“…In addition to the repetitive and exaggerated affiliative vocalizations of infant-directed speech (the high pitch, soft volume, inviting pauses, and gentle undulations of which are nonthreatening and nonassertive), 3 mothers use exaggerated affiliative facial expressions of Look At, Eyebrow Flash, Raise Eyebrows, Head Bob, Smile, and Nod (Schelde and Hertz 1994;Grant 1968Grant , 1972 and Mutual Gaze, and rhythmically repeated affiliative gestures (Touch, Stroke, Pat, Hold hand, Groom, Hug, and Kiss). Such gestures, and some of the facial expressions, are also conspicuous in affiliative contexts in other primates, particularly in chimpanzees and bonobos (deWaal 1997).…”