Adult tactile stimulation during face-to-face interactions modulates five-month-olds' affect and attention.

3 studies were designed to investigate infant responses to tactile stimulation during brief adult-infant interaction using a modified still-face (SF) procedure. When adults pose a neutral SF expression, infants decrease gazing and smiling at the adults, and some increase grimacing, relative to normal interaction periods. This SF effect was substantially reduced in Study 1 when mothers or strangers continued to touch infants during the SF period. In Studies 2 and 3, tactile versus visual and active versus passive aspects of adult touch were isolated during different SF periods. Visible, active adult hands unaccompanied by touch elicited infant attention, but not smiling, during the SF period. By contrast, active, not passive, adult touch substantially reduced the SF effect, even when the adult's hands were invisible. In the latter condition, infants continued to gaze and smile at the adult's SF. Thus, adult facial expressions are not the only modulator of infant affect and attention during social exchanges; adult touch appears to play an active role.