Question

What is the name of the experimental task in which an infant interacts with an adult who first engages in normal social interaction and then suddenly becomes unresponsive?

Answer 1

The still-face interaction paradigm

An experimental task was introduced in 1978 to prove that infants actively contribute to social interaction. It is called the Still-Face Paradigm or SFP.

In the experiment,  3 phases of face-to-face interaction of infants with an adult were tested:  the normal interaction, the still-face (where the adult becomes unresponsive and maintains a neutral facial expression), and a reunion where the adult resumes normal interaction.

Indeed, the still-face paradigm showed effects like increased gaze aversion and less smiling.