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Language in Primates • Do our closest evolutionary relatives have the ability to learn and use language? • If so, then the differences between our respective species may be less than we have previously believed. • Chimpanzees (Washoe, Loulis, Nim) • Bonobos (Kanzi and Matata) • Gorillas (Koko)
Chimps: Washoe • Adopted by Drs. Beatrix and Allen Gardner • Studied by Drs. Roger & Deborah Fouts since 1980 • First chimp to be taught ASL • Was able to learn about 200 signs and combine them 2 or 3 at a time • Taught signs to her adopted son Loulis
Chimps: Nim Chimpsky • Taught ASL by Herbert Terrace. • Skeptical of reports about Washoe • Was able to teach Nim numerous signs • Never saw evidence that Nim could combine signs except when promted to do so by experimenters • Nim died last year
Bonobos: Kanzi • Studied by Dr. Sue Savage-Rumbaugh • Was present when his mother (Matata) was being taught to use lexigrams • Though Matata didn’t learn, Kanzi did • Spontaneously learned and combined many lexigrams • Shows evidence for comprehending word order
Bonobos: Is Kanzi typical? • In a word, no. • Though other bonobos have learned some lexigrams, only one other has done so to the degree of Kanzi. (His mother learned 6 lexigrams in 5 years, his sibling learned about 15 in 3 years). • Was it because Kanzi is somehow unique, or were the conditions of his rearing unique? • Probably the latter. Learned the symbols through natural exposure rather than rigid training. • Best evidence for language acuqisition in non-humans to this date
Gorillas: Koko • Dr. Francine Patterson taught Koko ASL • Knows several hundred signs and combines them • Uses signs for emotion (e.g. Sad kitten gone) • Chats on the internet (no, really)
Would Koko like to have a kitten, a dog, or another Gorilla as a friend? • LiveKOKO:dog • DrPPatrsn:She actually has two dog friends right now one kitty and two gorillas. • HaloMyBaby:SBM87 asks, What are the names of your kittens? (and dogs?) • LiveKOKO:foot • DrPPatrsn:Foot isn't the name of your kitty • HaloMyBaby:Koko, what's the name of your cat? • LiveKOKO:no • Koko tell us what you look like in your words? • LiveKOKO:flower • DrPPatrsn:One of the scrunchies has a big flower on it. • LiveKOKO:eat now • DrPPatrsn:She wants some more of the snack, apparently. • LiveKOKO:sleep, red red • DrPPatrsn:She's indicating the red scrunchie.
How about computers? • Many attempts to get computational systems to learn language a la the child • Most have used some sort of connectionist, or parallel distributed processing, network to accomplish this feat (artificial neural networks) • Try to model various aspects of language acquisition • Vocabulary learning (Elman) • Acquisition of the past tense (Rumelhart & McClelland)
Rumelhart & McClelland (1986, 1996) • Past-tense learning • Works on phonological pattern recognition and prior experience with regular and irregular verbs • Attempts to generalize rules and apply them to novel stems the system has never encountered before (just like a child)
How does it do? • Correctly generalizes to about 70% of unfamiliar word stems • Makes many errors of types that children never make • mailmembled • winkwok • satisfysedderded • smairfsprurice • frilgfreezled • smeejleefloag
What to conclude • Pinker and others take these sorts of results as proof that a general AI learning system could not learn language • Others see these as good approximations of what actually occurs, and simply that the model and/or parameters and/or the input needs to be specified differently • Will we ever have a language learning machine? • Nick Lacey’s gonna tell us