Target article: Michael Arbib

Word count

Abstract : 40

Main Text: 1118

References: 588

Entire text (title+abstract+main text+references): 1775

TITLE:

The first dialogue: ‘conversation’ through imitation with newborn infants

Emese Nagy

Department of Psychology, The University of Dundee, Nethergate, Dundee, Scotland, DD14HN

Phone: 44-1382-344613

e-mail: E.Nagy@dundee.ac.uk http://www.dundee.ac.uk/psychology/enagy/welcome.html

Abstract

I suggest that the ‘language ready brain’ proposed by Michael Arbib equips the newborn infant with the ability to effectively communicate by using imitation right after birth, and that language evolves – partly - from these early imitative reciprocal intersubjective ‘conversations’.

Michael Arbib presents an elegant neurolinguistic model on the phylo- and ontogenesis of language. He proposes that during the development of the mirror neuron system children have to acquire imitative ability, which is developed by childhood but not yet developed in infancy. Arbib, however, also postulates that infants already possess a language-ready brain and points out that language development is deeply embedded in very early social development.

I propose, that the language ready brain equips the newborn infant with the ability to effectively communicate by using imitation right after birth, and that language starts to evolve from these early imitative intersubjective conversations (Trevarthen, 1998; 2003) through an innate sensitivity to the rhythm (Pettito et al. 2001), basic properties, and musical qualities of the language (Ramus et al, 2000).

The cognitive developmental approach in the first half of the 20^th century (Piaget, 1962) assumed that imitation of observed actions occur at the earliest from 10-12 months of age. A series of studies from the 1970es however, reported that infants as young as a few hours old could imitate variety of behaviours such as mouth, tongue, eye, hand, arm and leg movements (Maratos, 1973, Meltzoff and Moore, 1977, Kugiumutzakis, 1993). Despite these findings however, neonatal imitation remained a controversial ‘fuzzy phenomenon’ (Heimann, 2001) by experimental psychologists, was even regarded as artefact by others (Anisfeld, 1996). Various models of imitation, ranging from ethological (Jacobson, 1979) and learning theories (Miller and Dollard, 1941) to intermodal matching (Meltzoff, 1988) and the mirror neuron system model (Iacoboni et al, 2001; Wohlschlager and Bekkering, 2002) successfully explained some aspects of neonatal imitation, but failed to explain why babies start to imitate and what the motivation is for their first imitations.

In our studies we found that newborn babies not only imitated gestures but also spontaneously started to initiate them (after several imitation cycles) and were waiting for the experimenter to respond (Nagy and Molnar, 1994, 2004). Consequently, as a laboratory definition for this ‘provocation’ phenomenon in this study we defined it that if a baby produced a previously imitated gesture, 120 or more secs after the experimenter’s similar gesture or after the baby’s own previous imitative response, and the baby was looking at the experimenter, then this behaviour may indicate that the baby initiates the gesture and is waiting for a response. Several long-lasting ‘dialogues’ were initiated by newborn babies this way, i.e. the baby ‘initiated’, the experimenter responded, the baby responded, the experimenter responded, etc. in a precisely timed, very fast, overlapping reciprocal ‘conversation’. These imitations and initiations were accompanied by different psychophysiological patterns; while babies imitated their heart rate increased, while initiated, their heart rate decreased as if they were expecting a response. Imitation and provocation – two naturally otherwise intertwined phenomena – could be a laboratory model of every human communication. These results mean that infants are equipped with a powerful innate reciprocal communicative ability, which originates from imitation (an innate sensitivity to a sympathetic other human being, Trevarthen, 2001, 2003) and this communicative ability presumably evolves later to language.

Imitation is a very effective call for another persons’ attention in young preverbal infants and even in toddlers. Nadel et al (1999) found that 2-year old toddlers can develop long ‘interactions’ with a peer only by using imitation but not in any other control situations. Imitation is not only present right from birth but also goes much beyond in learning; imitation is a motivated behaviour to open and maintain intimate and long interactions much before babies have mastered language.

In summary, initiation and imitation – innate abilities of the human infant - offer a laboratory model for every communication, namely responding and opening, the first turn-taking dialogues. Imitation offers a universal and innate mechanism for complex intersubjective communication not only for the sake of copying, learning, reproducing a movement or achieving the potential goal of the imitated movement, but to get connected to the other person through long-lasting intimate interactions much before language develops.

Our studies also found an interesting laterality in neonatal imitation. In an experiment (Nagy et al, 2003, 2004) where randomly modelled left and right handed index finger extension movements to human neonates in their first 3-96 hours of lives, babies not only imitated the specific finger movement but also showed an interesting left-sided bias in the imitation but not during the baseline period.

These data suggest that human neonates may use a specific lateralized brain system for imitation. Whether this system is the same described by Arbib, and whether this system is identical to the system described in adult monkeys and humans, remain an open question.

Several issues need to be further investigated to examine if a lateralized mirror neuron system in newborns is responsible for imitation. Based on our results, imitative finger movements in newborns may be a useful method to test the laterality of the brain system underlying neonatal imitation (i.e. finger and hand movements can be lateralized while mouth, and tongue movements rarely).

The motor pathways underlying imitative movements also need further exploration in early infancy. The left ipsilateral motor pathway has a stronger influence on fine complex motor movements even in adults (Chen et al, 1997). In young infants, further advantage of the ipsilateral motor pathway is that it is relatively faster than the contralateral (Eyre et al, 2001). In our studies the first finger movement imitations occurred in an average of 25.23 sec (SD=45.93) after the first modelling, and the second imitations 8.21 sec (SD=16.00) after the next modelling, which is much faster than was previously thought (Heimann, 2001) however, the interactive nature of our experiments may partly explain the difference. During overlapping imitative exchanges with the experimenter, reaction times became even shorter. Given the fast reaction times during imitations, the role of the ipsilateral motor pathway cannot be excluded. Therefore, it may be possible that for these relatively fast and precisely timed fine finger movements during imitative exchanges the brain utilizes the faster, and more effective ipsilateral motor pathway which could be a support for the left-sided mirror neuron system for imitation.

However, through contralateral pathways, the early advantage of the right hemisphere (Chiron et al, 1997; Shore, 2000; Trevarthen, 2001) in the first months of life may also affect the lateralized appearance of the first imitative gestures. Motivated behaviours such as emotional facial expressions in humans and in chimpanzees (Sackeim et al, 1978; Fernandez-Carriba et al, 2002) are also stronger on the left side which may be another possible explanation for the first left-handed imitations as motivated expressive behaviours.

Newborns are born with the ability to develop reciprocal communicative exchanges or conversations much before language, and the underlying presumably lateralized neural system may be the lateralized mirror neuron system, although this needs further investigation.

References

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