Abstract : Infants between 12
and 21 days of age can imitate both facial and
manual gestures; this behavior cannot be
explained in terms of either conditioning or
innate releasing mechanisms. Such imitation
implies that human neonales can equate their own
unseen behaviors with gestures they see others
perforin.
Piaget and other students of developmental
psychology consider the imitation of facial
gestures to be a landmark achievement in infant
development. Infants are thought to pass this
milestone at approximately 8 to 12 months of
age. Infants younger than this have been
postulated to lack the perceptual-cognitive
sophistication necessary to, match a gesture
they see with a gesture of their own which they
cannot see. The experiments we report show that
the infant's imitative competence has been
underestimated. We find that 12- to 21-day-old
infants can imitate both facial and manual
gestures (Fig). This result has implications for
our conception of innate human abilities and for
theories of social and cognitive
development.
An experimental evaluation of the neonate's
imitative competence raises several
methodological difficulties. One consists of
distinguishing true imitation from a global
arousal response. For example, one can conclude
nothing about imitation if an infant produces
more tongue protrusions in response to a tongue
protrusion demonstration than he does to the
presentation of a neutral facial expression. It
would be more parsimonious simply to conclude
that a moving, human face is arousing for the
infant and that increased oral activity is part
of the infant's arousal response. A second issue
involves , controlling interactions between
aduit and infant that might shape the imitative
response. We found that if parents were informed
of the imitative tasks we planned to examine,
they practiced these gestures with their infants
before coming into the laboratory so that their
baby "would do well on the test." In reviewing
films of preliminary work, we also noticed that
the examiner tended to alter the rhythm of his
tongue protrusion as a function of the response
of the infant. These kinds of interactions would
expose findings of imitation to a variety of
explanations, including the possibility that the
infants were merely being conditioned to imitate
tongue protrusion. A third issue concerns the
scoring of the infant's responses. The movements
tested were, not generally produced in a
discrete, unambiguous fashion and not
surprisingly, there were'gross differences in
the scoring as a function of whether or not the
observer knew which gesture had been
demonstrated to the infant.
In the experiments we now report, these three
issues are addressed as follows. Each infant's
response to one gesture is compared to his
response to another similar gesture demonstrated
by the same adult, at the same distance from the
infant, and at the same rate of movement. For
instance, we test whether infants produce more
tongue protrusions after an adult demonstrates
tongue protrusion than after the same adult
demonstrates mouth opening, and vice versa. If
differential imitation occurs, it cannot be
attributed to a mere arousal of oral activity by
a dynamic, human face. Parents were not told
that we were examining imitation until after the
studies were completed; moreover, the
experiments were designed to preclude the
possibility that the experimenter might alter
the rhythm of his demonstration as a function of
the infant's response. The infant's reactions
were videotaped and then scored by observers who
were uninformed of the gesture shown to the
infant they were scoring. [...]
At least three different mechanisms could
potentially underlie the imitation we
report.
1) It could be argued that the imitation is
based on reinforcement administered by either
the experimenter or the parents. In order to
prevent the experimenter from shaping the
infant's imitative responding, the procedure
directed that he maintain an unreactive, neutral
face during the response period. The
experimenter's face was videotaped throughout
both experiments in order to evaluate whether
this procedure was followed. The videotaped
segments were shown to observers whose task it
was to score any reinforcements that the
experimenter administered. No smiles or
vocalizations were noted in any trial. Indeed,
the only changes from the passive face occurred
in three trials in experiment 1, when the
experimenter was judged to "blink extremely
rapidly." Considering only experiment 2, then,
the experimental procedure does not appear to
have been violated, and therefore, differential
shaping of the mouth-opening and
tongue-protrusion responses during the
successive 150-second response periods is an
unlikely source of the effects obtained. Since
none of the parents were informed about the
nature of the study, special practice on
imitative tasks at home in preparation for the
experiment was avoided. Further, informal
questioning revealed that no parent was aware of
ever having seen babies imitating in the first
21 days of life; indeed, most were astonished at
the idea. Thus, a history of parental
reinforcement seems an improbable basis for
imitation at this very early age.
2) This early imitation might be based on an
innate releasing mechanism such as that
described by Lorenz and Tinbergen (6). This view
would hold that tongue protrusion, mouth
opening, lip protrusion, and sequential finger
movement are each fixed-action patterns and that
each is released by the corresponding adult
gesture (sign stimulus). The overall
organization of the infant's imitative response,
particularly its lack of stereotypy, does not
favor this interpretation. In addition, the fact
that infants imitate not one, but four different
gestures, renders this approach unwieldy.
3) The hypothesis we favor is that this
imitation is based on the neonate's capacity to
represent visually and proprioceptively
perceived information in a form common to both
modalities. The infant could thus compare the
sensory information from his own unseen motor
behavior to a "supramodal" representation of the
visually perceived gesture and construct the
match required. In brief, we hypothesize that
the imitative responses observed are not
innately organized and "released," but are
accomplished through an active matching process
and mediated by an abstract representational
system. Our recent observations of facial
imitation in six newborns-one only 60 minutes
old-suggest to us that the ability to use
intermodal equivalences is an innate ability of
humans. If this is so, we must revise our
current conceptions of infancy; which hold that
such a capacity is the product of many months of
postnatal development. The ability to act on the
basis of an abstract representation of a
perceptually absent stimulus becomes the
starting point for psychological development in
infancy and not its culmination.
