In 1975, Edward Tronick and colleagues first presented the "still face experiment" to colleagues at the biennial meeting of the Society for Research in Child Development. He described a phenomenon in which an infant, after three minutes of "interaction" with a non-responsive expressionless mother, "rapidly sobers and grows wary. He makes repeated attempts to get the interaction into its usual reciprocal pattern. When these attempts fail, the infant withdraws [and] orients his face and body away from his mother with a withdrawn, hopeless facial expression." It remains one of the most replicated findings in developmental psychology.
Once the phenomenon had been thoroughly tested and replicated, it became a standard method for testing hypotheses about person perception, communication differences as a result of gender or cultural differences, individual differences in attachment style, and the effects of maternal depression on infants. The still-face experiment has also been used to investigate cross-cultural differences, deaf infants, infants with Down syndrome, cocaine-exposed infants, autistic children, and children of parents with various psychopathologies, especially depression.
Why has this experiment, first published in the mid-1970s, become so important?
The still face experiment demonstrated that very young infants already have several basic building blocks of social cognition in place. It suggested that they have some sense of the relationship between facial expression and emotion, that they have some primitive social understanding, and that they are able to regulate their own affect and attention to some extent. The infants' attempts to re-engage with their caregivers also suggest that they are able to plan and execute simple goal-directed behaviors.
In addition, the still face experiment is among the more reliable and valid measurements of infant cognition and behavior; infants find it more disturbing than other violations of normal social interactions (such as the Ainsworth Strange Situation). The response is very complex, with infants displaying subtle facial cues such as dampened smiles, yawns, and sideways glances at the mother. Further, and perhaps most importantly, the still face experiment was the most revealing experiment conducted in terms of infant social cognition. By 1975, researchers had already devised ways to describe and quantify the reciprocal social exchanges that are characteristic of infants and their caregivers. However, the still face experiment allowed researchers to examine the ways in which infants spontaneously initiate social exchanges and the way they modulate their affect and attention, and provides rich data on the ways in which infants re-organize their behavior after the re-establishment of the reciprocal interaction. Importantly, it is a very easy experiment for researchers and parents to properly execute, which is perhaps why it is so popular.
The still face experiment has also proved useful in determining the extent of an infant's social world. That is, the still face effect is not only elicited by the mother (i.e. the primary caregiver), but also by fathers, strangers, and even by televised images of other adults. However, infants do not respond in similar ways to objects, no matter how interesting, interactive, or dynamic they appear to be. This provides more evidence that young infants readily categorize the world into potential social partners and inanimate objects.
The still-face experiment has likewise been useful in answering questions about how the still face effect may be related to earlier experiences and how it may predict later social-emotional variables. For example, variations in the still-face effect have been associated with mothers' baseline sensitivity and interactive style, and the infants' later attachment classification at age 1, internalizing (e.g. depression, anxiety) and externalizing (e.g. aggression, impulsivity) behaviors at 18 months, and behavior problems at age 3.
For an experiment that is so useful, so robust, so popular, one might think that it has outlived its usefulness, at least as far as research is concerned. But despite the robustness of the effect, nobody has been able to fully explain it. No theoretical paradigm has been able to account for the infants' response. Therefore, it is an area open for more investigation.
Adamson, L., & Frick, J. (2003). The Still Face: A History of a Shared Experimental Paradigm Infancy, 4 (4), 451-473 DOI: 10.1207/S15327078IN0404_01
Tronick, E., Adamson, L.B., Als, H., & Brazelton, T.B. (1975, April). Infant emotions in normal and pertubated interactions. Paper presented at the biennial meeting of the Society for Research in Child Development, Denver, CO.