until at least 15 months.


    While it is important to gather more data on what infant's can actually do in this period, I want to suggest that at this age it is the actions of the adult that are of the prime developmental significance. What I mean is this: if we take the central point from Piaget that infants learn through their actions on the world, then how the world they are learning about is structured becomes of major significance as to what they learn. A very crude framework for thinking about what is happening at this time is that there are some very important maturational changes going on with respect to the infant's psychological make-up at this time, such that a number of new capabilities come 'on-line' in the last quarter of the first year of their lives (see below). How these abilities are structured as they emerge, and what it is that they are put to work on, is crucially dependent on the raw material they both work on and are forged through. That is, it is not just the case that infants act on the world, but that the world itself is transacted to them in the way another presents it.


    Consider how an adult can interact with an infant whose interests are focussed on object-manipulation when the objects are part of a formboard into which the pieces can be fitted. If the pieces are in their places, then they can be difficult for a 7 month old to extract. But their hands and grip can be physically assisted by the adult's actions, enabling them to achieve their aim. If the pieces are not in their places, then getting them there is even more difficult (shapes have to be oriented and matched to places, for example). Putting pieces in places is not a goal these infants can likely even formulate. But they can achieve it if the adult places the piece in such a way that just by touching it it is likely to fall into its place. There are numerous reports in the literature that draw attention to the ways adult's, often seamlessly, structure the opportunities infants have for attending to and manipulating their environments (e.g. refs). In addition, it is important to remember that the actions of adults are themselves not just opportunistically forged in the changing possibilities their infants offer as they act on objects that afford different canonical actions (balls are for rolling and blocks are for stacking - not just sucking, for example) either. Rather, the momentary possibilities for where-to-go- next are themselves embedded in the form-conserving practices, techniques, plans, formats of the cultural sphere within which adults structure their own plans and intentions:

the very essence of cultural development is in the collision of mature cultural forms of behaviour with the primitive forms that characterize the child's behaviour (Vygotsky, 1981: 151).
While Vygotsky's point applies equally to earlier periods, it's importance is more apparent and critical as infants of this age begin to act with objects.


    Towards the end of this period, we begin to see glimpses of infants being able, in particular situations that almost appear to invite the occasional activities that can be seen, to show the first stirrings of a co-ordination between their previous person-oriented communication skills and at least their 'reactions' with respect to objects and events. For example, Trevarthen and Hubley (1978: 200) report for an infant called Tracey that, at 38 weeks,

Tracey and her mother banged hands on the table in alternation and tracey, while looking at her mother, grinned at the effect they produced.
But to begin with, as these indications of an emerging awareness of the agency of others become apparent, there are few indications that infants can properly integrate action on objects into their communicative interactions with adults. Tomasello (1995: 107-8) interprets the situation to this point thus:
prior to 9 months of age adult-infant simultaneous looking is either fortuitous, a case of onlooking [see Bakeman and Adamson, 1984], a case of alternating attention, or results from infant gaze following as a learned response in which an adult head turn is used as a discriminative cue that an interesting sight is to be found in a particular direction. There is no joint attention or any other indication that infants at this age understand others as intentional agents.


4. 9-12 months


At 40 weeks, Tracey's mother became an acknowledged participant in actions. Tracey repeatedly looked up at her mother's face when receiving an object, pausing as if to acknowledge receipt. She also looked up to her mother at breaks in her play, giving an indication of willingness to share experiences as she had never done before (Trevarthen and Hubley, 1978: 200).


9-12 month old infants also seems to be in a transitional phase in which their actions on the world, and the staged integration of these into their social interactions with their culture that intrude on their otherwise individual 'obsessions', start to bear fruit, enabling an active integration of infant, adult, object and intention into more deliberate actions. There is a lot going on during this time, and the changes that are reported in the infant's abilities are important in that, first, they evidence a qualitative shift in the character of their performance; and second, these changes in a number of abilities - for example, imitation (Meltzoff, 1988), conventionalised gesturing (Bates et al, 1979); social referencing (e.g. contributors to Feinman, 1992); giving and taking objects (Clark, 1978; Griffiths, 1954) - either severally contribute to the infant coming to understand that others are separate beings with intentions and attentions that may differ from those of their own, and which need to be brought into line with the goals of the infant if they are to accomplish their own intentions, or are themselves consequent upon that emerging understanding. Interactions become increasingly co-ordinated (Adamson and Bakeman, 1985), such that by the end of their first year infants undergo 'a revolution in their understanding of persons ... that is just as coherent and dramatic as the one they undergo at around their fourth birthday' (Tomasello, 1995: 104; see also Tomasello, Kruger and Ratner, 1993; Bates, O'Connell and Shore, 1987; Bretherton, 1992).


    The general course of development at this time is now quite well established in the literature. Around 9 months of age, infants begin to change their pattern of attention when interacting with objects and people simultaneously. Prior to this time, and infant will focus his or her attention exclusively on an object that they either want or have. In the first case, infants give the appearance of being 'frustrated' at their lack of success in reaching for an object, for example, and express that frustration while continuing to look at the object. The participating adult may act to give the object to the infant. But at around 9 months, infants begin to break their gaze in such situations away from the object to look back and for between it and the adult: assistance in the pursuit of intentions is recruited rather than fortuitously received (Bates et al., 1975, 1979; Lock, 1978, 1980). Similarly, actions in pursuit of direct goals start to become stylised and aimed at the goal of getting the adult to act on the infant's behalf. Desired objects can be 'requested', and interesting sights can be 'pointed' to so as to establish joint attention on them, and infants develop a number of, often idiosyncratic, gestures that can convey their desires (proto-imperatives) and interests (proto-declaratives) (Bates, 1976).


    Requests and 'referential' gestures appear to have separate roots. Requests develop first, and are usually styled, or iconised, from direct actions: a stylised reach or up-turned palm in the recruitment of assistance in obtaining an object (e.g. Clark, 1978; Bruner et al., 1982), or raising both arms so as to be picked up (Service, 1984), for example. To begin with, these gestures are tied very closely to their immediate context of occurence and only later extend beyond this as the infant's abilities to predict events increases. Thus, for example, a 9 month old might arm-raise when confronted with indications that they are about to be picked up, whereas a 13 month old might anticipate being picked up because a meal is imminent and so indicate by arm-raising to a nearby adult in anticipation of needing to be moved to their chair. Similarly, the distance over which objects can be requested also increases (Bruner, Roy and Ratner, 1982; Werner and Kaplan, 1963), as can the specificity of what is being requested by an increasing repertoire of stylised actions that can be recruited for the purpose of specifying what is intended (for example, using a twisting motion of the wrist and hand to specify 'open this jar for me').


Pointing becomes productive later than requests, at around 12 months. Despite an increasing number of studies of this gesture, its actual developmental origins are still unclear. Some have argued (e.g., Vygotsky, 1966; Werner and Kaplan, 1963) that it is an abbreviated reach; others (e.g., Bates, 1976; Leung and Rheingold, 1981) that it is originally an action for the self, enabling an infant to better keep their own attention on an object, and that this only later becomes imported into directing the attention of others; and others that its origins are to be found in direct object exploration using the index finger, and all that happens developmentally is that this exploratory action is called into play with respect to objects that are just out of reach, and so it socially functions by default to direct another's attention, later becoming controlled by the infant for this purpose. Yet others have argued that the gesture is likely innate, since it has been regarded as a species-specific characteristic of humans alone (e.g., Butterworth, 1995), while further, some have claimed it is learned by imitation. There is now some evidence that it is a gesture that is used by chimpanzees, especially those with a deal of experience with human social interaction, and so it is not truly a unique species characteristic of humans (Leavens, Hopkins and Bard, 1996; Leavens and Hopkins, 1998). However, the fact that this has taken so long to be reported after so many hours have been put into studying primates in the past 30 years - studies which have clearly demonstrated 'request' gestures of various sorts - suggests that pointing does not come easily to non-human primates, and that divorcing 'desires' from objects into just wanting to 'say something' about an object, event or where one is looking is that much more difficult to achieve than requesting. (Note also that humans are additionally adapted to be 'attention directing organisms' by the colouration of their eyes - unique amongst primates in having 'whites' to them which might well function to increase the detectability of another's gaze). We might also infer this from the fact that a number of breeds of domestic dog are very good at incorporating gaze checking into ongoing object games with their owners - looking from ball to owner to ball - and can use objects as props to specify their desires - bringing leads to go for a walk or dishes to get fed - but do not 'point' so as to direct attention to interesting events, nor comprehend pointing gestures either (rather, they look at or sniff one's fingers). Pointing does appear to have a separate origin from request gestures, and is most likely rooted in attention directing rather than trying to gain contact with objects, with other factors fitting into providing the foundations for the mature performance of the act (for example, the anatomical configuration of the human hand predisposes the use of the index rather than any other finger for the actual performance of a point - see. for example, Lock, Young, Service and Chandler, 1990; Povinelli and Davis, 1994).


    Developments during this time have been theorised as arising in different ways. Cognitive explanations have tended to be either inspired by the Piagetian notion of a fundamental reconfiguration of cognition that informs action in many different spheres (e.g, Adamson, Bakeman and Smith, 1990; Fischer and Farrar (1988), or by developments occurring separately in different domains that in concert establish a base for a new emergent ability that capitalises on the achievements in the developmental strands that enable it. Bates and her colleagues (e.g., 1979) found that measures of an infant's abilities with respect to conventionalised communicative abilities, imitation, tool use (an index of the infant's understanding of means-end relations), object permanence and spatial relations were independent of each other at any particular age for infants in their study, but that the measures for the first 3 at the earlier ages were predictive of the time of emergence of productive symbolic communicative abilities at a later age. This makes intuitive sense in that to use a conventional 'word' requires one to know how to communicate, know how to reproduce (imitate) a conventional sound, and to have abstracted that sound out of the flow of speech one is immersed in (abstraction being integral to the mastery of means-end relations).


    By contrast, Trevarthen (1988) argues for a genetic base to the emergence of intentional communication, taking the view that there is a real difference in the nature of understanding the causal world of objects and the intentional nature of people, and that the basis for this latter understanding is built into the design of the developing human brain which is anatomically partitioned from the outset into 3 modes:

These modes are probably three real systems of the brain that achieve functional differentiation by interaction with each other and with the environment. Forms of action and perceptual processing appropriate for (1) knowing and using objects (praxic mode), for (2) communicating with the human world (communicative mode), and for (3) acting in a self-directed or thoughtful manner (reflective mode) appear as distinct rudiments in the newborn (Trevarthen and Hubley, 1978: 213).
It is the maturation of these systems, and the consequent possibilities for the integration of the developing 'contents' that accounts for timing of the emergence of new levels of communicative competence. The evidence consistent with this claim is that there are detectable changes in cortical functioning that correlate with the timing of the changes noted thus far in the first year of life (e.g., Thatcher et al, 1987); cortical maturation correlates with the onset of new, apparently modular, abilities (e.g., Baron-Cohen, 1995); the universality of the timing of these shifts cross-culturally (e.g., Trevarthen, 1988; Bakeman et al., 1990); and Bruner's trenchant question (1995: 2):
could any infant, or anybody for that matter, ever learn from scratch, from experience alone, that somebody was looking at something, and it was the same thing the infant was looking at? You would somehow have to know a priori that somebody was looking at something before it would occur to you to figure out what they were looking at.
Thus, Trevarthen posits an innate intersubjectivity:
This function identifies persons, regulates motivation and intention toward them, and simultaneously forms rudimentary acts of speech and gesture in patterned combinations and sequences It also provides internal images of face and hand movements for the identification and imitation of the expressions of others (1978: 213).


    It would seem most likely that both cognitive achievements and maturation are integral to these changes in infant abilities, and that the course of development in any particular child is determined by the unique constellation of events that child's maturing 'wetware' has available to it in the course of it's structural - and hence functional - differentiation. One such account is the dynamic systems perspective (e.g. Fogel, 1990; Thelen, 1989; Thelen and Smith, 1994; van Geert, 1991). Clearly, one thing that we do know beyond doubt from the intensive work on infancy in the past 40 years is that single factor explanations are wide of the required mark. This realization enriches our conception of these early developmental processes, but at the same time makes the 'telling of a normative tale' as to the actual course of development that much more difficult, for there is no one way in which infants might go on to 'crack the symbolic code'. Rather, there are lots of individual trajectories that can be traversed to reach a successful outcome (Nelson, 1996).


    That said, however, we can expect, at the end of this period, that is, around the infant's first birthday, to find ourselves confronted by a sophisticated communicator who as yet cannot use language, but who can, amongst other things: execute intentions alone and in harness with others; co-ordinate objects and people together in pursuit of these intentions; use gestures to partly specify these intentions (see below); can subordinate their own actions to the regulatory control of a limited number of another's words; can voluntarily give, take and request objects in interaction with others; has 'fined down' some control of their own repertoire of sound production; and who is on the verge of the symbolic realm, being able, for example, to use objects inventively to 'stand for' other objects in pretend play and to reproduce others' actions over long time delays (deferred imitation).


5. Developments in the second year


Consider the episodes captured in Figures 1 and 2, which portray a 12 month infant deploying all the skills she has amassed during her first year of life so as to very clearly convey to another what she wants: in one case an apple, in the other 'more to drink'. How does she go from here into 'language'? On the one hand, the apparently simple task of offering a description of the schedule of changes that we can expect to occur, has proved more difficult to arrive at than might be expected. On the other hand, the much more difficult task of explaining how language is arrived at has proved to be just that: much more difficult.


The schedule of events


In the beginning was the word" is exactly wrong; in the beginning was the utterance" (McShane, 1980: 1).


Water-tight definitions of what words and reference are have proved to be elusive. This makes a simple story such as the following at once useful and inadequate. Infants begin to use single words around the start of their second year of life (giving references here would be superfluous). Their vocabularies increase slowly at first, with only a few items added each month. Gestures tend to co-occur with utterances at this time, and seem to act in concert with what is spoken (Zinober and Martlew (1986): a point, for example, serves to identify the object that is simultaneously named. Gestures tend to outnumber words in the first part of the second year, but after that vocal signs become more dominant (Iverson, Capirici and Caselli, 1994). The shift from gesture to words is probably the result of the verbal envelope of everyday social life that infant development is immersed in, there being little evidence that infants are predisposed to favour vocal over manual production, or vice versa (Bates et al, 1979). Somewhere towards the middle of the second year, a rapid increase in the rate of development sets in (e.g., Halliday, 1975; Nelson, 1973). A number of the early investigators (e.g., Stern and Stern, 1907; Moore, 1896) as well as more recent ones (e.g. McShane, 1980) argue that it is at this point that infants gain the insight that words name or refer to things, and that armed with this principle they can learn new words more rapidly than by building up more laborious individual sound-object associations. Gestures now seem to accompany utterances as complements to 'words': that is, a point may single out an object that something can then be said about (Zinober and Martlew, 1986). By the end of their second year, children (they are not infants anymore) are combining words together in predictable and regular ways, and these regularities can be captured in simple rule systems. Whether these rule systems are productive or descriptive of the child's output is not settled at this point, and neither is the question of whether the regularities found in child speech at this age are generated by the same mechanisms that have been claimed to later underwrite 'true' grammar.See footnote 1 Gestures become much less frequent in the language activities of hearing children from the age of two, and the burden of 'making meaning' falls on words, their ordering, their intonation and their emphases.


    Most researchers would probably accept this story as a reasonable generalization, and there are both studies with large numbers of subjects (e.g., Bates, Bretherton and Snyder, 1987; Caselli et al, 1995), and also compilations across studies of the period (e.g., McCarthy, 1954; Reich, 1986) that do suggest a set of 'average milestones' . But the problem with it is not just that we need to add provisos as to individual differences amongst infants as to how this sequence is actually played out developmentally (for example, Nelson (1973) has characterized two broad styles of early language development - referential and expressive: referential infants tend to show a vocabulary spurt as described above; expressive children do not). Rather, and in contradiction to the claim that the above is a reasonable generalization, there is in fact quite a lack of agreement amongst different researchers as to the nature of early speech: for example, Dale (1980) finds naming to be the earliest appearing form of speech, whereas Halliday (1975) finds no evidence of naming at all for the child he studied during the same period. There are a number of reasons why this could be the case. First, there are marked individual differences amongst the children whose language development has been studied. From these differences we need to note that:
         1. The view that there is a universal sequence of stages is a myth. Elucidating the way in which this myth has been constructed and interwoven with theoretical claims as to the innate bases of language in humans - claims which have then become categories that mould the data to fit them - would make for a paradigmatic case study in the history of science ; and
         2. It is more likely that language emerges from a system of underlying competencies (e.g., van Geert, 1991; cf above on dynamic systems approaches), and that any biological imperatives are of a general nature that make 'language' of salience to infants (Bates and Carnavale, 1993), rather than depending on a single module or suite of modules.


    Second, different researchers use both different coding schemes and different theoretical perspectives, and these can make comparisons between studies and the drawing of generalizations from them very difficult. Third, and perhaps the major problem, is that there is no clear definition of the boundaries of what constitutes meaningful and conventional language. This last problem is crucial. It might reasonably be thought that little progress can be made without clearly defined operational categories. However, such categories, in setting up Rubicons that must be attained can fundamentally obscure the nature of development in this period: and theoretical convenience should not act so as to mask the nature of developmental processes of change over time. It is unlikely that there exists in the infant at any point in time a definable cognitive system for us to discover. We should not ask, for example, 'what does the infant mean when he or she says 'doggie'' with the hope of uncovering the semantic features of this word that are represented in the infant's mind. Rather, we should be asking questions such as: 'What might the infant be on the way to meaning when saying such a thing? What might the infant taken to be meaning by an adult in saying this, and how is the 'acting out' of this interpretation 'responded to' by the infant?'. We need a more adequate framework within which to locate our understanding of changes during this period.


Towards a more adequate theorisation of early communicative development


What might we need by way of a theory to deal with these changes in infancy? This is dangerous speculative territory, but I offer the following suggestions none-the-less. For a number of reasons, the fact that all our psychological abilities work in concert to provide us with an experience of being-in-the-world has been under emphasised in contemporary psychological science, to the point where we tend to forget that this is the case. We have been committed to a rigid division of the objective from the subjective through adopting the methodologies of sciences which study the environment from the position of a detached, disembodied observer whose senses are augmented by prosthetic devices (La Barre, 1954; Bruner, 1966) that allow us to sense worlds otherwise hidden from us, and have forgotten that the environment is different from our environment. I suggest that there are a number of strands of work that provide the outlines of a potential framework that allow us to get back to where we really belong.

1. Katherine Nelson has recently (1996) recognised one of the steps we need make:

 'it is necessary for psychologists to understand the nature of the child's experience at different points in development. This requires in part the specification of the environment, as in ethological and ecological studies; it requires as well, and specifically, an effort to understand the perspective of the experiencing individual (1996: 10).

However, while endorsing this stance on Nelson's part, I am leaving aside the particular framework within which she goes on to develop her discussion once she has made this shift: that is, as a framework within which to better elucidate the ways in which a child comes to represent the world


2. The framework of 'embodied cognition' that has emerged in current artificial intelligence and robotic science provides a second strand, in that it allows us to get away from the problems inherent in disembodying knowledge as symbolic representational mental systems, and reunites 'mind and body, world and action' (for a review, see Clark, 1996). What we find here is a framework that enables us to 'dump' a great deal of the information required for the control of ongoing action back into the environment, in a sense using the objects in the world as the best representations of themselves as a scaffold for our own effective, behavioural environments.


3. Once we have distributed 'intelligence' back into the mutually supportive and constitutive relationship between form and environment, then we can pick up on two related concepts separately stated by Macmurray (1961) and Vygotsky (1966). First, Macmurray's view is that the human infant:

is not an independent individual. He lives a common life as one term in a personal relationship. Only in the process of development does he learn to achieve a relative independence, and that only by appropriating the techniques of a rational social tradition. ... The unit of the personal is not the 'I', but the 'You and I' (1961: 50, 61).
    Vygotsky's take on this is his insight that:
Any function in the child's cultural development appears on the stage twice, on two planes, first on the social plane and then on the psychological, first among people as and intermental category and then within the child as an intermental category (1966: 44).

    Putting these points together enables us to grasp how the 'sense' that infants come to find in the events that make up their perceptual world is structured not just by their own actions, but by those of others. In this sense, 'making sense' of the world is accomplished communicatively, and objects and events come to be known on their reappearance in the infant's perceptual field for what they can do: properties are constituted as intrinsic to objects and events through their social nature as 'props' in the interactive acting out of intentions.


    As an analogy for this suggested 'way of looking' at the problem, consider the random dots in Figure 3. Unlike the famous reversing figure-ground images beloved by Gestalt psychologists, once one has 'seen' the Dalmation dog in the pattern one cannot go back to seeing it as a random collection. This, I suggest, is what happens to objects and events the infant encounters: these come to present themselves differently to the infant's immediate perception of them as they come to have more and more 'affordances' structured into them.


    A more precise way of dealing with these changes, particularly from the point of understanding the course of communicative development, is to theorize the infant as involved in uncovering the implicit properties of their actions in the world (e.g., Lock, 1980; 1997). These implicit properties have been made explicit by previous generations and are part-and- parcel of the cultural system infants grow up in. One cultural rendering we could give to Figure 1 is that the infant means 'I want you to give me that apple'. The infant controls this implication in her actions. She began by gaining control of lower level implications: knowing what she needs she will reach for an object, but only post 9 months of age will she come to control the implication that 'if I want that, and can't reach it, then you must give it to me', and we start to see her 'appealing' to adults for assistance. And only very late in the play will she bring out for herself an explicit marking of her implied existence: post the attainment of symbols and propositions, she will 'assume' her self, a self that has been there as an object of others acts to and with her, but not constructed as something that can be talked about until language is in place.


    Preverbal communication can thus be seen as a period in which the infant is coming to control the implications of his or her situation in the world. Their developing biological and psychological 'mechanisms' are simultaneously structured by the perceptual environment they constitute as the infant's emerging experience or Umwelt. As new bits of 'kit' come on line, infant's are therby enabled to grasp, in an ordered fashion, the implications of their situation. The nature of communicative development is best captured by (a) describing it as the 'coming to control' of the implications of being an infant; and (b) explaining it as an interplay between emerging 'wetware' and the socially-mediated experiential world that this wetware underwrites.


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Notes


Footnote: 1 On this latter point, for example, it is now clear that under particular circumstances both species of Pan can use words in as complicated ways as human 2 year-olds. It is less certain that Pan individuals go beyond this level. It could be that species other than humans lack a set of organizing resources for language that 'come on-line' in humans around the age of two, and that these early word combinations have nothing truly linguistic about them in their structural aspects at all. On the other hand, it could be that a linguistic organizer comes in quite early for human infants, and our two word utterances are not homologously generated as compared with those of other species.