American Journal of Primatology 44:227–230 (1998) © 1998 Wiley-Liss, Inc. HISTORICAL NOTE Arthur S. Kling: Pioneer of the Primate Social Brain H. DIETER STEKLIS* Department of Anthropology, Rutgers University, New Brunswick, New Jersey Key words: Kling; primate brain; social behavior; brain lesions March 1997 marked the passing of Arthur S. Kling, M.D., bringing to a close an influential chapter in the study of the primate brain and behavior. Over the course of his long, distinguished career, Art Kling contributed to numerous disci- plines and professions, including anthropology, ethology, primatology, psychol- ogy, psychiatry, and the neurosciences. Most will likely remember him for his formidable neuroscience research contributions, and that would be just. Begin- ning in the early 1950s, Kling set out to discover the behavioral functions of a then still mysterious almond-shaped set of nuclei buried deep in the mammalian temporal lobe—the amygdaloid nucleus. So widely celebrated were his attacks on this pivotal limbic system component and the results they yielded that among the amygdala cognoscenti Kling’s name soon became synonymous with the al- mond-shaped structure itself! Perhaps less obvious, though no less celebratory, are Kling’s contributions to primatology and related disciplines. In the mid to late 1960s, primatologists be- gan to busy themselves with finding adaptive–functional explanations for pri- mate sociality itself as well as the remarkable, evident diversity of primate social structures. With few exceptions, research on the physiological or neural mecha- nisms of behavior had concentrated on the learning or cognitive abilities of sin- gly caged macaque (mostly rhesus) monkeys, leaving the behavioral adaptationists in search of the requisite evolved proximate mechanisms of primate sociality. Through a groundbreaking series of experiments, Kling and colleagues pointed the adaptationists toward the mechanisms they were in search of: a set of struc- tures in the primate brain (i.e., neural modules) that underlie social–affiliative behaviors [Kling & Steklis, 1976]. Unquestionably the most dramatic and pio- neering demonstration of the critical importance of this neural substrate for so- cial affiliation was his study of amygdalectomy in wild vervet monkeys [Kling et al., 1970]. For this study, Kling had to find a field primatologist willing to let him amygdalectomize several of their wild social group members. He found a willing colleague in Jane Lancaster, a young anthropologist–primatologist who had been trained by Berkeley’s Sherwood Washburn and was conducting a social behavior study on wild groups of vervet monkeys in Zambia. Following bilateral amygdalectomy, performed on Lancaster’s kitchen table, the operated subjects became social isolates. None of them rejoined their social groups despite friendly *Correspondence to: H. Dieter Steklis, Dept. of Anthropology, Rutgers University, P.O. Box 270, New Brunswick, NJ 08903-0270. Received for publication 4 December 1997; accepted 7 December 1997.