Across all languages studied to date, audiovisual speech exhibits a consistent rhythmic structure. This rhythm is critical to speech perception. Some have suggested that the speech rhythm evolved "de novo" in humans. An alternative account--the one we explored here--is that the rhythm of speech evolved through the modification of rhythmic facial…

In this review, we place equal emphasis on production, usage, and comprehension because these components of communication may exhibit different developmental trajectories and be affected by different neural mechanisms. In the animal kingdom generally, learned, flexible vocal production is rare, appearing in only a few orders of birds and few…

The mirror system provided a natural platform for the subsequent evolution of language. In nonhuman primates, the system provides for the understanding of biological action, and possibly for imitation, both prerequisites for language. I argue that language evolved from manual gestures, initially as a system of pantomime, but with gestures…

Although apes understand others' goals and perceptions, little is known about their understanding of others' emotional expressions. We conducted three studies following the general paradigm of Repacholi and colleagues (1997, 1998). In Study 1, a human reacted emotionally to the hidden contents of two boxes, after which the ape was allowed to…

Research on the relationship between the representation of space and time has produced two contrasting proposals. ATOM posits that space and time are represented via a common magnitude system, suggesting a symmetrical relationship between space and time. According to metaphor theory, however, representations of time depend on representations of…

Previous neuroimaging research has attempted to demonstrate a preferential involvement of the human mirror neuron system (MNS) in the comprehension of effector-related action word (verb) meanings. These studies have assumed that Broca's area (or Brodmann's area 44) is the homologue of a monkey premotor area (F5) containing mouth and hand mirror…

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…

Previous studies have demonstrated the sensitivity of chimpanzees to facial configurations. Three studies further these findings by showing this sensitivity to be specific to second-order relational properties. In humans, this type of configural processing requires prolonged experience and enables subordinate-level discriminations of many…

Primates, including humans, communicate using facial expressions, vocalizations and often a combination of the two modalities. For humans, such bimodal integration is best exemplified by speech-reading--humans readily use facial cues to enhance speech comprehension, particularly in noisy environments. Studies of the eye movement patterns of human…

This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys ("Macaca mulatta"). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in…

Behavioral and electrophysiological evidence suggests a gradual, experience-dependent specialization of cortical face processing systems that takes place largely in the 1st year of life. To further investigate these findings, event-related potentials (ERPs) were collected from typically developing 9-month-old infants presented with pictures of…

A comparative developmental framework was used to determine whether mutual gaze is unique to humans and, if not, whether common mechanisms support the development of mutual gaze in chimpanzees and humans. Mother-infant chimpanzees engaged in approximately 17 instances of mutual gaze per hour. Mutual gaze occurred in positive, nonagonistic…

Linguistics retains from its antecedents, philology and the study of sacred writings, some of their apologetic and theological bias. Thus it has not been able to face squarely the question how linguistic function may have evolved from animal communication. Chimpanzees' use of signs from American Sign Language forces re-examination of language…

The debate over whether primates can be taught visual language is examined, and evidence of use of nonverbal language in primate studies is compared with the language criteria of a number of linguistic researchers. Background information on language, visual language (including sign language), and the parameters of the studies is offered, including…

A collection of research materials on sign language and primatology is presented here. The essays attempt to show that: sign language is a legitimate language that can be learned not only by humans but by nonhuman primates as well, and nonhuman primates have the capability to acquire a human language using a different mode. The following…