Gaze following at 12 and 14 months: Do the eyes matter?

Two questions were addressed: (1) Is the gaze following of infants under 18 months sensitive to eye status? (2) Do they construe looking as referential behaviour? Corkum and Moore (1995) concluded that, prior to 18 months, gaze following is responsive to the head turn alone (H), because infants followed such turns as frequently as conjoint head and eye turns (H/E). Since their results may have been compromised by an absence of targets and a relatively lengthy response time, we retested a 12- and 14-month group with H/E, H and eyes closed (H/Ecl) cues in the presence of targets and with reduced response time. To examine comprehension of referentiality, two more H/E cues were shown-(I) saying 'oh wow' while turning and (2) actively scanning the targets-each intended to increase gaze following if infants regard looking as seeing something. Fourteen-month-olds, but not 12-month-olds, responded significantly more to the standard H/E cue than to the H and H/Ecl cues, indicating the importance of eyes for gaze following at this age. Neither age group, however, responded more to the two 'enhanced' H/E cues than to the standard. In a second experiment, a new 14-month group was tested without targets, and again, responding was significantly greater to H/E than to H and H/Ecl. It was concluded that by 14 months, the eyes are co-equal with the head in controlling gaze following, but whether such head/eye turns are understood as object-directed is problematic.