Teaching Sign Language to a Chimpanzee

8/18/2019 Teaching Sign Language to a Chimpanzee

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Gardner & Gardner (1969)


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1. How do animals communicate?2. What is so special about human language?

3. Early attempts

4. Gardner & Gardner5. Evaluation

6. Subsequent studies

7. Further criticisms

8. Latest developments


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Bird songs Bee dance Whale songs Primate vocal calls

Used in certain contexts: mating, danger of predation etc Associated with basic brain structures


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Chomsky (1959)

Structured and governed by principles Used in a specific manner Governed by special language centres

Pinker (1994)

Infinite Digital Compositional

Aitchison (1983) identifies 4 characteristics which are unique tohuman language

Semanticity Displacement Creativity Structure-dependence


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Teaching vocal language to chimpanzees, adoptedand raised in families (cross-fostering)

Kellog Kellog (1933)

Gua (chimpanzee)- never produced any single word andseemed to understand only a few

Hayes Hayes (1951)

Viki (chimpanzee)- mama, papa, cup, up.

Chimpanzee’s vocal apparatus not suited for speech.


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Design

Case study of an enculturated infant female chimp, WashoePhase one: extending over 22 monthsASL training (pictorial sign language, with grammar and

syntax)

Training by operant conditioning (positive reinforcementmainly)


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Scoring

When Washoe learned a new sign, it was onlyafter three different observers noted it ashaving occurred in an appropriate context

and spontaneously, the sign was added to a“checklist”

A reported frequency of at least 1 appropriate

and spontaneous occurrence each day over aperiod of 15 consecutive days was taken asthe criterion of acquisition


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Outcome

Within 22 months of training, Washoe learned 30signs and used them reliably Come-gimme, more, up, hurry, toothbrush … Hurt, sorry, funny …

Rate of vocabulary acquisition was accelerating Spontaneous transfer (e.g. flower for various

smells) Used rudimentary combinations of signs,

apparently also novel ones (e.g. gimme tickle,listen dog )

Trained her adopted son, Loulis, in ASL


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Strengths

Decision to teach ASL- breakthrough

Very intensive training schedule, using simple

operant conditioning Care for the welfare of the animal

Multiple observers, standard criteria for judging whether Washoe learned a new sign

or not Long-term study, extended to include

Washoe’s adopted children


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Crucial question:

s it language or not

Semanticity? Creativity? Displacement? Structure-dependence?

Can you explain the acquisition of „ape language” byother means?

Note that: In humans, babies are not explicitly taught by their parents

to speak, yet within a few years of life they master languagecompletely

Chimpanzees don’t develop language in nature


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Premack (1971)

Sarah, communication with small plastic symbols

no claims for proper language

Patterson (1978, 1980)

Koko (gorilla), taught ASL; allegedly quitesophisticated language

„Language is no longer a uniquely human faculty”


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Terrace (1979)

Nim Chimpsky, taught ASL; rigorous methodology Initially reported success

Upon evaluation, concluded that what Nim learnedwas not language No grasp of grammar

MLU constant

Imitative in nature

No „conversation”

A fierce critic of ape-language research


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Noam Chomsky

In humans, language cannot possibly belearned through operant conditioning.

LAD

Steven Pinker

Signs or gestures? Problems with interpretation

Average length of utterrance Usage


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Savage-Rumbaugh

Kanzi, a bonobo chimp

Lexigrams

Learned language via observation, notdeliberate training

Focus on understanding

Rudimentary grammar

Invents some protogrammatical rules Language ability of a 2.5-year-old child


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If chimpanzees cannot learn language

Why is that? What specific prerequisite dothey lack? Innate language module?

Theory of Mind?

Perhaps training methods were inadequate

Perhaps chimpanzees need a longer time toacquire language


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If chimpanzees can learn language

Then language is not a uniquely human capacityanymore

The difference between animals and humansmust be redefined

Research on ToM in primates needs to bereconsidered

The evolution of language must be rewritten Language evolved long time ago, in an ancestor common to

chimps and humans? But why wouldn’t chimpanzees use language in

the wild?


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Key reading

Gardner, R.A. & Gardner, B.T. (1969). Teaching sign language to achimpanzee. Science, 165, 664-72.

Additional readings

Gibbons, A. (1991). Deja vu all over again: chimp-language wars. Science,251, 1561-1562.

Terrace, H.S., Pettito, L.A., Sanders, R.J. & Bever, T.G. (1979). Can an apecreate a sentence? Science, 206, 891-902.

Washoe „Obituary” in the New York Timeshttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087%0A&oref=slogin

ASL video dictionaryhttp://commtechlab.msu.edu/sites/aslweb/browser.htm

I just couldn’t resits… A very non-scientific demonstration of the limits ofhow much we can attribute to primates:http://www.youtube.com/watch?v=qiiUrAS9BL4
http://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=sloginhttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=sloginhttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=sloginhttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=sloginhttp://commtechlab.msu.edu/sites/aslweb/browser.htmhttp://commtechlab.msu.edu/sites/aslweb/browser.htmhttp://www.youtube.com/watch?v=qiiUrAS9BL4http://www.youtube.com/watch?v=qiiUrAS9BL4http://www.youtube.com/watch?v=qiiUrAS9BL4http://commtechlab.msu.edu/sites/aslweb/browser.htmhttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=sloginhttp://www.nytimes.com/2007/11/01/science/01chimp.html?_r=1&em&ex=1194148800&en=953723ba97c73b53&ei=5087&oref=slogin

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Teaching Sign Language to a Chimpanzee