Harold Gouzoules - US grants

In this decade, research has revealed rudimentary but intriguing similarities between certain aspects of human language and the vocal communication of monkeys living in social groups. There are parallels in categorical perception of primate calls and speech, in some of the functions of calls and words, and even in the neural structures involved in the control and production of speech and monkey calls. Several recent studies have suggested that there may be developmental affinities as well. For example, infants and juveniles apparently require experience for both production and proper contextual usage of calls that effectively represent objects or events in their external environments. Complexity in the vocal communication of macaque monkeys is the theme of research by Drs. Harold and Sarah Gouzoules. In previous work on two species of macaques, the Gouzouleses found that acoustically distinct types of recruitment screams are associated with specific features of the situation (e.g., the relative dominance rank of an opponent and the severity of the attack) and appear to provide allies with information pertinent to decisions about intervention tactics. The Gouzouleses now are investigating the acquisition of communicative competence by young macaques and the question of species differences in the acoustic features of calls used in similar contexts. Vocalizations and concomitant behavioral data will be collected on three groups of monkeys (representing three macaque species) maintained in large outdoor enclosures at the Yerkes Regional Primate Research Center of Emory University. The Gouzouleses' novel approach to the analysis of the developmental modification of vocal behavior employs a multivariate statistical technique (discriminant analysis) and a battery of two dozen acoustic measurements to assess differences between adults, juveniles, and infants.

While there is evidence that learning plays a role in the development of the correct usage of certain vocalizations in several species of monkeys and apes, there are few studies that have demonstrated such plasticity in the production of calls. The present research investigates developmental complexity in primate vocal communication. Behavioral data, tape-recordings, and computer-aided spectrography will be used to study the acquisition and significance of pigtail macaque (Macaca nemestrina) vocal "signatures." The project focuses on recruitment screams, vocalizations that have been found to designate events and objects in the animals' external environment and that thus are rudimentarily semantic. Calls used in the recruitment of allies during fights require knowledge of kinship and dominance relationships in the group and are therefore ideal to test hypotheses that learning may be involved in the development of nonhuman primate vocal behavior. These calls have "signature" information in their acoustic structure that may serve to identify kin groups. Foster-reared infants will be studied for evidence that they acquire the signature of their adoptive matriline. The long-term aim of this research on the vocal communication of monkeys is to explore cognitive dimensions of primate behavior that may ultimately provide insights into the evolutionary origins of human language. Results should also contribute to a better understanding of the criteria for appropriate primate models for studies of language acquisition.

sociology /anthropology; psychology; communication behavior; Mammalia; Primates; behavioral /social science research tag;

This project focuses on nonhuman primate vocal communication and its biological and evolutionary relationships to cognition and social behavior. In recent years there has been increased appreciation of the importance of vocal communication in the social lives of nonhuman primates and a goal of the current research is greater understanding of complexity in the vocal signals of monkeys. Studies have indicated signals can represent objects and events in the external world (i.e., have the property of external reference) such findings raise the possibility that animal communication might share the denotative context independence of human language symbols. A complicating issue in efforts to categorize the primate world reflected in communication is that researchers have approached the problem as though the animals classify items with a logic system in which there are only two truth values, 1 or 0 (true and false). Although studies have established associations between differen t vocalizations and referents using this simple dichotomy, it is likely that such bivalent logic is not the actual basis for the categorization of many things communicated about by monkeys. Our research supports this prediction and suggests that a multi-valued or fuzzy logic system, one with more than two truth values, might provide a more realistic way to conceptualize the categorization of certain referents of monkey vocalizations. However, emotional and motivational referents of calls are also indicated in certain vocalizations such as adult copulation calls and the distress cries of infants. As more is learned about how nonhuman primates classify both their physical and social worlds through study of their communication systems, the knowledge gained can be employed in the design of experiments that explore critical cognitive and emotional dimensions of primate behavior relevant to understanding the evolutionary history of our own species. FUNDING Yerkes $20,000 1/01/98 - 12/31/98 PUBLICATIONS Gouzoules, H., Gouzoules, S. and Tomaszycki, M. Agonistic screams and the classification of dominance relationships are monkeys fuzzy logicians? Animal Behaviour 55:51-60, 1998. Gouzoules, H., Gust, D.A., Donaghey, B. and St. Andre, E. Estrus vocalizations in two primate species (Cercocebus torquatus atys and Macaca nemestrina) evidence for an effect of intrasexual competition. Evolution of Communication (In press). Maestripieri, D., Jovanovic, T.J. and Gouzoules, H. Crying and infant abuse in rhesus monkeys. Child Development (In press). P51RR00165-38 1/1/98 - 12/31/98 Yerkes Regional Primate Research Center

The overall goal of this project is to discover better ways to prevent and treat conditions that lead to blinding disorders in human children. We focus on neural and behavioral abnormalities associated with conditions such as congenital cataracts that occur during the neonatal period. During the past year we have continued to study abnormalities in motion processing, oculomotor behavior, and regulation of eye growth that occur following neonatal visual deprivation, but not during visual deprivation initiated somewhat later during postnatal development. These include abnormal growth of the eye leading to anisometropia, and asymmetrical responses to horizontal motion as assessed with visually evoked potentials and oculomotor measures. Monkeys reared under conditions of neonatal visual deprivation in previous years continue to be studied for the long-term presence of all of these disorders. Five new animals were reared under conditions of restricted binocular expo sure duri ng the past year, and those infants will be tested with ophthalmological, electrophysiological, psychophysical, and oculomotor methods during the coming year. FUNDING NIH EY05975 $166,645 7/1/95 - 6/30/00 PUBLICATIONS Boothe, R.G. and Fulton, A.B. Amblyopia. In Principles and Practice of Ophthalmology, 2nd Edition, D.M. Albert and F.A. Jakobiec (Eds.), W.B. Saunders Company, (In press). Bradley, D.V., Fernandes, A., Lynn, M., Tigges, M. and Boothe, R.G. Emmetropization in the rhesus monkey (Macaca mulatta) Birth to young adulthood. Invest. Ophthalmol. Vis. Sci. (In press). Bradley, D.V., Fernandes, A. and Boothe, R.G. The refractive development of untreated eyes of rhesus monkeys varies according to the treatment received by their fellow eyes. Vision Res. (In press). Brown, R.J., Wilson, J.R., Norcia, A.M. and Boothe, R.G. Development of directional motion symmetry in the monocular visually evoked potential of infant monkeys. Vision Res. 38:1253-1263, 1998. Wilson, J.R., Noyd, W.W., Aiyer, A.D., Norcia, A.M., Mustari, M.J. and Boothe, R.G. Asymmetric responses in cortical visually evoked potentials to motion are not derived from eye movements. Invest. Ophthalmol. Vis. Sci. (In press). P51RR00165-38 1/1/98 - 12/31/98 Yerkes Regional Primate Research Center