Savage-Rumbaugh 1986

Savage-Rumbaugh 1986

1. Background

   • Associative symbol learning occurs when an individual learns to associate specific symbols with specific objects, for example naming pictures in a book.
   • It has been demonstrated that a more sophisticated type of learning can appear when chimps are systematically taught how to request, label and comprehend objects.

2. Evaluation

   • Strengths
     • Longitudinal- allows in depth data to be collected about development over time. For example, utterances made by Kanzi was documented over a 17 month period.
     • Data was gathered under rigorous controls (e.g. the formal tests) and is therefore are less likely to be open to bias and subjectivity. This improves reliability and validity.
     • Triangulation- Both qualitative and quantitative data was gathered which improves the richness of the study and allows for analysis and comparison.
   • Weaknesses
     • Ecological validity is low as the subjects were not reared in their natural environment.
     • Ethical issues- it could be considered unethical and unnecessary to remove chimpanzees from the wild and study them in a human environment and to test their language skills in a formal way.

3. Results/Findings

   • Kanzi and Mulika spontaneously began to use gestures to communicate between 6-16 months, it took Sherman and Austin between 2-4yrs.
   • Kanzi and Mulika’s gestures were more explicit than Austin and Sherman's.
   • Kanzi and Mulika did well on formal tests from the beginning - Austin and Sherman became confused, so they had to slow down the process.
   • Kanzi and Mulika had a better understanding of spoken language, used the lexigram spontaneously and could distinguish between categories and refer to requests involving others.
   • Kanzi's recognition of symbols preceded his production of them for 63% of the words in his vocabulary. More than 80% of Kanzi's utterances were spontaneous, with only 11% being imitated or prompted.
   • Kanzi produced 2,540 combinations within 17 months, 764 of which were unique.
     • This was 6% of his total utterances. All of his three word utterances were to instruct someone else (eg Person tickle Kanzi).
     • 36% of the time it was initiated by Kanzi and not imitated.

4. Method

   • Aim: to investigate the language acquisition of two pygmy chimpanzees and two common chimpanzees.
   • Subjects
     • Principal subject: a male pygmy chimpanzee called Kanzi aged 30-47 months.
       • Kanzi was born in captivity and assigned at 6 months old with his mother (Matata), a wild caught chimp.
       • Studies suggest that they are a more social species with more developed social skills. This suggests that they may be more able to acquire language.
       • Mulika was Kanzi's younger sister, aged 11-21 months. Both Kanzi and Mulika spent several hours a day with their mother, but they appeared to prefer human company.
     • Two common chimpanzees were used for comparison: Austin and Sherman. They were assigned at 1.5 and 2.5 years of age. They were removed from their mothers before the study.
   • Longitudinal Quazi experiment
     • IV= Species (bonobo/common)
     • DV= Language Acquisition
   • Procedure
     • Utterances were recorded in three categories.
       • Spontaneous- without prompting.
       • Imitated- containing words from the researcher's utterance.
       • Structured- in response to a question/request.
       • Lexigram: a system of geometric symbols. Kanzi's was connected to a speech synthesiser which speaks the words when the symbols are touched.
         • Researchers also used ASL (American Sign Language) gestures to accompany the lexigrams. Approximately 100 ASL gestures were used by the experimenters. None of the experimenters were fluent in ASL.
     • Kanzi and Mulika were tested by 4 tests: Photograph to lexigram/ Spoken English to photograph/ Spoken English to lexigram /Synthesised speech to lexigram

5. Conclusions

   • Pygmy chimps can learn in a very similar way to humans but the language may not be uniquely human.
     • Similar to children: taught by parents and teachers/trainers. Observations- symbols and images from picture books, etc.
   • Showed that pygmy chimps have the ability to acquire symbol use to a greater extent than other species of apes.

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