During the earliest weeks of life, the corners of a baby's mouth often curl up in a facial
expression that looks for all the world like a smile. Most experienced mothers do not pay
much attention to these smiles, however, because they are most likely to come when the
infant is asleep or very drowsy. Emde and his colleagues studied the nature and origin of
infants' smiles by recording their brain waves at times when they were and were not
smiling and the nature of the social feedback the infants received when they smiled.
The researchers found that in the days after birth the babies' smiles came primarily
during rapid-eye-movement (REM) sleep and were accompanied by bursts of brain-wave
activity originating in the brain stem. Emde and Jean Robinson (1979) call these
endogenous smiles REM smiles. During the second week, smiles began to appear when the
infants were awake, but they did not correlate with any particular events in the
environment. Emde and his colleagues found that even when the infants were awake
their smiles were accompanied by the pattern of brain waves characteristic of drowsiness
and REM sleep.
Emde and his colleagues reported that the frequency of REM smiles decreased rapidly
during the next several weeks. In their place there appeared an exogenous smile, one
that responds to stimulation from the environment. Between the ages of 1 month and 2
« months, infants smile indiscriminately at things or people they see, touch, or hear.
Thus this earliest form of exogenous smiling is not really social, even though it is
stimulated from the outside.
To become truly social, babies' smiles must be reciprocally related to the smiles of others;
that is, the babies must both smile in response to the smiles of others and elicit others'
smiles. This is precisely what begins to happen for the first time at the age of 2 « to 3
months as part of the first postnatal bio-social-behavioral shift. This new behavior
depends on the changes in the brain and the nervous system that result in marked
increases in infants' visual acuity and in their ability to scan objects systematically. The
improved visual capacity permits babies to focus their eyes, and thus their smiles, on
people, so that early exogenous smiling can become truly social smiling.
The changes in infants' behavior that accompany the social smile are not lost on their
parents. Quite the opposite; parents report a new emotional quality in their relationship
with their child. The following remarks by two mothers concerning their feelings for
their babies before and after the shift clearly illustrate the social and emotional
implications of the new kind of smiling:
BEFORE THE SHIFT
I don't think there is interaction . . . . They are like in a little cage surrounded by glass and
you are acting all around them but there is no real interaction . . . . I realized I was doing
things for him he couldn't do for himself but I always felt that anyone else could do them
and he wouldn't know the difference. (Robson & Moss, 1970:979--980)
AFTER THE SHIFT
His eyes locked on to hers, and together they held motionless . . . . This silent and almost
motionless instant continued to hang until the mother suddenly shattered it by saying
""Hey!'' and simultaneously opening her eyes wider, raising her eyebrows further, and
throwing her head up and toward the infant. Almost simultaneously the baby's eyes
widened. His head tilted up . . . , his smile broadened . . . . Now she said, ""Well hello! . . .
heello, . . . heeelloooo!,'' so that her pitch rose and the ""hellos'' became longer and more
stressed on each successive repetition. With each phrase the baby expressed more
pleasure, and his body resonated almost like a balloon being pumped up. (Stern, 1977:3)
Contrasting the "before" and "after" interactions we see that the older child displays a
new emotion, joy--expressed in his smile and his whole body--to help account for the
mother's sense of a new, and more connected, relationship.
The Social Smile and Social Feedback
The importance of social feedback to the achievement of bio-social-behavioral shifts is
dramatically demonstrated by research conducted by Selma Fraiberg (1974) on the
development of congenitally blind infants. Like sighted infants, blind babies exhibit REM
smiles. But unlike sighted infants, they may not exhibit the same shift to social smiling at
2 « months.
Under normal conditions of growth, the social smile is connected to visual exploration of
the world. It depends on increased visual capacity and on visual feedback from people
who smile back. Blind infants cannot explore the world visually and hence may not
establish the feedback loop they need in order to develop social smiling.
The frequent failure of blind infants to make the expected shift toward social smiling also
means that their sighted parents cannot use their baby's facial expressions as a gauge by
which to evaluate their own efforts to help their infant. But it does not mean that blind
infants receive no social feedback or that they cannot acquire social smiling. After all,
their brains are maturing like those of sighted children. The problem is that they cannot
express their increased capacities in visually related ways. In the absence of this major
channel for social feedback, parents must find alternate ways to interact with their blind
children.
The intuitive solution that some parents of blind children work out is to establish
communication through touch. Fraiberg noticed that many of these parents bounce,
nudge, and tickle their children far more than the parents of sighted children. At first all
this manipulation struck Fraiberg as socially abnormal, but then she noticed that the
touching made the children smile and realized that tactile stimulation was a good
substitute for the smiling face that elicits the smiles of sighted babies. Through touch the
parents had found a way to get the feedback that they needed from their infants--and to
provide feedback that the infants needed from them. Fraiberg used this observation to
design a training program to help blind infants and their parents (Fraiberg, 1974). Parents
were taught to attend carefully to the way their children used their hands to signal their
intentions and reactions and how to organize their baby's environment to encourage
interaction. Once the children of these parents were provided with appropriate
feedback, they began to develop social smiling.
The success of Fraiberg's training program indicates that social smiling does not arise
simply from the fact that an infant's brain has matured to the point where social smiling
is possible. For social smiling to emerge, appropriate interaction with others is necessary;
when this new behavior does emerge, a new affective quality is able to develop between
infants and their parents. As we will see in other periods of a child's life, development
results from a complex interaction of biological, social, and behavioral changes. The
notion of bio-social-behavioral shifts helps us to keep this important principle in mind.