Gardner and Gardner (1969) Aims

Transcription

1 Gardner and Gardner (1969) Aims In this study, Gardner and Gardner sought to establish whether a non-human primate - a chimpanzee - could learn a language used by humans. In addition, as previous studies had failed to teach chimpanzees to vocalise like humans, Gardner and Gardner tested the use of a signed human language. This was considered to be more appropriate because a chimp s vocal apparatus is probably not sufficiently developed to make human sounds. Context Why do psychologists investigate animal language in primates? One reason is that research on animals has helped psychologists understand more about human behaviour. For example, work by Harry Harlow with rhesus monkeys in the 1950s was influential because it demonstrated that rhesus infants were less likely to thrive psychologically if they were deprived of emotional comfort (e.g., Harlow, 1959). This research clearly had important implications for human child rearing. Research with chimpanzees in particular can help us increase our understanding of human behaviour because we share a large percentage of our genetic make-up with these animals. Therefore, studying language acquisition in a chimpanzee could help clarify the mechanisms involved in human language acquisition. Furthermore, such research could also help ascertain which aspects of language are unique to humans, or indeed, whether language is solely a human activity. The study of language in animals has a long tradition and is, in fact, one of the oldest research areas in psychology. An early attempt to teach a chimpanzee human language was carried out by Winthrop and Luella Kellogg during the 1930s and their findings were published in a book (Kellogg and Kellogg, 1968) many years later. A 7½ month old chimpanzee called Gua was introduced into the Kellogg household and was brought up in an identical fashion to the Kellogg s son Donald. As the study progressed, both Donald and Gua had daily tests for nine months both physical and psychological in order to chart their development. In terms of vocal communication, Donald was always superior even from a young age, whereas Gua maintained those vocal responses she possessed at the start of the study. What was surprising, however, was that initially Gua was superior in her understanding of simple words. Nevertheless, by the end of the nine month testing period, Donald had surpassed her in comprehension. This initial study, therefore, seemed to provide evidence in support of the idea that language is unique to humans.

2 This conclusion was supported by a later study by Keith and Catherine Hayes in the 1950s (Hayes and Hayes, 1952). The research subject in this case was a chimpanzee called Viki. Viki went to live in the Hayes home when she was a baby and was also brought up as if she was a human child. In the course of her upbringing, Hayes and Hayes repeatedly tried to encourage Viki to speak by a system of reinforcement but after six years she could only produce four words (mama, papa, up, cup). Even then, only the Hayes family was able to understand Viki and she also had to hold her lip to make the vocalisations. Taken together, the results of the Hayes study and the Kelloggs study appeared to suggest that human language capabilities were not present in chimpanzees. However, in the 1960s, Allen and Beatrice Gardner suggested that this conclusion was premature because chimps do not have the sophisticated vocal apparatus of a human. They therefore attempted to overcome this limitation by using a human language that was signed. Procedure For their study the Gardners used a chimpanzee called Washoe. Washoe had been born in Africa and had been captured by the US airforce for research purposes. She was transported to America and was around 8-14 months old when she arrived at the Gardners laboratory. It was decided that American Sign Language (ASL) should be used as the medium of communication between Washoe and those who interacted with her daily. Washoe always had a human companion during her waking hours and the companions worked on a shift system. All the companions had to learn ASL and they were instructed to use it in Washoe s presence as if they were a human parent talking to a child. Continuous signing in her presence was therefore a strategy designed to help Washoe understand signs. Therefore, whenever she was paying attention, her companion would name as many objects and activities as possible and also introduce new signs to Washoe. Throughout the study Washoe was allowed a lot of freedom and was rarely confined. She was treated like a human child and she engaged in games and activities with her companions. Part of Washoe s language training centred around the process of imitation. Once Washoe had started to acquire signs, imitation on command was used to prompt her and also to increase and improve her signing. For example, if Washoe used a new sign in an inappropriate context or used an old sign incorrectly, her companion would repeat the sign until Washoe imitated it correctly. Sometimes Washoe used poor diction when signing. In this situation, her companion would make the correct sign until Washoe repeated it in its correct form. In order to determine whether Washoe had successfully acquired a sign, certain criteria had to be fulfilled. Firstly, the sign had to be used by Washoe in the right

3 situation and also it had to be spontaneous. Secondly, the sign had to be used at least once every day for fifteen consecutive days. This period of fifteen days only started when three different observers reported they had seen spontaneous and appropriate usage of the sign. Findings In the initial stages of the project, there was considerable difficulty getting Washoe to imitate on command. However, after 16 months of hard work by her companions, she finally began to respond. Nevertheless, this process did not always run smoothly because Washoe was prone to running away and throwing tantrums if her companion was pressing too hard for the required sign. Sometimes, she would also bite her companion if she was particularly frustrated at being asked to imitate a sign. Despite these problems, Washoe made considerable progress in her language learning. One way in which this was demonstrated was by Washoe exhibiting delayed imitation. One of her routines included brushing her teeth after meals and, although she made a fuss about this initially, she gradually became used to it and was happy to brush her teeth. Whenever a teeth brushing session occurred, the companion would use the sign for toothbrush. Initially it was not clear if Washoe could use this sign as no-one had seen her use it. However, at one stage in the project, she was in the Gardners home and whilst in the bathroom she spontaneously made the sign for toothbrush when she observed a mug of toothbrushes. This was an example therefore of delayed imitation and was one of the first indications that Washoe could use signs purely for communication purposes rather than merely copying. Washoe also showed delayed imitation for the flower sign. She particularly loved flowers and one day whilst in a flower garden she spontaneously made the sign. This again was evidence that she could use signs as a means of communication. As the project progressed, her repertoire of signs gradually grew and after 22 months she could use 30 signs appropriately. In addition, from the period where she knew around 10 signs, she spontaneously began to use them in strings of 2 or more as if she was putting simple sentences together. Conclusions The Gardners concluded that human sign language is an appropriate medium in human-chimpanzee communication and that Washoe demonstrated the capability for learning and using a human language. What was particularly striking was her ability to spontaneously combine signs. It could be argued that this is highly similar

4 to the simple word combinations used by human children in the early stages of language learning. Consequently, it appears that Washoe was able to grasp some of the rules of human language. Evaluation This research used the case study approach whereby a single individual is investigated over a period of time. The benefit of this approach is that a more detailed, in-depth investigation of the research question is possible. For this study, therefore, the progression in Washoe s language acquisition could be tracked in detail. The case study is also useful in exploratory studies as the information gathered can be used to test out the effectiveness of new research procedures. In the context of the Gardners study, the researchers acknowledged that their procedures needed to be refined and extended. For example, they outline in their article a new procedure for testing Washoe s object naming ability. In this procedure objects are placed in a box with a window and Washoe is questioned about the contents of the box by an observer who cannot see inside. By using this procedure, the Gardners hoped to assess whether Washoe could use the appropriate human language rules in such situations. Nevertheless, despite the advantages of the case study approach, this type of research method can be costly. Firstly, it can be costly in terms of expense. In the Gardners study, it is highly likely that the costs of looking after Washoe and paying those involved were quite extensive. Secondly, case studies can be costly in terms of time. The Gardners project took place over many months and all involved had to wait a considerable amount of time before Washoe began to show signs of language acquisition. Consequently, testing theories using a case study approach can be a long and laborious process. The study can also be criticised in terms of its ethics. On the negative side, there are a number of issues regarding the use of Washoe as a research subject. To begin with, Washoe did not have the ability to say whether she wanted to take part or not. An important question therefore is whether animals have the same rights as human participants. Some researchers such as Regan (1983) have argued that they do have the same rights, that scientists should accept this and that they should therefore avoid the use of animals in their research. Another ethical problem with this study is that when Washoe was around five years old she was sent by the Gardners to the University of Oklahoma to be used as a research subject in another project. We can only speculate about the psychological impact this had on Washoe but it is highly likely that she suffered some distress at having to leave behind her home and the human companions she was close to. Having said this, however, she was accompanied by Roger Fouts, one of the researchers who had been studying her

5 whilst she was involved in the Gardners project. Indeed, Fouts was one of her main carers until she died. As a result, some care was taken to protect Washoe in her transition from the Gardner project to her new home in Oklahoma. Related studies Research into language learning by non-human primates became increasingly more prolific after the Gardners study with Washoe. One very famous piece of research has been conducted by Penny Patterson in a project that is still continuing to this day. Patterson s research began in 1972 when she started working with a one-year old gorilla called Koko. Koko s language teaching involved being exposed to both ASL and spoken English but the aim was for Koko to communicate using ASL only. This again was due to vocalisation limitations in apes. Koko was taught through imitation and through moulding her hands into the appropriate signs and, as a result of this training, Koko has acquired an incredibly large vocabulary of around 1000 signs. As well as this, she can understand around 2000 words of spoken English. From her work with Koko, Patterson has speculated that language in humans may originally have been gestural because at some time in evolutionary history our anatomy would not have been developed enough to generate speech. At around the same time as Patterson s research and the Gardners research began, two researchers called Ann and David Premack had started to teach language to a young chimpanzee called Sarah. This study differed to both Patterson s and the Gardners study, however, in that Sarah was not taught a gestural language but instead was instructed to use tokens that could stick to a magnetic board. The tokens did not resemble the objects they represented, e.g., banana was represented by a square. In order to increase Sarah s use of more complex sequences, she was given rewards where appropriate. In their first report about Sarah (Premack and Premack, 1972), she had acquired the ability to use 130 language structures with a reasonable amount of accuracy. As a result of this research the Premacks asserted that Sarah was comparable in language ability to a human child. This observation mirrors the findings of Patterson and the Gardners and therefore provides further evidence that certain features of human language, i.e., making simple constructions, can be acquired by non-human primates. One of the more recent and most astonishing accounts of language acquisition in non-human primates has been reported by Savage-Rumbaugh (1990). In this investigation a young bonobo (or pygmy chimpanzee) monkey called Kanzi exhibited remarkable linguistic skill. Initially, Kanzi had no formal language training but he accompanied his adoptive mother Matata when she went to her language training sessions. These sessions were structured around Matata learning language via lexigrams (symbols) on a keyboard. Matata struggled during the sessions and

6 eventually only learned a few signs. However, when Kanzi himself was ready to be trained to use the lexigrams, he astonished Savage-Rumbaugh by spontaneously using the keyboard to communicate thus suggesting that he had been surreptitiously studying the lexigrams when his mother was learning them. Since then, Kanzi has gone on to add many more lexigrams to his repertoire. Also, when presented with a spoken word over headphones, he can point to the correct lexigram thus indicating his ability in understanding spoken English. What is particularly fascinating about Kanzi is the way in which he makes novel combinations of lexigrams to communicate. Even more fascinating is the fact that, unlike Washoe, Koko and Sarah, he received no formal language training. Instead, he was reared in a language-rich social atmosphere in which his human caretakers regularly spoke to him, and in naturalistic surroundings that mirrored the bonobo natural environment. As a result, Savage-Rumbaugh has asserted that Kanzi has been exposed to language learning in a way that is highly similar to that of a human child. This has, in consequence, led to Kanzi acquiring the linguistic ability of a three-year old child. Greenfield and Savage-Rumbaugh (1991) have therefore suggested that, in terms of evolution, humans and chimpanzees share some linguistic abilities as a result of their distant, common ancestry. Naturally, such an assertion challenges the idea that language is purely a human activity. Gardner, R.A. & Gardner, B.T. (1969). Teaching sign language to a chimpanzee. Science, 165,