Six-month-olds reliably discriminate different monkey and human faces whereas 9-month-olds only discriminate different human faces. It is often falsely assumed that perceptual narrowing reflects a permanent change in perceptual abilities. In 3 experiments, ninety-six 12-month-olds' discrimination of unfamiliar monkey faces was examined. Following…

Human neonates prefer listening to speech compared to many nonspeech sounds, suggesting that humans are born with a bias for speech. However, neonates' preference may derive from properties of speech that are not unique but instead are shared with the vocalizations of other species. To test this, thirty neonates and sixteen 3-month-olds were…

G. Gergely, H. Bekkering, and I. Kiraly (2002) showed that 14-month-old infants imitate rationally, copying an adult's unusual action more often when it was freely chosen than when it was forced by some constraint. This suggests that infants understand others' intentions as rational choices of action plans. It is important to test whether apes…

This article presents a tentatively "balanced" view (i.e., midway between lean and rich interpretations) of pointing behavior in infants and apes, based upon the notion of intentional reading of behavior without simultaneous attribution of unobservable mental states. This can account for the complexity of infant pointing without attributing…

The effects of appetitive controllability on behavioral and cortisol reactivity to novelty in 12 infant rhesus monkeys were studied. Surrogate-peer-reared infants had homecage access to food treats contingently via lever pressing ("master") or noncontingently ("yoked") for 12 weeks from postnatal month 2. Masters lever-pressed more, but did not…