Savage-Rumbaugh et al. (1986) Spontaneous symbol acquisition and communicative use

1. Savage-Rumbaugh et al. (1986) Spontaneous symbol acquisition and communicative use by pygmy chimpanzees (Pan paniscus)

2. Savage-Rumbaugh et al. (1986) • Aim: • To report on the language acquisition of Kanzi, a bonobo, and his younger sister Mulika. • The report covers a 17-month period, beginning when Kanzi was aged 2½ years. • To compare language acquisition in the bonobos with that of two common chimpanzees, Sherman and Austin, studied earlier (1975-1980). Sherman & Austin – common chimps (Pan troglodytes) Kanzi – a bonobo chimp (Pan paniscus)

3. Savage-Rumbaugh et al. (1986) • Method: • A CASE STUDY was carried out, focusing on one bonobo, Kanzi, but also including early data of his younger sister Mulika’s language acquisition. • Data were gathered by OBSERVATION and SELF-REPORT (computer) • The design was LONGITUDINAL, reporting over a 17-month period of Kanzi’s language acquisition. • Think! • What are the potential STRENGTHS and WEAKNESSES of the method chosen? • Can findings from a case study be generalised? • - Are findings gained from observation reliable and valid? • - Can all variables be controlled in a longitudinal study?

4. Savage-Rumbaugh et al. (1986) Kanzi – born in captivity in US (1980) Subjects: His mother was Matata, a wild- captured bonobo, who was the actual intended subject for the language study Matata was not Kanzi’s biological mother. She had kidnapped him from his mother, Lorel, when he was just a few hours old In 1983, Matata gave birth to Mulika, the second bonobo subject in this research She grew up as Kanzi’s sister

5. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 1. Description of the environment where the apes were living Naturalistic outdoor environment Indoor environment • In the day, Kanzi and Mulika helped with domestic chores e.g. food preparation • Helped spontaneously with simple jobs like washing up • Watched videos of people/animals they knew from the centre • Played with toys • Played games e.g. tickle, chase… • 55 acre forest • Food placed in 17 locations – Kanzi + carers spent most of day collecting it • Kanzi communicated about food in the forest, and in a backpack, with lexigrams • Mulika also did this as she got older

6. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 2. The communication system used with the apes The lexigram system: • A visual symbol system • A keyboard of symbols, lit up when pressed • To start with Kanzi’s board had 8 lexigrams • By the end of the study, had 256 lexigrams • Connected to an electronic voice synthesiser – Kanzi understood spoken English • Indoors, the keyboards weren’t mobile – attached to computer • Outdoors, Kanzi used portable keyboards and laminated pointing boards • Other means of communication: • Spoken English • Gestures, including 100 ASL gestures

7. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 3. The exposure of Kanzi and Mulika to lexigrams – how they learned • Kansi was exposed to use of symbols, gestures, and human speech from age 6 months • This happened as he watched his mother, Matala, and her keepers • No-one tried to train Kanzi directly • Mulika learned from observing Kanzi The lexigram system • They used the same lexigram system as Sherman and Austin • However, Sherman and Austin were taught to use it – Kanzi and Mulika weren’t. They spontaneously used it after observing others • Other differences between Kanzi and Mulika, and Sherman and Austin: • On Sherman and Austin’s keyboards there was no voice synthesiser – they didn’t understand human speech • Sherman and Austin didn’t use lexigrams outdoors – they couldn’t use them if they didn’t light up

8. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 4. Data recording and classifying Recording: • INDOORS – lexigram use could be automatically recorded • OUTDOORS – a record was made by hand and entered into computer later • There was a complete record of Kanzi’s utterances from 30-47 months of age • For Mulika, the record ran from 11-21 months Classifying the utterances: • The utterances were classified as: • ‘correct’ or ‘incorrect’ • ‘spontaneous’ if there was no prompting or cueing • ‘imitated’ if they included a companion’s utterance • ‘structured’ if they were in response to a question • Structured questions were used to see if the chimps • could give a specific answer

9. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 5. Vocabulary acquisition criteria What counted as ‘acquired’? • Utterance happened spontaneously, and could be verified on 9 out of 10 times • e.g. if Kanzi indicated he wanted to go to the treehouse it would be verified if he took the experimenter to this location. This was counted as a ‘positive concordance score’ Establishing reliability: • A 4½-hour block of real-time observations were • compared with analysis of a video made at the same • time. • There was 100% agreement on the lexigrams used and their correctness • There was disagreement on whether one utterance was spontaneous • The video observer counted 9 extra utterances

10. Savage-Rumbaugh et al. (1986) Procedure: The procedure is in 6 parts 6. Formal testing of productive and receptive capacities When? • At the end of the study, Kanzi and Mulika were formally tested on all the words in their vocabulary. • Kanzi was tested in the 17th month of the study, aged 46-47 months • Mulika was tested aged 18-21 months Why? • To ensure that their performance was not due to the experimenters giving them cues, or inadvertent glances. How? • They were shown photographs and asked to select the right lexigram (+ vice versa) • They listened to a word or a synthesised version of the word and then asked to select the correct photograph or lexigram