Savage-Rumbaugh, S., MacDonald, K., Sevcik, R. A., Hopkins, W. D. and Rubert, E. (1986) Spontaneous symbol acquisition and communication use by pygmy chimpanzees (Pan paniscus)
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.
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.
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.
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
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.