Imitation of tongue protrusion in human neonates: Specificity of the response in a large sample.

Abstract

Although a large body of evidence has accumulated on the young human infant's ability to imitate, the phenomenon has failed to gain unanimous acceptance. Imitation of tongue protrusion, the most tested gesture to date, was examined in a sample of 115 newborns in the first 5 days of life in 3 seating positions. An ethologically based statistical coding system that coded all mouth and tongue movements regardless of whether they were imitative was employed. In order to assess the role of arousal, all arm and finger movements, as well as the infants' states, were coded. Neonates selectively increased the frequency of the strong, but not the weak, tongue protrusions; did not change their states; and did not increase the frequencies of the arm and general finger movements from the baseline to the modeling period, and the position of the baby significantly affected the outcome measures. The results confirm the human neonate's imitative ability, provide evidence that neonatal imitation is not an arousal response, and demonstrate that methodological factors affect the results.