Example 1: increased rhythmic arm movement coincides with the onset of reduplicated babble
In a longitudinal study of rhythmic motor stereotypies in typically developing infants during the first year of life, Thelen (1979)
reported a striking peak in frequency of rhythmic arm movements (e.g. shaking, swinging, banging) at around twenty-eight weeks of age. This is also the age at which many infants begin to produce reduplicated babble, vocalizations in which well-formed syllables are organized into a regularly timed, rhythmically organized sequence (e.g. [bababa]; Koopmans-van Beinum & van der Stelt, 1986
; Oller & Eilers, 1988
Several longitudinal studies have explored the nature of the relationship between rhythmic arm activity and onset of reduplicated babble by following infants from the pre-babble period through the onset of reduplicated babble. In the first of these, Eilers, Oller, Levine, Basinger, Lynch & Urbano (1993)
followed infants from the second month of life, with regular laboratory observations occurring every two to four weeks. Parents reported the onset of rhythmic hand banging and reduplicated babble, and behavior onset was credited when an experimenter confirmed the parent’s report via observation during a subsequent lab visit.
Results indicated that the mean age of onset of rhythmic hand banging preceded that for reduplicated babble by two to three weeks. Although no correlational analyses are presented and the extent to which this pattern was apparent in individual infants within the sample is not described, these data suggest the possibility that hand banging may present an opportunity for practicing the production of rhythmically organized, tightly timed actions of the sort required for babbling. Specifically, hand banging produces highly redundant, multimodal feedback that facilitates infants’ growing awareness of correlations between their own movements and resultant sound patterns. When infants engage in rhythmic banging, they feel themselves move, they see the movement of their arms, and they hear the resultant sound, all occurring in synchrony. The extensive literature on multimodal perception in young infants (see Lewkowicz (2000)
for a review) suggests that infants are highly sensitive to this type of synchrony, and that the presence of such redundant cues facilitates recognition of contingencies (e.g. Gogate & Bahrick, 1998
; Gogate, Bolzani & Betancourt, 2006
). When infants subsequently begin to babble, they may very well be better prepared to recognize the contingent auditory feedback from their own sound production, feedback that allows them to monitor and adjust the state of the vocal tract as they vary their sound production.
Support for this view comes from three longitudinal studies that have taken a milestone-based approach to the relationship between rhythmic arm movement and reduplicated babble (Ejiri, 1998
; Iverson, Hall, Nickel & Wozniak, 2007
; Locke, Bekken, McMinn-Larson & Wein, 1995
). In all of these studies, infants were given rattles to shake, their rattle-shaking was observed in sessions prior to, at and following the onset of reduplicated babble, and changes in rhythmic arm activity were examined as a function of time relative to babble onset (i.e. without regard to infant chronological age). The consistent finding was that rhythmic arm shaking was lowest in pre-babbling infants, increased sharply in infants who had just begun to babble, and then began to decline as infants became experienced babblers. This pattern (distinct time of onset, peak and decline) parallels that of developmental trajectories observed for other rhythmic stereotypies (Thelen, 1979
). Thus, for example, infants rock on all fours before they crawl and wave their arms before they reach; and once these milestones have been attained, rocking and arm waving become less frequent. On this view, once infants have begin to babble, rhythmic arm activity may have accomplished at least part of its developmental task – providing infants with a rich sensorimotor context for practicing skills that underlie (at least in part) the production of reduplicated babble.
The close temporal relationship between reduplicated babble and rhythmic arm activity is often interpreted as indicating that babble is one of a family of rhythmically organized motor stereotypies that emerge and are commonly produced by infants during the first year of life (e.g. MacNeilage & Davis, 2000
; Kent, 1984
; Iverson et al., 2007
; Meier, McGarvin, Zakia & Willerman, 1997
) and as evidence of a tight, specific link between the manual system and the oral–vocal system (e.g. Iverson & Thelen, 1999
). The data reviewed above suggest a third, complementary interpretation of this relationship, namely that skills observed in rhythmic arm activity are shared by reduplicated babble. As infants perform rhythmic arm movements, they have the opportunity to practice a skill – production of rhythmically organized, tightly timed actions – that is a central characteristic of reduplicated babble. Hand banging provides a supportive context for the development of this skill because it provides multimodal feedback that allows the infant to observe (and vary) the relationship between a concrete action and its auditory and visual properties.
Example 2: developments in object displacements in play are related to first words and the vocabulary spurt
Lifter & Bloom (1989
; see also Bloom, 1993)
conducted a longitudinal study of the relationship between language and object knowledge, as indexed by object displacements in spontaneous play. They focused specifically on identifying developments in play and their relationship to the emergence of specific object knowledge, i.e. of the perceptual and functional attributes that differentiate objects from one another. They reasoned that the extent to which children’s actions with objects took account of specific properties of those objects provided a source of information for inferring the object-specific knowledge that underlies the formation of the object concepts necessary for talking about objects and events. Once again, however, it is important to note here that the development of action on objects depends not only on cognitive gains but also on gains in motor skills such as unilateral reaching, use of a pincer grip, finer eye-hand coordination, and independent use of the hands and arms in relation to one another.
In their longitudinal study of infants seen monthly between the ages of 0;8 and 2;2, Lifter & Bloom (1989)
examined object displacement activities, defined as actions in which infants moved one toy in relation to another (e.g. dropping a bead into a container, putting one nesting cup into another, feeding a doll with a spoon) ‘with deliberate volition to achieve the action’ (p. 399). The primary criterion for ‘volition ’ was that the infant had to orient to the object first and then act on it ; success in achieving the target action was not considered in this coding decision, but random encounters with objects (e.g. accidentally dropping a bead into a box) were ignored.
Once object displacements had been identified, an initial distinction was made between those that were separations, involving disassembly of a complex object into components (e.g. taking a peg person out of a seesaw), and those that were constructions, involving assembly of a more complex object out of components (e.g. putting a peg person into a seesaw). Constructions were then subclassified according to whether or not they: (a) were imposed by the child and differed from those originally presented by the researchers (e.g. putting a peg person into a nesting cup); and (b) made use of particular properties of objects in relation to one another (e.g. stringing beads; feeding a doll with a spoon).
Developments in language were tracked by transcribing word use at each session and identifying the ages of onset of first words (i.e. the session at which one conventional word was used at least twice) and the vocabulary spurt (i.e. the session at which twelve new words had been added since the previous visit, after reaching a baseline of twenty words) for each child. This permitted the examination of developmental changes in action on objects in relation to both chronological age and language level.
There was a clear developmental progression in infants’ action that was closely linked to achievements in language. During the prespeech period, the vast majority of infants’ object displacements involved taking things apart. With the advent of first words, however, putting things together not only became progressively more frequent, but children also began to put objects together in ways that they had not previously seen them combined (e.g. putting a bead inside a nesting cup rather than putting one nesting cup inside another). During the vocabulary spurt, constructions began to make use of specific features rather than generic characteristics of objects (e.g. putting a bead on a string rather than simply placing the bead inside a nesting cup). This developmental progression in action on objects and its association with achievements in language was observed in all of the children despite substantial individual differences in rate of language acquisition. Bloom (1993)
has argued that this parallelism reflects common developments in underlying cognition, specifically changes in object concepts and advances in the ability to access this knowledge for actions with both objects and words.
While Bloom’s (1993)
interpretation makes excellent sense, it is important to reiterate that these common developments in underlying cognition themselves depend on advances in infant capacity for action. Infants in this study began by engaging primarily, if not exclusively, in separating objects. Separating is a relatively simple motor task: it only requires the infant to grasp one object and pull at it to make the configuration come apart. Although objects can, in principle, be immediately put back together once they are separated, Lifter & Bloom (1989)
note that at this early object separation stage infants generally did not do so; rather, it was mothers who often reconstructed the configurations so that the infants could separate them again. They also point out that as infants repeatedly take constructions apart, they learn about the separateness of objects and that objects can be joined together; in other words, that ‘[l]earning how to construct a relation begins with learning how to take it apart’ (p. 414).
In short, the emergence of constructions indexes two closely related progressions in infant action. The first is the recognition that things go together, indicated in the context of action by placing them in physical relationship to one another (e.g. a bead can be put in a nesting cup). The second, and perhaps even more fundamental recognition, however, is that actions are reversible; in other words, that the bead that can be dumped out of the nesting cup can also be put back in it. Armed with these two new possibilities for action, infants can not only construct relations; they can also experiment with creating varying and novel combinations of constructions. Such an infant can now not only put a bead in a nesting cup and take it out, but then put it into a toy car, pick up a peg person and put the peg person in the now-empty nesting cup.
In the context of these play actions, the child has the opportunity to notice, attend more specifically to, and learn about progressively more specific properties of objects. Thus, in creating different constructions involving nesting cups and beads, the child might notice the fact that the nesting cup can serve as a container for many different toys and that the bead has a small hole in it. In other words, in the course of putting toys together and observing the consequences of these actions, children begin to link objects with meanings created in the context of their actions, i.e. the nesting cup is a container. The ability to connect meaning with a referent is, of course, fundamental for word learning.
Finally, as children notice progressively more specific characteristics of objects – that, for example, the bead has a small hole in it – opportunities for more refined actions on those objects are created. When the child notices that the hole in the bead is similar in diameter to the string, she might attempt to put the bead on the string. Even if this action is unsuccessful and the bead falls off the string, the physical attempt to create this highly specific construction provides an opportunity to give additional meaning to the bead: where it was previously something to be put in a container, it is now something that can also be strung. As Bloom (1993)
suggests, the increasing specificity observed in children’s object constructions over time provides evidence of development in the ability to attribute mental meanings that are increasingly varied and elaborated. The critical point here, however, is that these mental meanings – and their links with objects – are given in the context of developing physical action: playing with, manipulating and acting on toys in new and progressively more specific ways. These new forms of action depend in turn on developing motor skills.
To summarize, developmental progression in action on objects and achievements in early language development are closely associated, and intersections between these domains are traditionally interpreted as reflecting advances in common underlying cognition. A complementary perspective is that physical action on objects sets a context for attributing meaning to those objects via action. As infants act on objects in increasingly sophisticated ways dependent on increasingly sophisticated motor skills, they are presented with the opportunity to notice more specific object features. As they refine their actions further in order to make use of these features, they are able to attribute increasingly specific meanings to objects. This latter development is of particular importance inasmuch as learning words requires, among other things, the mapping of specific meanings to specific referents.
Example 3: the emergence of naming in action and language
A final example of correspondence between milestones in motor action and language is evident in work begun in the Piagetian tradition, pursued by Bates and colleagues (e.g. Bates et al., 1979
) during the 1970s and 1980s, and revisited most recently by Volterra and colleagues (e.g. Capirci, Contaldo, Caselli & Volterra, 2005
; Volterra, Caselli, Capirci & Pizzuto, 2005
). At issue in this work is a behavioral phenomenon frequently termed ‘recognitory gesture’.1
Recognitory gestures are actions that are brief, stylized versions of the actions typically produced on associated objects. For instance, when an infant between the ages of 0;9 and 1;0 first catches sight of a toy telephone among her play objects, she may pick up the receiver, touch it momentarily to her ear and then immediately set it down. Through this gesture, the child is, in effect, indicating recognition that she knows what the object is. Additional examples might include making a brief stirring motion with a toy spoon or touching a hairbrush briefly to the hair.
There are two indications that recognitory gestures are not simply a product of the infant’s attempt to imitate the prototypical actions that adults produce with objects. The first is that, unlike adult models for these actions (e.g. holding up the telephone receiver to the ear and talking), the infant version is, as indicated above, generally very brief and incomplete, lasting only two to three seconds. The second is that the recognitory gesture does not appear to be an attempt to satisfy a need; for example, an infant might pick up an empty cup and touch it briefly to the lips, not in an attempt to drink from a cup that contains no liquid but rather to show by means of the gesture that the cup is used for ‘drinking’.
The appearance of recognitory gestures marks an important transition in infant action. Prior to the emergence of these gestures, infants act on objects for the purpose of manipulating them. When an infant aged 0;7 plays with a toy telephone, he may shake the cord, bang on the base, mouth the receiver or run an exploratory finger over the buttons. Although these actions reflect growing sophistication in object manipulation, they are relatively generic and could, in principle, be applied to any number of different objects. With the appearance of recognitory gestures, however, comes evidence of an emerging ability to use action for the purpose of assigning specific meanings to objects. At 0;10, when an infant picks up the phone receiver and briefly touches it to her ear, she is not merely manipulating the receiver; she is reflecting her awareness that the object has a specific meaning, that it is, in other words, a telephone.
Recognitory gestures of this sort not only indicate the emergence of the infant’s ability to assign meaning intentionally, they also provide infants with a way of practicing meaning-making at a point in development at which they are just beginning to face the problem of using words to convey meaning. Furthermore, this practice takes place in a concrete context. Unlike word–referent links, which are generally highly abstract and require the child to pair arbitrary sound productions with meaning, the link between a recognitory gesture and its referent is relatively concrete. Meaning is assigned through a non-arbitrary action that produces immediate perceptual and proprioceptive feedback. Thus, for example, unlike the word phone, which bears no physical resemblance to its referent, the recognitory gesture ‘phone’ incorporates elements of the action (albeit in stylized form) that is typically associated with and conforms to the physical characteristics (size, shape, etc.) of the telephone. Furthermore, as the infant brings the telephone receiver to her ear, she feels the movement of her arm, the object in her hand, and ultimately the contact between the receiver and the side of her head. If a helpful adult is nearby, she may even receive some timely linguistic input: ‘That’s right, that’s a phone. Are you calling someone? Is that Daddy?’ At such moments, infants learn not only about action–referent mappings, but that they themselves are capable of making meaning, meaning that is appreciated by others in their environment.
In line with this view, Capirci et al. (2005)
recently observed that meanings that infants initially ‘practiced’ in recognitory gestures were highly likely to enter their communicative repertoires as representational (i.e. empty-handed) gestures and/or words. In a longitudinal study of three children, these investigators found that the percentage of semantic overlap (i.e. the percentage of items in the repertoire that conveyed the same meaning) between recognitory gestures and representational gestures and/or words ranged from 88% to 97.5% and that recognitory gestures corresponding in meaning with a representational gesture and/or a word generally appeared before the emergence of the corresponding representational gesture/word. In addition, as the authors note: ‘Almost all actions were produced by the three children in a situation in which the caregiver was present and was making comments and attributing meaning to the action performed by the child’ (p. 173).
The role of recognitory gesture in early symbolic development has been extensively discussed in the theoretical literature (Inhelder, Lézine, Sinclair & Stambak, 1971
; Piaget, 1952
; Werner & Kaplan, 1963
). A common theme in these discussions is that recognitory gestures are yet another manifestation of the emergence of a general symbolic capacity toward the end of the first year. Indeed, Escalona (1973)
has even argued that infants use recognitory gestures in much the same ways as they do first words: to identify, recognize, categorize or ‘name’ an object, event, or class of objects and events. For this reason, she refers to recognitory gestures as ‘enactive naming’ because, as Bates, Bretherton, Snyder, Shore & Volterra (1980)
have suggested, ‘infants seem to be using these schemes for a very different function than the one originally intended by the culture: to label a known object by carrying out an activity typically associated with that object’ (p. 408).
The most widely cited evidence for the view that recognitory gestures are a type of naming comes from longitudinal work carried out by Bates et al. (1979)
and Volterra, Bates, Benigni, Bretherton & Camaioni (1979)
. This research gathered detailed information about the vocal and gestural repertoires of twnety-five Italian and American infants between the ages of 0;9 and 1;1 and involved a combination of observational data and maternal report measures. They documented a series of close parallels in the development of recognitory gestures and first words. Two of these are of particular importance for the present discussion.
First, recognitory gestures and first words appeared in individual children’s repertoires at around the same time, though there was considerable variability in the ages at which they were first observed and the rate at which they emerged. In addition, they tended to refer to a common set of meanings: eating, dressing, playing with vehicles, telephones, games of exchange and peekaboo, bathing, and doll play. Indeed, there was considerable overlap in the content of the vocal and gestural repertoires when they were compiled across children. Interestingly, however, this redundancy was uncommon among individual children: it was not the case that each child who had a recognitory gesture for a given object also produced the corresponding word.
Second, over the course of the period from 0;9 to 1;1, both recognitory gestures and words underwent a similar process of decontextualization, progressing from initially highly context-bound productions to application across a broader set of contexts. Thus, for recognitory gestures, the following developmental progression was noted (see also Nicolich, 1977
- Briefly carrying out an object-related activity to recognize appropriate object use (e.g. briefly bringing a telephone receiver to the ear).
- Carrying out a familiar activity that is within the child’s existing repertoire, but outside of its usual context (e.g. ‘sleeping’ with head on the table).
- Carrying out actions with others in which child’s role is reversed (e.g. rather than feeding himself, the child feeds mommy or a doll) or that are typically associated with others (taking on an adult role; e.g. vacuuming, wiping the highchair tray with a cloth).
- Carrying out an action with a substitute object (e.g. using a spoon as a telephone).
In the course of this decontextualization process, infants apply action schemes across a widening range of contexts, to progressively more abstract objects, and to different recipients. This is suggestive of two major developments. First, production of recognitory gestures (and of meanings in general) becomes less reliant on contextual support. Thus, where the ‘phone’ recognitory gesture was once produced only in the presence of the toy telephone and was only self-directed, it eventually begins to be applied to other objects (e.g. using a spoon as a telephone) and to other individuals (e.g. holding the receiver to the doll’s ear). In other words, production of the ‘phone’ gesture no longer requires a precise replica of the conditions under which the action first emerged (i.e. during spontaneous play with the toy telephone).
The second development is that as infants gradually extend action schemes outside the original context of production, they begin to appreciate the fact that a common action and therefore a common meaning can be applied to a variety of different objects. An infant might, for example, assign ‘phone’ meaning by making the ‘phone’ gesture not only with the toy telephone, but also with a spoon, a rattle and a plastic banana.
Thus, production of recognitory gestures provides infants with opportunities to learn: (a) that meanings are context-independent; and therefore (b) that the same meaning can be assigned to different objects in different contexts. While objects and contexts may vary, a particular and specific meaning can remain invariant. This sets the stage for one of the most important advances in early language development, namely the recognition that because a given word can be used to refer to a range of referents (e.g. dog can refer to the family Saint Bernard, a pictured story-book chihuahua, and a Great Dane seen in the park), word meanings are both general and relatively specific. As infants begin to use first words, this is something that they must come to understand.
Understanding of this sort, however, develops only gradually. As Volterra et al. (1979)
have observed, first words, like recognitory gestures, also undergo a process of decontextualization. Infants’ initial word productions are highly context-bound and, more specifically, bound to particular actions and procedures with which they have been associated. In the Volterra et al
. data, most instances of early word use occurred as the child executed a specific action in a specific context. Thus, for example, bye-bye
was initially produced only when the child was putting down the phone receiver. At this point in development, the meaning of bye-bye
was something like ‘breaking contact while putting down a phone receiver’, a meaning both limited to a single context and given by reference to the entire context of action and object rather than to a specific referent.
As development proceeds, the infant extends bye-bye to contexts beyond that of hanging up the phone. With extension, meaning becomes not only increasingly context-flexible (e.g. bye-bye is now produced not only when putting down the phone receiver, but also when people are departing, when a toy disappears from sight and when someone is preparing to leave the house) but specific (bye-bye now represents breaking contact, regardless of the immediate context). Decontextualization of recognitory gesture, in which the child practices assigning common meaning in multiple and varying contexts, helps set the stage for this advance.
In short, during the period between 0;9 and 1;0, recognitory gestures and first words develop in both content and gradual decontextualization. Not only does this reflect the emergence of a general ability to symbolize (e.g. Bates et al., 1979
), it suggests that naming (both gestural and verbal) is born in motor action. Recognitory gestures provide children with the opportunity to practice ‘naming’, first by assigning meaning to an individual referent and then by extending a common meaning across a variety of different referents. Furthermore, and importantly, this prelinguistic ‘naming’ occurs in the domain of action in which the relationship between the action component of the gesture and the referent is both non-arbitrary and concrete. When children then begin to assign meaning using the arbitrary sound productions that constitute words, they can draw upon their experience with recognitory gestural naming to facilitate the acquisition of this new skill. It is therefore not surprising that first words are tightly bound to action and that children are highly likely to name objects as they act on them (Rodgon, Jankowski & Alenskas, 1977
; Volterra et al., 1979
) or that children’s early words tend to refer to small, easily manipulated objects (Nelson, 1973
; Bates et al., 1979