Social Learning and the Acquisition of Snake Fear in Monkeys
Susan Mineka University of Texas at Austin
Michael Cook University of Wisconsin--Madison
The origins and development of predator avoidance have been of long-standing interest to both primatologists and comparative psychologists. Snake avoidance has been of special interest in part because such a wide range of free-ranging monkeys have been observed to exhibit fearful reactions to the appearance of snakes (e.g., Hall & DeVore, 1965, for chacma baboons [Papio ursinus]; Struhsaker , 1967, and Seyfarth, Cheney, & Marler, 1980a, 1980b, for vervet monkeys [Cercopithecus aethiops]; J. Robinson, personal communication, February 1985, for the dusky titi [Callicebus moloch) and capuchins [Cebus]). Behavioral manifestations of this fear of snakes include motor acts such as flight, facial expressions indicative of fear, visual monitoring of the snake, and alarm or distress calls (e.g., Hall & DeVore, 1965; Seyfarth et al., 1980a, 1980b; Struhsaker, 1967).
Some investigators have either suggested or assumed that fear of snakes is innate or spontaneous (e.g., Bertrand, 1969; Hebb, 1946; Masserman & Pechtel, 1953; Morris & Morris, 1965). These terms have generally been used to imply that snake fear does not result from any specific experience, although maturational or general experiential factors may be involved. Other investigators have argued that some form of learning is probably necessary for the development of fear of snakes (e.g., Haselrud, 1938; Schiller, 1952; Wolin, Ordy, & Dillman, 1963; Yerkes & Yerkes, 1936). Yerkes and Yerkes, for example, reached this conclusion based on their finding that adult chimpanzees (Pan troglodytes) exhibited greater snake fear than did infant chimps. Similarly, Seyfarth et al.'s ( 1980b) results