Chimpanzee Signing: Darwinian Realities and Cartesian Delusions

Home , Deborah Fouts, Loulis, Movement (sign language)

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Anthropology and Museum Studies Faculty Scholarship College of the Sciences

2002

Roger S. Fouts

Mary Lee A. Jensvold

Deborah Fouts

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The Cognitive Animal Empirical and Theoretical Perspectives on Animal Cognition

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The title-level DOI for this work is: doi:10.7551/mitpress/1885.001.0001 35 Chimpanzee Signing: Darwinian Realities and Cartesian Delusions

Roger S. Fouts, Mary Lee A. Jensvold, and Deborah H. Fouts

(ASL) in Washoe’s presence (B. T. Gardner and Darwinian Realities Gardner 1971, 1974, 1989; R. A. Gardner and Gardner 1969). Truly discontinuous, all-or-none phenomena must be rare in nature. Historically, the great discontinuities In teaching sign language to Washoe [and other later have turned out to be conceptual barriers rather than cross-fosterlings] we imitated human parents teaching natural phenomena. They have been passed by and young children in a human home. We called attention abandoned rather than broken through in the course of to everyday events and objects that might interest the scientiﬁc progress. The sign language studies in chim- young chimpanzees, for example, THAT CHAIR, SEE panzees have neither sought nor discovered a means PRETTY BIRD, MY HAT. We asked probing ques- of breathing humanity into the soul of a beast. They tions to check on communication, and we always tried have assumed instead that there is no discontinuity be- to answer questions and to comply with requests. We tween verbal behavior and the rest of human behavior expanded on fragmentary utterances using the frag- or between human behavior and the rest of animal ments to teach and to probe. We also followed the behavior—no barrier to be broken, no chasm to be parents of deaf children by using an especially simple bridged, only unknown territory to be explored. (R. and repetitious register of ASL and by making signs Gardner et al. 1989, p. xvii) on the youngsters’ bodies to capture their attention. (R. A. Gardner and Gardner 1998, p. 297) Cross-Fostering In 1970 Washoe left Reno with companions While chimpanzees (Pan troglodytes) have great Roger and Deborah Fouts for the Institute of di‰culty adapting their vocalizations to human Primate Studies (IPS) at the University of Okla- speech (Hayes and Hayes 1951; Hayes and Nis- homa in Norman. The Gardners began a second sen 1971), they can freely move their hands, cross-fostering project with four other infant meaning that a gestural language is well suited to chimpanzees. Moja, Pili, Tatu, and Dar were their abilities. R. A. and B. T. Gardner recog- born in American laboratories and each arrived nized this in their sign language studies with in Reno within a few days of birth. Moja arrived young chimpanzees. In 1966, the Gardners in November 1972 and cross-fostering continued brought 10-month-old Washoe to the University for her until the winter of 1979 when she left of Nevada-Reno when they began their cross- for IPS. In 1980, Washoe and Moja moved with fostering study. The Gardners described this the Fouts to the Chimpanzee and Human Com- approach as follows: munication Institute (CHCI) on the campus of Central Washington University in Ellensburg, Cross-fostering a chimpanzee is very di¤erent from Washington. Tatu arrived in Reno in January keeping one in a home as a pet. Many people keep pets 1976 and Dar in August 1976. Cross-fostering in their homes. They may treat their pets very well, and continued for Tatu and Dar until May 1981, they may love them dearly, but they do not treat them when they left to join Washoe and Moja in like children. True cross-fostering—treating the chim- Ellensburg. Pili arrived in Reno in November panzee infant like a human child in all respects, in all living arrangements, 24 hours a day every day of the 1973 and died of leukemia in October 1975. year—requires a rigorous experimental regime that has The size of the chimpanzees’ vocabulary, rarely been attempted. (R. A. Gardner and Gardner their responses to Wh- questions (where, why, 1998, p. 292) when etc.), number of utterances, proportion of phrases, variety of phrases, length of phrases, The Gardners and students in the cross-fostering complexity of phrases, and inﬂection all grew project used only American Sign Language R. S. Fouts, M. L. A. Jensvold, and D. H. Fouts 286

Figure 35.1 Number of phrase tokens. throughout 5 years of cross-fostering (R. A. second month. From this record we plotted the Gardner et al. 1992; B. T. Gardner and Gardner growth of Loulis’s phrases. A phrase is two or 1974, 1989, 1998). ‘‘Washoe, Moja, Pili, Tatu, more di¤erent signs within two utterance boun- and Dar signed to friends and strangers. They daries. Utterance boundaries are defined by a signed to each other and to themselves, to dogs pause marked by a relaxation of the hands with- and to cats, toys, tools, even to trees’’ (R. A. in the signing area, or dropping the hands from Gardner and Gardner 1989, p. 24). Signing was the signing area altogether. The observer indi- a robust behavior in the chimpanzees. cated utterance boundaries in the field records with a slash. Reiteration, where a sign is repeated Cultural Transmission for emphasis, did not meet the requirement for a phrase in that it did not contain two di¤erent At CHCI we continued to explore how the signs. chimpanzees acquired signs and used them to Phrase tokens provide information on the fre- communicate with humans and each other. The quency of all phrases that appeared in a year. first of these studies began in 1978. In 1979, YOU CHASE and CHASE YES are examples Washoe adopted a 10-month-old son, Loulis. To of two di¤erent phrase tokens. When Loulis show that Loulis would learn signs from Washoe signed ME ME GOOD GOOD once on March and other signing chimpanzees without human 1, 1984 and ME ME GOOD GOOD once on intervention, we restricted human signing when May 28, 1984, this was counted as two tokens. Loulis was present except for seven specific signs, Figure 35.1 shows the total number of phrase WHO, WHAT, WHERE, WHICH, WANT, tokens recorded for Loulis each year. Loulis’s SIGN, and NAME. Humans used vocal English pattern is similar to that of Moja in figure 2 of B. to communicate in his presence. Loulis began to T. Gardner and Gardner (1998). sign in 7 days; at 15 months of age he combined We grouped phrase tokens into types accord- signs; and at 73 months of age his vocabulary ing to the signs that they contained regardless of consisted of 51 signs (R. S. Fouts 1994; R. S. the order of the signs in the utterance. For exam- Fouts et al. 1982, 1989). ple, all phrases that contained the signs THAT Human observers maintained written records HURRY, HURRY THAT, and THAT THAT of Loulis’s signing and behavioral development. HURRY HURRY THAT THAT were the same We used all of the records from his tenth month phrase type containing the two signs HURRY (the first month of the project) to his seventy- and THAT. This provides information on the Chimpanzee Signing 287

Figure 35.2 Number of phrase types: two sign phrases.

Figure 35.3 Number of phrase types: three or more sign phrases. variety of phrases that Loulis produced. Figure acquisition of phrases is particularly impres- 35.2 shows the total number of phrase types re- sive since it occurred in the absence of human corded for Loulis each year. After the third year signing and his only models were other signing of the project, Loulis showed a steady increase in chimpanzees. the variety of his phrases. This pattern was similar to that of Moja, Tatu, Pili, and Dar in ﬁgure Remote Videotaping 3 of B. T. Gardner and Gardner (1998). Figure 35.3 shows the development of phrase types with In June 1984, the restriction on signing around three or more signs for Loulis. An example is Loulis ended and we turned our attention to HURRY YOU TICKLE. After the fourth year recording Loulis’s use of signs by remote video- of the project, there was a sharp increase in the taping, a technique that allowed the behavior of variety of Loulis’s three or more sign phrases. the chimpanzees to be recorded with no humans Loulis’s phrase development paralleled that present. In the original method, three cameras of the cross-fostered chimpanzees. Like human were mounted in a chimpanzee enclosure, with children, the development of phrases grew grad- each focused on part of the enclosure. Later a ually in Loulis and the cross-fostered chimpan- fourth camera was added. The cameras were zees (B. T. Gardner and Gardner 1998). Loulis’s attached to television monitors and to a video- R. S. Fouts, M. L. A. Jensvold, and D. H. Fouts 288

cassette recorder (VCR) in another room away ance that refers to an object or event that is not from the chimpanzees. Only one camera recorded present, accounted for 12 percent in the 56-hour at a time and the VCR operator could control sample and 14 percent in the 45-hour sample. An which camera recorded. example of an utterance in this category was D. H. Fouts (1994) made 45 hours of remote when Washoe signed DEBBI to herself when videotape recordings to examine Loulis’s inter- Debbi was not present. actions with Washoe, Moja, Tatu, and Dar. One category of private signing was imagina- Loulis initiated 451 interactions, both signed and tive and accounted for 17 instances in the 56 nonsigned, with the other chimpanzees. Forty hours of remote videotaping. We later recorded percent (181) of those interactions were directed 15 hours of remote videotape while the chimpan- to his male peer, Dar. Loulis used 206 signs in zees’ enclosure was filled with toys. We found six his interactions and 114 of those were directed instances of imaginary play. We classified these toward Dar. D. H. Fouts (1994) also reported into categories of imaginary play that human 115 private signs that Loulis made when his face children use (Matthews 1977). There were four and body were not oriented toward another instances of animation in which the chimpanzee chimpanzee. treated an object as if it was alive. For example, Loulis signed to the other chimpanzees and Dar signed PEEKABOO to a stu¤ed bear. There they signed to each other as well. A later study were four instances of substitution in which the by Cianelli and Fouts (1998) found that the chimpanzee treated one object as if it were an- chimpanzees often used emphatically signed ASL other. For example, Moja wore a shoe and signed signs during high-arousal interactions such as SHOE. She then removed the shoe, put a purse fights and active play. For example, after sepa- on her foot, and zipped it up (Jensvold and rating Dar and Loulis during a fight and with all Fouts 1993). the chimpanzees still screaming, Washoe signed Williams (1995) used remote videotaping to COME HUG to Loulis. Loulis signed NO and examine the five chimpanzees’ nighttime behav- continued to move away from Washoe. These ior. The chimpanzees were more active at night results indicate that the chimpanzees’ signing is than we previously had assumed. There were very robust indeed and is a regular part of their even a few instances of signing in their sleep. interactions. Bodamer (1987) looked for instances of pri- Conversational Context vate signing by the other chimpanzees in the videotapes recorded by D. H. Fouts (1994). He While remote videotaping provides a way to found 90 instances of private signing. These were discover what the chimpanzees do in the absence signs made in the absence of interactive behav- of humans, at other times we are interested in iors, such as looking toward another individual. controlling variables and measuring the chim- He classified these into categories of private panzees’ responses within the context of their speech that humans use (Furrow 1984). We later typical daily signed interactions with their hu- recorded 56 more hours of remote videotape and man caregivers. This is the legacy of the Gard- found 368 instances of private signing (Bodamer ner cross-fostering project; they used rigorous et al. 1994). In both samples, one of the most methodology within the usual routine of the common categories of signing was referential (59 cross-fostering environment. In the Gardner ex- percent in the 56-hour sample). In this category periments and in our own, the chimpanzees were the chimpanzee signed about something present free to leave the testing situation and to respond in the room, for example, naming the pictures in to their world with their full repertoire of be- a magazine. The informative category, an utter- haviors. Typically in comparative psychology Chimpanzee Signing 289

the experimenter tests the participant in an arti- enclosure to request objects or activities. They ficial environment in order to control all vari- often made noises if the human was not looking ables. However, this so greatly removes the at them. Bodamer and Gardner (2002) system- participant from his or her natural environment atically studied these initiations. The interlocutor that we often discover more about the intelligence sat in the workroom with his back toward the of the experimenter than that of the participant. chimpanzees’ enclosure. When the chimpanzee The following studies were all conducted during made a noise, he turned and faced the chimpan- naturally occurring signing interactions between zee immediately or after a 30-second delay. the chimpanzees and their human caregivers When the interlocutor was not facing the chim- without compromising methodological controls. panzees, they made noises, such as Bronx cheers, The PCM system (B. T. Gardner et al. 1989) and rarely signed. The few times the chimpan- describes how a sign is formed, using place where zees signed, they used signs that made noise, the sign is made, configuration of the hand, and such as DIRTY, in which the back of the hand movement of the hand. During everyday activ- hits the bottom of the jaw. Closed with force, ities such as cleaning, meals, and playtime, Davis this sign is noisy. In the delayed-response con- (1995) introduced a distortion in some of her dition, the noises became louder and faster. Once signs to measure the chimpanzees’ response to the interlocutor faced the chimpanzees, they the mispronunciations. The distortions always stopped making sounds and signed. Using a occurred on the place of the sign. Low distor- naturally occurring situation, this experiment tions were made 1 to 4 inches from the standard showed that the chimpanzees initiate interactions form of the sign. Medium distortions were made and sign spontaneously. 5 to 8 inches from the standard form of the sign. In another test of conversational skill, the High distortions were made 9 to 12 inches from interlocutor used one of four types of probe: the standard form of the sign. For example, the general questions, on-topic questions, o¤-topic standard form of the sign CRACKER is a fist questions, or negative statements (Jensvold and hitting the elbow. In low distortion the fist hit the Gardner 2000). When the interlocutor asked a forearm; in medium distortion the fist hit the general question, the chimpanzees frequently ex- wrist; and in high distortion the fist hit the fore- panded across turns, showing a persistence in head. In response to low distortion messages, the their original topic and giving the interlocutor chimpanzees restored the sign to its original more information. When the interlocutor asked form. When the distortion was high or medium, a relevant on-topic question, the chimpanzees they typically did not respond. Like humans, the responded with many incorporations and ex- chimpanzees are tolerant of slight mispronuncia- pansions. These responses are indicators of topic tions of signs. When the mispronunciation in- maintenance. When the interlocutor asked an creased, the chimpanzees’ responding decreased. o¤-topic question, the chimpanzees often failed This study used naturally occurring interactions to respond and when they did respond, they used with a human interlocutor to test the chimpan- few incorporations and expansions. When the zees’ perception of semantics. Other experiments interlocutor made a negative statement, Washoe tested pragmatic aspects of the chimpanzees’ and Dar often did not respond. The chimpan- signed interactions with humans. zees’ responses were contingent and appropriate At the original CHCI facility, the chimpanzees to the interlocutor’s questions or statements and had access to a suite of enclosures. One of the resembled patterns of conversation found in enclosures was across the hall from a human similar studies of human children. workroom. When a caregiver was in the work- By using rigorous methods that allow the room, the chimpanzees often came to the nearby chimpanzees to demonstrate their behaviors in R. S. Fouts, M. L. A. Jensvold, and D. H. Fouts 290

a context-appropriate situation, sign language play about things that were present as well as not studies of chimpanzees show remarkable sim- present. They initiated interactions with humans ilarities between human and chimpanzee behav- and appropriately adjusted their answers to vari- iors. These similarities support the biological ations in the interlocutor’s signs and questions. reality that species di¤er by degree. Sign language studies ﬁll some of the gaps between humans and the rest of nature that were created in the minds of philosophers and are Future Research maintained by human arrogance.

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