Signs of Cultural Transmission in a Chimpanzee
Cristy L. Rasmussen, Mary Lee Jensvold, Roger Fouts, Deborah Fouts, & Jason M. Wallin
NOTE: The following are excerpts from a poster Cristy Rasmussen presented at the Rocky Mountain Psychological Association meeting in April, 2008. The entire article can be found in Friends of Washoe Newsletter V29 (4); 9-10
Loulis acquired the signs of American Sign Language (ASL) from his adopted mother and other signing chimpanzees. This poster presents the descriptions of the forms of Loulis’ signs, including new signs acquired since they were last reported in 1994.
As infant chimpanzees, Washoe, Moja, Dar and Tatu were raised like human children and immersed in ASL. They acquired the signs of ASL in patterns that resemble human children (Gardner, Gardner, & Van Cantfort, 1989). In 1979 Washoe adopted 10-month old Loulis. To determine whether Loulis would learn signs from Washoe and other signing chimpanzees without human intervention, human signing in his presence was restricted to seven specific signs, WHO, WHAT, WHERE, WHICH, WANT, SIGN, and NAME. Humans used vocal language to communicate in his presence. Loulis began to sign in 7 days; at 73 months of age his vocabulary consisted of 51 signs (Fouts, 1994). He combined signs into phrases at 15 months of age and these phrases developed in patterns that resembled the cross-fostered chimpanzees and human children (Fouts, Jensvold, & Fouts, 2002). In June 1984 the signing restriction ended and humans began to sign in his presence. This resulted in sign exposure from humans and the other chimpanzees, Washoe, Moja, Tatu, and Dar. Loulis signed to the other chimpanzees (Fouts), to himself (Bodamer, Fouts, Fouts, & Jensvold, 1994), and to his human caregivers.
The ASL signs are described using three aspects. The first aspect is the place (P) where the sign occurs, for example the cheek or chin. The second aspect is the configuration (C) of the hand, for example a fist or flat hand. The third aspect is the movement (M) of the hands, for example contact or up (Gardner, Gardner, & Nichols, 1989). Together they are called the PCM for the sign. For example, Loulis’ PCM for the sign APPLE has the place as “cheek”, the configuration as “curved hand palm up,” and the movement as “knuckles rub down”. A sign is counted in Loulis’ vocabulary when observed and recorded three times (Fouts, 1994). The purpose of this study is to determine new signs in Loulis’ vocabulary since the last publication of his PCMs (Fouts).
When Loulis’ caregivers observed his signs they recorded the behavior in written sign logs. In order to qualify as a sign, a gesture that Loulis made had to resemble the form of an actual ASL sign in place, configuration and movement (PCM). In addition, before it was counted as a sign in Loulis’ vocabulary, the gesture had to be observed and recorded in a written sign log by three different observers on three independent occasions, each in an appropriate context. Caregivers recorded the gesture and context, as well as several accompanying nonverbal behaviors, including arousal level (degree of pilo-erection), body orientation, and eye gaze. If the sign and the nonverbal behavior were consistent with each other and with the referent, then the sign was judged to have been used appropriately (Fouts, Fouts, & Van Cantfort, 1989, p. 284).
For this study research assistants reviewed Loulis’ sign logs and created a database of his PCMs. We selected any sign that appeared on more than three occasions in the database for inclusion in Loulis’s vocabulary list. Two independent judges reviewed the various PCMs for each sign, and decided on the most typical PCM. For each sign, observers agreed on 100% of the PCM description.
Six new signs met the criteria for inclusion in Loulis’ vocabulary. These were GEORGE, ORANGE, CRACKER, SODAPOP, STUPID, and YES. Table 1 lists the PCMs for each of these signs. This table also shows the dates that the sign was first recorded. With these new signs, the total number of signs in Loulis’ vocabulary is 59.
At CHCI, sign language is an important part of interactions between humans and chimpanzees. Sign language is used naturally, as part of conversations rather than in drills as part of explicit instruction. This study shows that Loulis continues to isolate new signs from this stream of linguistic dialogue—across a variety of categories including proper names (GEORGE), foods (ORANGE), and markers (STUPID)—and incorporate them into his vocabulary.
Bodamer, M.D., Fouts, R.S., Fouts, D.H., & Jensvold, M.L.A. (1994). Private signing in chimpanzees. Human Evolution, 9, 281-296.
Fouts, R. (1994). Transmission of human gestural language in a chimpanzee mother-infant relationship. In R. A. Gardner, B. T. Gardner, B. Chiarelli, & F. X. Plooij (Eds.), The ethological roots of culture (pp. 257-270). Netherlands: Kluwer Academic.
Fouts, R. S., Fouts, D. H., & Van Cantfort, T. E. (1989). The infant Loulis learns signs from cross-fostered chimpanzees. In R. A. Gardner, B. T. Gardner, & T. Van Cantfort (Eds.), Teaching sign language to chimpanzees (pp. 280-292). Albany, NY: SUNY Press.
Fouts, R.S. Jensvold, M.L.A., & Fouts, D.H. (2002). Chimpanzee signing: Darwinian realities and Cartesian delusions. In M. Bekoff, C. Allen, & G. Burghardt (Eds.). The cognitive animal: Empirical and theoretical perspectives in animal cognition (pp. 285-292). MIT Press.
Gardner, B. T., Gardner, R. A., & Nichols, S. G. (1989). The shapes and uses of signs in a cross-fostering laboratory. In R. A. Gardner, B. T. Gardner, & T. E. Van Cantfort (Eds.), Teaching sign language to chimpanzees (pp. 55-180). Albany, NY: SUNY Press.
Gardner, R. A., Gardner, B. T., & Van Cantfort, T. E. (1989). Teaching sign language to chimpanzees. Albany, NY: SUNY Press.
Individual- and Task-Variation in Handedness in Five Chimpanzees (Pan troglodytes)
David Blodgett III, Gina Stadtner, Deborah Metzler, Jason M. Wallin, and Robin Potosky (Mentors: Mary Lee Jensvold, Roger S. Fouts, and Deborah H. Fouts)
NOTE: The following are excerpts from a poster David Blodgett III presented at Central Washington University's Syymposium on University Research and Creative Expression in May 2008.The entire article can be found in Friends of Washoe Newsletter V29 (4); 11-13
Humans show a population-level bias in use of the right hand for fine motor tasks such as handwriting (McGrew & Marchant, 1997). Research on handedness in humans and chimpanzees, is important because of its possible connection with the evolution of language. Fouts’ (Fouts & Mills, 1997) theory of language evolution holds that our early hominid ancestors used gestures to communicate. Because gestures often involve both hands, gestural communication likely involved both hemispheres of the brain. When the tongue began to move more precisely and produce words, the hemispheres of the brain were forced to compete for control. This competition resulted in one hemisphere, the left in most humans, controlling of the tongue’s movements for language and for other fine motor movements in the hands such as tool making (Fouts & Mills, 1997). Research on handedness in chimpanzees, may improve this model of vocal communication and brain lateralization in humans.
Free-living chimpanzees show task-dependent biases in hand preference during tool use. Chimpanzees from different groups differentially use one hand for some tasks, such as termite fishing, but the other for nut cracking or wadge-dipping (Lonsdorf & Hopkins, 2005). Steiner (1990) found that captive chimpanzees at the Chimpanzee and Human Communication Institute (CHCI) showed individual hand preferences that varied from task-to-task. For example, Tatu preferred her left hand when eating without a utensil but her right hand when eating with a utensil such as a spoon. In addition to hand preferences in eating with or without an object, Steiner found preferences for manipulating an object, holding an object, grooming, and gesturing using American Sign Language (ASL) (Steiner, 1990).
The current research with the chimpanzees at CHCI follows up on Steiner’s research. It focuses on the chimpanzees’ hand use during gesturing, object manipulation, and food interaction. We hypothesized that 1) the chimpanzees would show individual preferences for one hand or the other and 2) that such preferences would vary within the same individual during different tasks.
Five captive chimpanzees, Washoe, Tatu, Dar, Loulis, and Moja, from Central Washington University (CWU), were the participants of this study. Washoe, Tatu, Dar, and Moja were cross-fostered by R. Allen and Beatrix T. Gardner. They acquired a variety of human behaviors, including ASL. Loulis, Washoe’s adopted son, acquired ASL from Washoe and the other chimpanzees. The chimpanzees have been part of a single social group at CWU since 1981.
The dataset for this study consisted of videotapes of the chimpanzees collected over the past 22 years from their homes at the Psychology Building and CHCI on the campus of CWU.
Coders independently viewed sample segments of videos identifying occurrences of specific arm movements and recording the type of action, the chimpanzee actor, and the hand used. All possible pairwise agreements between coders exceeded 85%.
Washoe, Tatu, and Loulis all showed a right-hand bias. Dar showed a left-hand bias. Moja was ambilateral.
Washoe, Loulis, and Moja preferred their right hands when manipulating objects. Dar preferred his left. Tatu was ambilateral.
Tatu and Dar each used their right hand more often in interactions with food items. Washoe and Loulis did not exhibit statistically significant preferences. Moja was not tested.
This study predicted that the chimpanzees would show a preference in hand use, but that it would differ between individuals and between tasks. These predictions are supported by our results, which also corroborate with Steiner (1990). Human brain lateralization may have evolved with the increasing importance of the tongue (Fouts & Mills, 1997). For chimpanzees, however, the tongue is not particularly important for vocal communication, so we did not expect a clear hand preference to emerge across individuals. Results indicate that chimpanzees are poor models for human handedness. However, in combination with previous studies, these results may reflect a model for chimpanzee handedness. Variations of handedness may not be unique to this family but may also be seen in more general populations.
Fouts, R., & Mills, S.T. (1997). Next of kin. New York: William Morrow and Company.
Lonsdorf, E.V., & Hopkins, W.D. (2005). Wild chimpanzees show population-level handedness for tool use. Proceedings of the National Academy of Sciences of the United States, 102, 12634-12638.
McGrew, W. C., & Marchant, L.F. (1997). On the other hand: Current issues in and meta-analysis of the behavioral laterality of hand function in nonhuman primates. Yearbook of Physical Anthropology, 40, 201-232.
Steiner, S.M. (1990). Handedness in chimpanzees. Unpublished master’s thesis. Central Washington University, Ellensburg, WA.
by Jensvold, M.L., Baeckler S., Fouts R.S., & Fouts, D.H.
EDITOR’S NOTE: This article was presented as a poster at the annual meeting of the International Society of Anthrozoology, in Glasgow, UK on October 6, 2004.
The relationships between captive non-human primates and their caregivers are critical ones and can affect well being. Positive relationships can improve the quality of life; adversely, negative relationships can decrease quality of life. Macaques who had friendly relationships with caregivers were less disturbed by daily laboratory activities (Waitt, Buchanan-Smith, & Morris, 2002) while six minutes of positive interaction between rhesus macaques and a caregiver reduced abnormal behaviors (Bayne Dexter & Strange, 1993). Likewise, when chimpanzees had positive interactions with caregivers they had an overall increase in grooming and a reduction in abnormal behavior and aggression (Baker, 2004). On the other hand, evidence shows a connection between routine husbandry activities and higher wounding rates (Lambeth, Bloomsmith, & Alford, 1997), altered time of parturition (McGrew & McLuckie, 1984; Alford, Nash, Fritz, & Bowen, 1992), and elevated heart rates (Line, Markowitz, Morgan & Strong, 1991) in non-human primates living in laboratories. Furthermore, these individuals often react fearfully and aggressively toward their caregivers (O’Neil, 1989). The mere presence of the caregiver can have a negative effect (Line, Markowitz, Morgan & Strong, 1991).
Rather than the caregivers themselves causing stress, more likely the caregivers’ behavior and the nature of their interactions with their charges is the basis for the stress. Many settings, such as biomedical facilities and entertainment training, are by nature invasive, thus the daily activities will be negative by default. To offset this, some researchers promote operant training techniques (Laule & Whittaker, 2001; Reinhardt& Reinhardt, 2000) to increase cooperation and improve the quality of the relationship. These techniques at times only offer temporary fixes (Bloomsmith, Laule, Alford, & Thurston, 1994). Often the inherent invasiveness in captive settings is taken to an extreme and the relationship between the caregiver and nonhuman primate becomes that of a dominator and subordinate (Estep & Hetts, 1992) and sometimes includes physical punishment or abuse. The Stanford Prison experiment (Zimbardo, 1972), the Abu Ghraib prison, and the Magdalene institutions in Ireland speak to the human potential of slipping into extreme forms of abuse and torture or simply daily teasing and haranguing when in dominant-subordinant relationships. This type of relationship also happens in laboratory (Reinhardt
& Reinhardt, 2002), zoo (Baeckler, 2001), and as described in this study, entertainment settings, and certainly has a negative impact on the individuals living there. However, such stressful situations do not have to be the rule.
Chimpanzees at CHCI
The Chimpanzee & Human Communication Institute (CHCI) at Central Washington University in Ellensburg, Washington is home to chimpanzees who use the signs of American Sign Language (ASL) to communicate with humans and each other. Four of the chimpanzees, Washoe, Moja, Tatu, and Dar were cross-fostered by humans and immersed in an ASL environment much like a child is immersed in a spoken language environment (Gardner & Gardner, 1989). The youngest chimpanzee, Loulis, was adopted and raised by Washoe. Loulis acquired his signs from Washoe and other signing chimpanzees (Fouts, Fouts, & Van Cantfort, 1989).
The heterogeneous backgrounds of these chimpanzees are representative of the diversity within captive populations. These chimpanzees have lived together as a social group since 1981 and Moja died in June 2002.
Approximately 15 student interns and the program directors serve as caregivers and due to the nature of student transiency experienced staff are regularly training new caregivers. The chimpanzees and humans are always separated by a fence and safety protocols are always stressed. The approach to caring for chimpanzees at CHCI is based upon cooperation, respect, and friendship, rather than obedience, fear, and domination. Caregivers operate on principles of reliability, predictability, and respect and operant techniques are never used. They function like domestiques rather than trainers. Different personalities of caregivers and interpersonal attitudes are considered when choosing caregiving staff. The CHCI caregiving staff must be accepted by the chimpanzees. Individuals who elicit aggressive behaviors from the chimpanzees are not allowed to work in proximity to them. Most relationships take time to develop, thus the three month training period is one where experienced caregivers guide and foster a positive relationship between the trainee and the chimpanzees.
Initially all potential caregivers must demonstrate an understanding of chimpanzee behaviors and their meanings. We use a behavioral taxonomy that lists over 200 different chimpanzee behaviors and the contexts in which they occur. Next caregivers are trained in safe procedures for interactions and they incorporate chimpanzee behaviors in all of their interactions. Thus, upon greeting the chimpanzees, a caregiver presents head nods, breathy pants, and a pronated wrist. These behaviors are typical greeting behaviors between free-living chimpanzees.
Chimpanzee groups contain a social hierarchy and CHCI caregivers respect and integrate into this hierarchy. Caregivers treat the alpha chimpanzee with deference. They serve and greet her first which makes it unnecessary for her to assert her dominance. Caregivers also show submissive postures and gestures, such as crouching and avoiding eye contact during aggressive displays to all of the other chimpanzees. This makes the caregivers appear less threatening and reduces their status in the hierarchy. Analysis of the hierarchy at CHCI showed humans held the lowest place (Hayashida et al., 2002). Malone, Fuentes, and Vaughan (2000) examined post-conflict interactions at CHCI. When the chimpanzees directed aggression at another individual following a conflict 63 percent was directed at humans and 37 percent toward other chimpanzees. This is in contrast to a biomedical facility where 22 percent of aggression was directed at unfamiliar humans and 78 percent toward other chimpanzees (Maki, Alford,& Bramblett, 1987). Since humans are the lowest ranking individuals at CHCI they are safe outlets for aggression. At other facilities chimpanzee aggression is inhibited by enclosure design (Rumbaugh, 1988) or punishment.
At CHCI, as part of regular husbandry practices, caregivers observe the chimpanzees daily and record any wounds they observe into a medical log. The records include a description of the wound and its location. For this report, wounds recorded between July 1993 and July 2000 were classified as either minor or serious. Minor wounds were characterized as scratches, bruises, abrasions, or cuts smaller than 0.5 inch in length or diameter. Serious wounds were larger than 0.5 inch in length or diameter, puncture wounds, bites, or wounds deeper than the surface of the skin.
Table 1. Total Number of Minor and Serious Wounds per Chimpanee at CHCI from 1993 - 2000.
As seen in Table 1, each chimpanzee averaged 0.971 minor wounds and 0.457 serious wounds per year. The total average for each chimpanzee per year was 1.43 for all types of wounds over the 7-year period. A group of 136 chimpanzees at the Yerkes Regional Primate Research Center in Atlanta, Georgia incurred 965 wounds over the two-year period from August 1995 to August 1997 (Bake, Seres, Aureli, & deWaal, 2000). The average for each chimpanzee per year was 3.55 wounds, this rate is 2.5 times higher than CHCI. Lambeth, Bloomsmith, and Alford (1997) reported the wounding rates of a group of 88 chimpanzees (42 female, 46 male) at the University of Texas M.D. Anderson Cancer Center Science Park (UTSP) over approximately a 10-year period. The average for each chimpanzee per year was 4.5 wounds, this rate is 3 times higher than CHCI. This difference in wounding rates may reflect the social hierarchy and the direction of aggression. By allowing the chimpanzees to aggress in safe ways toward humans, the other chimpanzees in the group gain some protection.
Routines and Predictability
The chimpanzees begin each day in their nighttime enclosure with a greeting from a friend and they return the blankets and other nighttime enrichment to the caregiver. Next the caregiver serves breakfast, which is vitamins, monkey chow, a fruit smoothie, and whole fruit. Then, they enter the indoor and outdoor playrooms where there are toys, clothes, magazines, and other objects to enrich the environment. At noon the caregiver offers a lunch of monkey chow, a cooked bean and vegetable soup, and fresh vegetables in the night enclosures. Those who wish to eat enter the night enclosure. After lunch they are allowed back into the playrooms. At the end of the day the caregiver offers dinner in the nighttime enclosures. Dinner is usually monkey chow and cooked cereal, potatoes, or some other carbohydrate based entrée. Once again those who wish to eat enter the night enclosure. After dinner, caregivers distribute blankets and nighttime enrichment such as toys, magazines, hairbrushes, and toothbrushes in the night enclosures. The chimpanzees stay there until the following morning. If a chimpanzee chooses not to eat dinner, he or she may sleep in one of the playrooms.
The regular movement of the chimpanzees ensures that each enclosure is vacant during a 24-hour period, usually at a regular time, and then the caregivers can enter the vacant enclosure to clean it. From the chimpanzees’ perspective they have a predictable sequence of events and they can choose to participate or not participate in an event. This provides the chimpanzees with a sense of control and choices in their daily activities and they are not punished for lack of participation. Sometimes the chimpanzees’ participation is essential for the routine to continue. Then the choice for the chimpanzees is to have the routine continue or not. For example, in the morning caregivers ask the chimpanzees to return their blankets before breakfast begins and breakfast does not begin until the blankets are returned. This is much like starting the car in the morning, the key must be inserted and turned before the car starts. In contrast, at many zoo and laboratory settings caregivers yell at or threaten the chimpanzees who do not comply with requests (Baeckler, 2001). When the chimpanzee’s interests are a priority, relationships between chimpanzees and caregivers are much more harmonious. Alternately, when the human’s needs are a priority, a constant conflict exists between chimpanzees and caregivers. Our system circumvents that situation.
For this method to work it is important for staff to be consistent and follow the same set of rules. Failure to do this introduces unpredictability and robs the chimpanzees of their ability to choose. If a staff person does not follow the routine and makes up his or her own routine, then the chimpanzees are unable to predict consequences and make choices.
Baeckler (2001) compared caregiving techniques and interactions between chimpanzees and their caregivers at CHCI, the Honolulu Zoo in Honolulu, Hawaii (HZ), and the Oregon Zoo in Portland, Oregon (OZ). At both zoos the chimpanzees and caregivers were always separated by fencing. At HZ the caregiver had no prior training or understanding of chimpanzee behaviors and his interactions with the chimpanzees were forceful including yelling, withholding food, and spitting at the chimpanzees. The chimpanzees demonstrated a marked lack of cooperation with the caregiver. In turn the morning routine varied each day depending on which chimpanzees would comply with the caregiver’s commands.
The caregiver at OZ had no formal training in chimpanzee behaviors but had 28-years of experience working with the OZ chimpanzees. This facility had a highly restricted physical and social space thus the chimpanzees’ social groups were constantly rotated and the daily pattern of the chimpanzees’ access to certain areas and to other chimpanzees was unpredictable.
Baeckler (2001) systematically recorded the context of social interactions at all three facilities. Ninety percent of the aggressive interactions occurred at HZ. Eighty-three percent of the affinitive social interactions occurred at CHCI. Of the play interactions, 62 percent occurred at OZ, 32 percent at CHCI, and only 5 percent at HZ. Social interactions between the chimpanzees were observed less frequently at OZ than at the HZ and CHCI, which was most likely due to the limited physical and social space.
The dominating style of the HZ caregiver is reflected in the high level of threat behaviors and lack of affinitive social behaviors displayed by the chimpanzees. The caregiver was not integrated into the chimpanzee social group and the chimpanzees did not spend significant amounts of time cooperating nor interacting with him. In contrast, at times the chimpanzees at OZ were confined to a small area and they had no choice but to interact and cooperate with the caregiver. At HZ and CHCI the chimpanzees had the space to walk away from their caregivers at any time, which allowed them to maintain some control of their social interactions. Both zoos lacked a predictable routine, thus the chimpanzees had very few choices in daily activities. Neither caregiver used chimpanzee behaviors nor integrated into the chimpanzee hierarchy. This may have been due to a lack of education. One caregiver gained cooperation through domination and threats. This created an environment that lacked positive interactions and reduced their quality of life.
A facility in Malibu, California trained chimpanzee “actors” for appearances in film and television which required a high degree of cooperation from the chimpanzees, who were all under the age of seven. The following results are from a study conducted at this facility by one author using an undercover participant observation approach. These methods are within the general guidelines set for undercover research in a hostile environment. The caregiving staff had no training in natural chimpanzee behaviors. They never gave the chimpanzees a choice about their activities and they used physical force and intimidation to maintain the daily routine. In contrast to CHCI, OZ, and HZ, the chimpanzees were removed from their enclosures for interactions with humans and training sessions. If a chimpanzee did not cooperate, caregivers used physical punishment. For example, they struck the chimpanzees with fists, rocks, and broom handles. As a result, the chimpanzees were fearful of the primary caregiver and when they saw him approaching they often screamed and sought reassurance from each other. Chimpanzees were frequently observed engaging in stereotypic rocking and often screamed and fear grimaced during training sessions. The extreme domination created a very stressful and negative environment, which is in marked contrast to CHCI and the zoo settings.
To improve the quality of life by creating a more harmonious and less stressful environment for chimpanzees, we recommend:
- An understanding and use of chimpanzee behaviors.
- A servile, submissive, and respectful attitude toward the chimpanzees which places humans lower on the chimpanzee hierarchy.
- A predictable daily routine.
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