AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 87227-229 (1992)
Notes and Comments The Origins of Caregiving Behavior
Joan B. Silk Department of Anthropology, University of California, Los Angeles, California 90024
I endorse Dettwyler’s (1991) recent critique of claims that the survival of individuals with significant physical impairments is evidence of compassion and moral decency in prehistoric peoples. My goal here is to extend her critique by incorporating evidence about caregiving behavior drawn from the primatological literature. The three main findings that have generated these claims are (1)Shanidar I: an adult male Neandertal who had sustained multiple fractures, suffered a degenerative joint disease, and was probably paralyzed in one arm and blind in one eye, (2) Romito 2: an adolescent Upper Paleolithic male with acromesomelic dysplasia, a condition clinically characterized by severe growth deficiency, dwarfism, bowing of the forearms, and limited extension of the elbows, (3) Windover boy: a teen-ager with spina bifida who lived approximately 7,500 B.P. The survival of these individuals is often said to provide indirect evidence of the compassion of their caretakers, because these individuals would have been hard-pressed to meet their own subsistence needs. Dettwyler identifies five assumptions that implicitly underlie this conclusion, and provides convincing arguments that none of these assumptions are logically compelling or consistent with the ethnographic evidence. She concludes that the fossil record provides no direct, unambiguous evidence of either caregiving or compassion. Here, I extend Dettwyler’s list to include another problematic assumption. While Dettwyler draws upon the ethnographic record to refute the five assumptions she enumerates, I draw upon evidence from the primatological literature to question a sixth assumption i.e., that care for the disabled is unique to Homo sapiens. In his essay in Natural History, Gould (1988)argues that the survival ofthe Romito dwarf:
@ 1992 WILEY-LISS, INC.
offers our oldest evidence for the nurturing and protection-presumably at some expense to the group-of a handicapped individual who was profoundly different from his peers and physically disadvantaged from birth. All other examples of lifelong physical handicaps at this scale date from the origin of agriculture and complex societies (1988:
18).
However, there is reason to believe that the evolutionary origins of such care may lie much further back in time than the Upper Paleolithic. The primatological literature contains a number of detailed accounts of physically impaired individuals who receive substantial amounts of care from other members of their groups. Several of these cases are described below. In the Arashiyama West group of Japanese macaques, an infant was born with gross locomotor deficiencies. Fedigan and Fedigan (1977) provide the following description of his disabilities: Wania 6672 frequently bumped into objects in his environment, such as bushes, cactus, and other monkeys. His movements were spastic, ataxic, and accompanied by continual head dipping. He grasped food clumsily between his thumb and the rest of his hand, showing little manual dexterity , , , when the least bit excited or hurried, as he often was when trying to catch up with his mother, he spun lurched, and fell continually, his hind limbs being especially still and out of control (1977:207).
They also surmised that Wania 6672 was visually impaired, and unable to recognize individuals farther than 10 feet away. The infant’s behavior was substantially different than that of a healthy infant of the same age and maternal rank: he spent more time resting, giving lost infant calls, nursing and seeking comfort, and following his mother, Wania 66. Wania 6672 spent considerably more time in contact with his mother than the healthy infant, and considerably less time playing. Wania 66 allowed her infant to share her feeding site, sometimes allowing him to eat directly from her hand or lap. She also retrieved him more often than other mothers retrieved their infants, and carried him ventrally for 13 months, much longer than other mothers carry their infants in the ventral position. Wania 6672 disappeared
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from the group at about 13months of age; the precise cause of his death is not known. Fedigan and Fedigan conclude that Wania 6672’s survival was “completely due to his mother’s close attention and support. . . Wania not only gave her first-born infant competent care, she gave him extra care” ( 1977:210). It is also notable that other group members seemed to have provided unusual levels of care for Wania 6672. While infants are occasionally retrieved and carried by individuals other than their mothers, Wania 6672 was retrieved by others at considerably higher rates than other infants. Moreover, he was often retrieved by peers who attempted to comfort him by embracing, huddling, grooming, or playing with him. Fedigan and Fedigan note “it was always extraordinary to see such a young monkey leave its companions to hurry over and cradle an infant hardly smaller than itself” (1977:213). In the early 1970s, Berkson (1973, 1977) conducted a series of experimental studies on the effects of visual impairment on the development of young monkeys. For these studies, permanent visual impairment was experimentally produced by making an incision on the pupil which then scarred and produced a cataract. In one study, four infants from a semi-free ranging group on macaques at La Parguera Island were blinded by this procedure. (The experimental protocol, by itself, must make us question the taxonomic bounds for compassion.) For several years, the behavioral development of these infants was monitored and compared to that of normal infants of the same ages. All of the blind infants survived until the age of three years, when the project was terminated. During the first year, blind infants stayed closer to their mothers and were protected by their mothers more often than were normal infants. During the breeding seasons, mothers of both blind and sighted infants often moved out of proximity to their infants. However, “the blind infants were never left alone, and specific members of the group tended to stay near them and carry them if the group moved (Berkson, 1977: 194). Mothers of two blind infants produced infants during the next birth season. These mothers sometimes carried both their yearlings and newborns at the same time, an unusual behavior for female macaques. Among the chimpanzees at Gombe, Goodall (1986) has documented solicitude of sev-
eral individuals who were paralyzed by polio. The first known victim of the polio epidemic was a month-old infant who lost the use of his arms and legs. His mother supported him carefully, cradled him when he became distressed, and carefully protected his limbs. Although his mother continued to care for him, the infant died shortly after contracting the disease. An adult male, Mr. McGregor, lost the use of both legs in the epidemic. While some adult males displayed at him, and some even attacked him, Humphrey, who was believed to have been his brother, behaved solicitously toward him throughout his ordeal. He once charged and attacked a much higher ranking male who had attacked Mr. McGregor. For several days, Humphrey stayed near Mr. McGregor, leaving only long enough to feed. Years later, an old female, who had been partially paralyzed with polio during the epidemic, followed her daughters to a feeding site. When she arrived, she seemed too tired or weak to climb into the vines to feed. Her daughter approached, presented her mother with a piece of fruit, and sat nearby as she fed. Care for motherless infants and young juveniles may also be relevant to the origins of caregiving behavior. Although motherless individuals are not physically disabled, they are not likely to survive if they do not receive some attention from others. Interactions with motherless infants and juveniles range from passive tolerance, to suckling, active support, and protection (reviewedby Thierry and Anderson; 1986). In general, unweaned infants receive care from adult females, and are likely to survive only if their caretaker is lactating. Weaned infants and juveniles are often cared for by older juveniles and adult males (Thierry and Anderson, 1986). Goodall (1986) has observed several cases in which a chimpanzee provided care to an infant or juvenile who was known or suspected to be its sibling. In one case, a fiveyear-old female chimpanzee named Skosha was cared for by Pallas, her mother’s closest companion, after her mother died. When Pallas died, Skosha cared for Pallas’ fiveyear-old daughter, Kristal. Skosha cared for her until Kristal died one year later. These examples are meant to demonstrate that the capacity to provide care for temporarily or permanently disabled individuals is present among nonhuman primates. I do not mean to imply that caregiving is a particularly common form of behavior among monkeys and apes, as reports of such behavior in
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NOTES AND COMMENTS
the literature are relatively scarce (Cheney and Seyfarth, 1990). The primate literature gives us reason to believe that caregiving behavior antedates the origins of the hominid lineage, but the origins of compassion are considerably harder to date. If “compassion demands some understanding of another’s needs and purposes” (Cheney and Seyfarth, 1990: 2361, then it is problematic to conclude that caregivers are compassionate from their behavior alone. To demonstrate the existence of compassion in monkeys and apes we must demonstrate that they can recognize the physical and emotional needs of other individuals. At present there is no incontrovertible evidence of their ability to do so. In sum, we must have serious reservations about the claim that caregiving is unique t o Homo sapiens. At the same time, we must be cautious about coupling caregiving with compassion among nonhuman primates (or fossil hominids).
LITERATURE CITED Berkson G (1973) Social responses to abnormal monkey infants. Am. J. Phys. Anthropol. 38:583-586. Berkson G (1977) The social ecology of defects in primates. In S Chevalier-Skolnikoff and FE Poirier (eds.): Primate Biosocial Development: Biological, Social, and Ecological Determinants. New York: Garland, pp. 189-204. Cheney DL and Seyfarth RM (1990) How Monkeys See the World. Chicago: Chicago University Press. Dettwyler KA (1991) Can paleopathology provide evidence for “compassion”? Am. J. Phys. Anthropol. 84:375-384. Fedigan LM and Fedigan L (1977) The social development of a handicapped infant in a free-living troop of Japanese monkeys. In S Chevalier-Skolnikoff and FE Poirier (eds.):Primate Biosocial Development: Biological, Social, and Ecological Determinants. New York: Garland, pp. 205-222. Goodall J (1986) The Chimpanzees of Gombe. Cambridge: Harvard University Press. Gould SJ (1988) Honorable men and women. Natural History 97(3/:16-20.
Notes and Comments The Origins of Caregiving Behavior
Joan B. Silk Department of Anthropology, University of California, Los Angeles, California 90024
I endorse Dettwyler’s (1991) recent critique of claims that the survival of individuals with significant physical impairments is evidence of compassion and moral decency in prehistoric peoples. My goal here is to extend her critique by incorporating evidence about caregiving behavior drawn from the primatological literature. The three main findings that have generated these claims are (1)Shanidar I: an adult male Neandertal who had sustained multiple fractures, suffered a degenerative joint disease, and was probably paralyzed in one arm and blind in one eye, (2) Romito 2: an adolescent Upper Paleolithic male with acromesomelic dysplasia, a condition clinically characterized by severe growth deficiency, dwarfism, bowing of the forearms, and limited extension of the elbows, (3) Windover boy: a teen-ager with spina bifida who lived approximately 7,500 B.P. The survival of these individuals is often said to provide indirect evidence of the compassion of their caretakers, because these individuals would have been hard-pressed to meet their own subsistence needs. Dettwyler identifies five assumptions that implicitly underlie this conclusion, and provides convincing arguments that none of these assumptions are logically compelling or consistent with the ethnographic evidence. She concludes that the fossil record provides no direct, unambiguous evidence of either caregiving or compassion. Here, I extend Dettwyler’s list to include another problematic assumption. While Dettwyler draws upon the ethnographic record to refute the five assumptions she enumerates, I draw upon evidence from the primatological literature to question a sixth assumption i.e., that care for the disabled is unique to Homo sapiens. In his essay in Natural History, Gould (1988)argues that the survival ofthe Romito dwarf:
@ 1992 WILEY-LISS, INC.
offers our oldest evidence for the nurturing and protection-presumably at some expense to the group-of a handicapped individual who was profoundly different from his peers and physically disadvantaged from birth. All other examples of lifelong physical handicaps at this scale date from the origin of agriculture and complex societies (1988:
18).
However, there is reason to believe that the evolutionary origins of such care may lie much further back in time than the Upper Paleolithic. The primatological literature contains a number of detailed accounts of physically impaired individuals who receive substantial amounts of care from other members of their groups. Several of these cases are described below. In the Arashiyama West group of Japanese macaques, an infant was born with gross locomotor deficiencies. Fedigan and Fedigan (1977) provide the following description of his disabilities: Wania 6672 frequently bumped into objects in his environment, such as bushes, cactus, and other monkeys. His movements were spastic, ataxic, and accompanied by continual head dipping. He grasped food clumsily between his thumb and the rest of his hand, showing little manual dexterity , , , when the least bit excited or hurried, as he often was when trying to catch up with his mother, he spun lurched, and fell continually, his hind limbs being especially still and out of control (1977:207).
They also surmised that Wania 6672 was visually impaired, and unable to recognize individuals farther than 10 feet away. The infant’s behavior was substantially different than that of a healthy infant of the same age and maternal rank: he spent more time resting, giving lost infant calls, nursing and seeking comfort, and following his mother, Wania 66. Wania 6672 spent considerably more time in contact with his mother than the healthy infant, and considerably less time playing. Wania 66 allowed her infant to share her feeding site, sometimes allowing him to eat directly from her hand or lap. She also retrieved him more often than other mothers retrieved their infants, and carried him ventrally for 13 months, much longer than other mothers carry their infants in the ventral position. Wania 6672 disappeared
228
J. B. SILK
from the group at about 13months of age; the precise cause of his death is not known. Fedigan and Fedigan conclude that Wania 6672’s survival was “completely due to his mother’s close attention and support. . . Wania not only gave her first-born infant competent care, she gave him extra care” ( 1977:210). It is also notable that other group members seemed to have provided unusual levels of care for Wania 6672. While infants are occasionally retrieved and carried by individuals other than their mothers, Wania 6672 was retrieved by others at considerably higher rates than other infants. Moreover, he was often retrieved by peers who attempted to comfort him by embracing, huddling, grooming, or playing with him. Fedigan and Fedigan note “it was always extraordinary to see such a young monkey leave its companions to hurry over and cradle an infant hardly smaller than itself” (1977:213). In the early 1970s, Berkson (1973, 1977) conducted a series of experimental studies on the effects of visual impairment on the development of young monkeys. For these studies, permanent visual impairment was experimentally produced by making an incision on the pupil which then scarred and produced a cataract. In one study, four infants from a semi-free ranging group on macaques at La Parguera Island were blinded by this procedure. (The experimental protocol, by itself, must make us question the taxonomic bounds for compassion.) For several years, the behavioral development of these infants was monitored and compared to that of normal infants of the same ages. All of the blind infants survived until the age of three years, when the project was terminated. During the first year, blind infants stayed closer to their mothers and were protected by their mothers more often than were normal infants. During the breeding seasons, mothers of both blind and sighted infants often moved out of proximity to their infants. However, “the blind infants were never left alone, and specific members of the group tended to stay near them and carry them if the group moved (Berkson, 1977: 194). Mothers of two blind infants produced infants during the next birth season. These mothers sometimes carried both their yearlings and newborns at the same time, an unusual behavior for female macaques. Among the chimpanzees at Gombe, Goodall (1986) has documented solicitude of sev-
eral individuals who were paralyzed by polio. The first known victim of the polio epidemic was a month-old infant who lost the use of his arms and legs. His mother supported him carefully, cradled him when he became distressed, and carefully protected his limbs. Although his mother continued to care for him, the infant died shortly after contracting the disease. An adult male, Mr. McGregor, lost the use of both legs in the epidemic. While some adult males displayed at him, and some even attacked him, Humphrey, who was believed to have been his brother, behaved solicitously toward him throughout his ordeal. He once charged and attacked a much higher ranking male who had attacked Mr. McGregor. For several days, Humphrey stayed near Mr. McGregor, leaving only long enough to feed. Years later, an old female, who had been partially paralyzed with polio during the epidemic, followed her daughters to a feeding site. When she arrived, she seemed too tired or weak to climb into the vines to feed. Her daughter approached, presented her mother with a piece of fruit, and sat nearby as she fed. Care for motherless infants and young juveniles may also be relevant to the origins of caregiving behavior. Although motherless individuals are not physically disabled, they are not likely to survive if they do not receive some attention from others. Interactions with motherless infants and juveniles range from passive tolerance, to suckling, active support, and protection (reviewedby Thierry and Anderson; 1986). In general, unweaned infants receive care from adult females, and are likely to survive only if their caretaker is lactating. Weaned infants and juveniles are often cared for by older juveniles and adult males (Thierry and Anderson, 1986). Goodall (1986) has observed several cases in which a chimpanzee provided care to an infant or juvenile who was known or suspected to be its sibling. In one case, a fiveyear-old female chimpanzee named Skosha was cared for by Pallas, her mother’s closest companion, after her mother died. When Pallas died, Skosha cared for Pallas’ fiveyear-old daughter, Kristal. Skosha cared for her until Kristal died one year later. These examples are meant to demonstrate that the capacity to provide care for temporarily or permanently disabled individuals is present among nonhuman primates. I do not mean to imply that caregiving is a particularly common form of behavior among monkeys and apes, as reports of such behavior in
229
NOTES AND COMMENTS
the literature are relatively scarce (Cheney and Seyfarth, 1990). The primate literature gives us reason to believe that caregiving behavior antedates the origins of the hominid lineage, but the origins of compassion are considerably harder to date. If “compassion demands some understanding of another’s needs and purposes” (Cheney and Seyfarth, 1990: 2361, then it is problematic to conclude that caregivers are compassionate from their behavior alone. To demonstrate the existence of compassion in monkeys and apes we must demonstrate that they can recognize the physical and emotional needs of other individuals. At present there is no incontrovertible evidence of their ability to do so. In sum, we must have serious reservations about the claim that caregiving is unique t o Homo sapiens. At the same time, we must be cautious about coupling caregiving with compassion among nonhuman primates (or fossil hominids).
LITERATURE CITED Berkson G (1973) Social responses to abnormal monkey infants. Am. J. Phys. Anthropol. 38:583-586. Berkson G (1977) The social ecology of defects in primates. In S Chevalier-Skolnikoff and FE Poirier (eds.): Primate Biosocial Development: Biological, Social, and Ecological Determinants. New York: Garland, pp. 189-204. Cheney DL and Seyfarth RM (1990) How Monkeys See the World. Chicago: Chicago University Press. Dettwyler KA (1991) Can paleopathology provide evidence for “compassion”? Am. J. Phys. Anthropol. 84:375-384. Fedigan LM and Fedigan L (1977) The social development of a handicapped infant in a free-living troop of Japanese monkeys. In S Chevalier-Skolnikoff and FE Poirier (eds.):Primate Biosocial Development: Biological, Social, and Ecological Determinants. New York: Garland, pp. 205-222. Goodall J (1986) The Chimpanzees of Gombe. Cambridge: Harvard University Press. Gould SJ (1988) Honorable men and women. Natural History 97(3/:16-20.
