The issue examined was whether infants require sight of their hand when first beginning to reach for, contact, and grasp objects. 7 infants were repeatedly tested between 6 and 25 weeks of age. Each session consisted of 8 trials of objects presented in the light and 8 trials of glowing or sounding objects in complete darkness. Infants first contacted the object in both conditions at comparable ages (mean age for light, 12.3 weeks, and for dark, 11.9 weeks). Infants first grasped the object in the light at 16.0 weeks and in the dark at 14.7 weeks, a nonsignificant difference. Once contact was observed, infants continued to touch and grasp the objects in both light and dark throughout all sessions. Because infants could not see their hand or arm in the dark, their early success in contacting the glowing and sounding objects indicates that proprioceptive cues, not sight of the limb, guided their early reaching. Reaching in the light developed in parallel with reaching in the dark, suggesting that visual guidance of the hand is not necessary to achieve object contact either at the onset of successful reaching or in the succeeding weeks.

Research during ihe past 10 years on the neonatal head-turn response to off-centred rattle sounds is reviewed, and various procedural and stimulus conditions that influence the probability of eliciting a correct response arc identified. Also, the existence of a U-shaped developmental function is confirmed in a crosssectional study of 104 infants between 3 days and 7 months of age. Nconates responded reliably, but slowly; the response decreased in frequency and magnitude between 1-3 months of age and increased again by 4-5 months of age. Speculation that this U-shaped function reflects a maturational shift in locus of control from subcortical to cortical structures was supported by the infants' responses to the precedence effect (PE), which is thought to be corticalJy mediated. The PE was produced by playing the rattle sound through two loudspeakers with the output of one delayed by 5 ms, relative to the other; adults perceive only one sound at the leading loudspeaker. As predicted, nconates failed to respond to the PE, and the onset of correct PE responses corresponded closely to the upswing in the U-shaped function for SS responses. Other explanations for the temporary decline in orientation responses to sound are also discussed. KKSUME Nous avons passe en revue les rechcrches depuis 10 ans sur le mouvement de la tele en rcponsc a des sons de hochet decentres et nous avons identific des procedures variees et des conditions de stimulus qui influencent la probability de dcclcncher une reponsc correcte. Nous avons aussi confirmc l'cxistence d'une function dcvcloppemenlale en forme de U dans unc etude cross-section impliquant 104 enfants ages de 3 jours a 7 mois. Les nouveaux-ncs rcpondaient surcment mais lentement; la rcponsc diminuail en frequence et en magnitude cntre 1 et 3 mois et augmentait encore a partir de 5 mois. L'idee que ccttc fonction en forme dc U rcllete un displacement du lieu dc controle, lors du proccssus de maturation, des structures sous-corticales aux structures corticales, etait appuyee par les reponscs des enfants a l'effei de precedence (PE) dom le controle seraii cortical. Le PR ctait produit par le son du hochet dans deux haut-parleurs dont remission de l'un etait diffcrcc de 5 ms rclativement a l'autrc; les adultes percoivent seulement le premier son 6mis ct non le second. Tel que preVu, les nouvcaux-nes ne repondaicnt pas au PE et Tarrivcc des reponses PE corrcctcs correspondait dc prcs avec la branche asccndante de la fonction en forme de U pour les reponses SS. D'autres explications pour le declin temporaire des reponses d'orientation au son sont aussi discutccs.

The issue examined was whether infants require sight of their hand when first beginning to reach for, contact, and grasp objects. 7 infants were repeatedly tested between 6 and 25 weeks of age. Each session consisted of 8 trials of objects presented in the light and 8 trials of glowing or sounding objects in complete darkness. Infants first contacted the object in both conditions at comparable ages (mean age for light, 12.3 weeks, and for dark, 11.9 weeks). Infants first grasped the object in the light at 16.0 weeks and in the dark at 14.7 weeks, a nonsignificant difference. Once contact was observed, infants continued to touch and grasp the objects in both light and dark throughout all sessions. Because infants could not see their hand or arm in the dark, their early success in contacting the glowing and sounding objects indicates that proprioceptive cues, not sight of the limb, guided their early reaching. Reaching in the light developed in parallel with reaching in the dark, suggesting that visual guidance of the hand is not necessary to achieve object contact either at the onset of successful reaching or in the succeeding weeks.

We measured head circumference and interaural distance in infants between birth and 22 weeks of age. A small sample of preschool children and adults were measured for comparison over the life span. We used these data to calculate changing interaural time differences across ages. Large shifts in this important binaural cue suggest that an ongoing developmental process recalibrates the association between interaural time differences and spatial location. These new data confirmed the sex differences in head circumference described in the Berkeley Growth Study (Eichorn & Bailey, 1962) and found no secular trend in this measure in the 60 years since the earlier data were collected.Growth of the head during gestation and early infancy is a significant index of normal development. Head circumference at birth reflects prenatal brain growth (Dekaban, 1970;Winick & Rosso, 1969), and postnatal patterns of growth have been related to neurological functioning and cognitive performance (Eckerman, Sturm, & Gross, 1985). Measurements of growth in head circumference from birth through adulthood have been obtained on several longitudinal samples. One of the best known is the Berkeley Growth Study (Eichorn & Bayley, 1962) in which measurements of head circumference were obtained at monthly intervals from birth through 1 year of age and at longer intervals thereafter to young adulthood. Head circumference increased an average of 21.8 cm between birth and 25 years of age, a 62% increase over birth measurements.Increasing head size, especially during infancy when growth is most rapid, carries implications for perceptual functioning. Aslin, Pisoni, & Jusczyk (1983) suggested that infants* smaller heads may bias their sound localization toward higher frequencies and reduce the effectiveness of time cues, because the magnitude of interaural differences would be less. In terms of the

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