Neighbor effect: evidence of affiliative and agonistic social contagion in captive chimpanzees (Pan troglodytes)

• Published in: American journal of primatology Vol. 66; no. 2; pp. 131 - 144
• Main Authors: Videan, Elaine N., Fritz, Jo, Schwandt, Melanie, Howell, Sue
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-06-2005; Wiley-Liss
• Subjects: Agonistic Behavior - physiology; Animal ethology; Animals; Animals, Laboratory; behavior; Biological and medical sciences; Biological anthropology; chimpanzee; Chimpanzees; Cooperative Behavior; Fundamental and applied biological sciences. Psychology; Imitative Behavior - physiology; Mammalia; neighbor effect; Pan troglodytes; Pan troglodytes - physiology; Primate behaviour; Primates; Primatology; Psychology. Psychoanalysis. Psychiatry; Social Behavior; social contagion; Statistics, Nonparametric; Vertebrata; vocalization; Vocalization, Animal - physiology; Acoustic communication; Animal communication; Intraspecific relation; Sound production; vocalization; Pan troglodytes; Vertebrata; Mammalia; Social interaction; Primates; Simioidea; social contagion; Captivity; chimpanzee; neighbor effect; behavior; Agonistic behavior
• ISSN: 0275-2565; 1098-2345
• DOI: 10.1002/ajp.20133

Previous studies of captive chimpanzees have demonstrated the “neighbor effect,” or social contagion, with respect to agonistic vocalizations and behaviors. The present study considers whether there is a relationship between behavior patterns in focal animals and the auditory signals of neighboring social groups. Using focal‐group sampling, we collected 172.5 hr of data on 51 subjects (25 females and 26 males) housed in 10 social groups. We performed two‐tailed Wilcoxon matched‐pairs signed‐rank tests to determine whether the relative frequency of the vocalizations (high vs. low) affected the behaviors. In keeping with past research, we found that agonistic noises and vocalizations from neighboring social groups had a significant effect on the rates of focal‐group bluff displays, pant‐hoots, and aggression (P<0.05). In addition, we also found significant relationships between grooming behavior and vocalizations in focal groups, and grooming vocalizations from neighboring groups (P<0.05). The results suggest that social contagion is not limited to aggressive behaviors, but also occurs for affiliative behavior patterns. Am. J. Primatol. 66:131–144, 2005. © 2005 Wiley‐Liss, Inc.