A Level Psychology at Spalding Grammar School

Savage-Rumbaugh et al. (1986) Spontaneous symbol acquisition & communicative use by Pygmy Chimpanzees

Your second approach to study is the Cognitive Approach. You will need to bring your notes and answers to class to be assessed on your understanding of the study.

 

1986 was a very confusing year for Kanzi's hairless cousins. The tool-using apes had a real love-afair with technology, with Tom Cruise's air force adventure Top Gun ruling the box office and electronica dominating the charts: Falco's Rock Me Amadeus, the Pet Shop Boys' West End Girls and the swirling synths of The Final Countdown by Europe. Meanwhile, technology was biting back - the space shuttle Challenger exploded killing 7 astronuts and the nuclear power station at Chernobyl exploded a radioactive cloud across Europe. The final countdown, indeed....

 

The study by Sue Savage-Rumbaugh et al. is a longitudinal study, working with two pygmy chimpanzees (bonobo apes) and trying to teach them to use language. The point of this research is that the apes would use language SPONTANEOUSLY – without being trained or prompted. It would be helpful if you knew some of the earlier research that trained apes to communicate with rewards, such as Project Washoe by Alan & Beatrix Gardner in the ‘60s.

Download your study materials

Click here for making notes on this study.Click here to see the assessment questions you need to answer on this study. Click here to view a PowerPoint slide show guiding you through the study.

Access these web resources

Look at Holah's study guide - which contains a link to the complete text of the original study

Or look at PsychBLOG's article "The Apes That Can"

Visit Sue Savage-Rumbaugh's homepage which has videos of her and Kanzi - then browse around the Great Ape Trust's site for more ape-stuff

Read Kanzi's biography on Wikipedia

Read an interview with Sue Savage-Rumbaugh talking about Kanzi or listen to a Radio 4 programme on her research

Extension work: further your understanding

Listen to this podcast of an interview with Sue Savage-Rumbaugh or watch this YouTube video of Kanzi using the lexigrams . Finally, read this article on chimps doing memory experiments - and beating the humans!

Then go back to YouTube and watch Mel Smith & Rowan Atkinson do "The Gerald the Gorilla Sketch"

Baffled by the whole Skinner versus Chomsky debate on learning language? Read a short extract by Bill Bryson making the whole thing plain as day.

Background and context

The psychology of language is a bit of a battefield between two opposing points of view. On the one hand, Behaviourists think that language is just a learned skill, rather like learning your times table or riding a bike. If animals are reasonably clever and have social instincts (like apes) then they ought to be able to learn language too. On the other hand, Nativists argue that human beings seem to have a special language instinct that other animals lack. They would arge that you can train animals to do tricks that look like language, but the animals don't really understand what they're doing.

Previous research has not settled this argument. In the 1960s, husband-and-wife team Allen and Trixie Gardner adopted a year-old chimpanzee called Washoe and moved her into a caravan in their garden. They spent two years teaching her American Sign Language (ASL). Washoe learned an impressive number of signs and the Gardners were convinced she was using language to communicate with them. Critics pointed out that Washoe had been trained to use signs (she was rewarded wth treats and tickles), that she never learned to use syntax (varying the order of signs to change their meaning) and that the Garders were probably guilty of ANTHROPOMORPHISM - reading human qualities into animals when really those qualities aren't there.

The problem is there's more to language than just responding when someone says something. After all, a dog can respond when you say "Sit!" but that doesn't prove it understands English. The important point about children is that they learn languge spontaneously - no one has to train them the way you train dogs.

Aims

Having spent her career working with apes, Sue Savage-Rumbaugh hopes to settle the language debate and show that pygmy chimpanzees have human language capabilities.

In order to demonstrate this, the apes need to show language-use spontaneously (without being trained) and should demonstrate STRUCTURE DEPENDENCE or syntax - putting symbols into a special order to convey different meanings.

The sample

This is a case study and the main subject was a bonobo ape (pygmy chimpanzee) named Kanzi. Bonobos are smaller than common chipanzees, more sociable (they share food) and seem to be brighter. The researchers compared Kanzi (age 3) and his sister Mulika (age 1) with  a pair of common chipanzees named Austin and Sherman. These two chimps had been trained to use symbols the regular way, with rewards.

Kanzi used to go with his mother to her language classes. He was never "taught" any symbols but he started to use them spontaneously when his mother went away on a breeding programme. Presumably he saw his mother using symbols and copied her, because when Kanzi's sister was born she started using symbols that she had learned from her big brother! 

Procedure

Apes cannot talk (they don't have vocal chords) but they have a lot of skill with gestures. Savage-Rumbaugh designed a board containing dozens of LEXIGRAMS. These were brightly coloured squares that represented pastimes ("chase"), food ("strawberry"), people and places - there's a picture on the right. The apes learned to point to certain lexigrams to communicate their wishes. Humans would act as role models around the apes when talking to each other by pointing to the lexigrams for the words they were using.

There were two versions of the lexigram board. Indoors there was an electronic board connected to a computer. When a lexigram was pressed it lit up, the computer recorded it and an electronic voice would speak the word out loud. Outdoors there was a tough laminated board and observers would record which lexigrams the apes pointed to and enter the data into the computer later. Every utterance was classed as correct or incorrect, but also as spontaneous, imitated or structured: imitated utterances repeated back symbols a human had used while structured utterances used symbols in reply to a request or a question.

The apes lived in a 55 acre wooded park with 17 named locations where different types of food were placed. To get food, the apes had to go to these locations. At first Kanzi was shown photographs of different food and taken to the location of the food he chose. Within 4 months Kanzi could select a photo and guide others to the right place (often carrying Mulika!). Later, he and Mulika could use the lexigrams to choose their own meals and journeys.

Tests and measures

Before a symbol counted as part of Kanzi's language, it had to be verified on 9 out of 10 occasions. If Kanzi indicated he wanted to go to the treehouse then took the experimenter to the treehouse, this counted as POSITIVE CONCORDANCE - proof that Kanzi was acquiring the symbol for "treehouse".

The reliability of the observations had to be tested, so 4½ hours of observations were videoed and another observer watched the tape. There was 100% agreement on the correctness of the lexigrams and one disagreement about spontaneity.

Sometimes the lexigrams were moved to new positions, but the apes had no problem identifying them. At the end of the 17 month study, Kanzi was tested on his knowledge of lexigrams. Kanzi was either shown a photograph or listened to a word, then had to identify the right lexigram.

Outcomes

When young, Kanzi started using the "chase" lexigram to get humans to play with him and spontaneously invented a gesture (hand clapping) with the same meaning. Kanzi and Mulika both invented gestures (eg to tell humans to blow up balloons for them) and these gestures were clearer and more explicit than those used by the chimpanzees Sherman and Austin.

Kanzi started using lexigrams when his mother went away (when he was 2½) and Mulika began using lexigrams properly at 14 months. The apes used symbols through association first. For example, since Kanzi was introduced to strawberries at the mushroom site, for a while he used the "mushroom" lexigram for strawberries. Human children use similar associations when learning words. The apes were like children also becuse they imitated more often when learning new words - about 15% of their utterances were imitated and 80% were spontaneous and this is about the same for human children. By the end of the study, Kanzi had acquired 46 words and Mulika 37.

Kanzi went on to combine symbols together. Over the 17 months, Kanzi produced 2540 non-imitated combinations, along with 265 that were prompted or partly imitated: all but 10 were judged by observers to be appropriate and comprehensible. In the formal tests the bonobo apes did well and had no problem understanding spoken words, even from the voice synthesizer machine (which the researchers had difficulty understanding!). The chimpanzees Austin and Sherman did less well, because when they identified an object (eg "banana") they expected to be given it as a reward.

Sometimes Kanzi took the lexigram board off by himself, as if he wanted to practise with it. Kanzi was also introduced a a visitor who had never been to the woods before (and therefore couldn't provide any cues). Kanzi was able to identify a photo or lexigram and guide the "blind" visitor to the right place. Kanzi could also guide the visitor to locations identified by spoken English rather than symbols.

Conclusions

Although Kanzi produced fewer combinations than other language chimps in previous studies, his three-symbol phrases never referred to himself, whereas the famous Nim Chimpsky who produced 19,000 combinations would often say things like "more eat Nim". Most chimps use language about food, whereas Kanzi mostly referred to games (eg "chase bit person").

Pygmy chimpanzees like Kanzi and Mulika seem to have a natural talent for using symbols - they were better at it than the common chimpanzees, learning the lexigrams faster and without needing training, understanding spoken English without being trained and using the lexigrams to refer to specific things (eg "juice" or "coke") whereas Sherman and Austin would use symbols interchangeably ("eg "juice" or "coke" for any drink).

Most importantly, Kanzi could use language to direct other people to do things (eg request a human to chase another chimp). Sue Savage-Rumbaugh regards this as the beginnings of syntax, because word order makes it clear who is intended to do what to who. An example of this is when Kanzi was playing with his toys (a plastic dog and snake) Sue Savage-Rumbaugh used the lexigrams to make the computer say, "Make the dog bite the snake". Kanzi put the snake into the dog's mouth and pressed its jaws together. If Kanzi hadn't understood word order, he might have made the snake bite the dog instead.

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