Course Overview  What is AI?  What are the Major Challenges?  What are the Main Techniques?  Where are we failing, and why?  Step back and look at the Science  Step back and look at the History of AI  What are the Major Schools of Thought?  What of the Future? Part I: Introduce you to what’s happening in Artificial Intelligence Part II: Give you an appreciation for the big picture  Why it is a grand challenge Done

Course Overview  What is AI?  What are the Major Challenges?  What are the Main Techniques?  Where are we failing, and why?  Step back and look at the Science  Step back and look at the History of AI  What are the Major Schools of Thought?  What of the Future? Part I: Introduce you to what’s happening in Artificial Intelligence Part II: Give you an appreciation for the big picture  Why it is a grand challenge Done

Course Overview  What is AI?  What are the Major Challenges?  What are the Main Techniques?  Where are we failing, and why?  Step back and look at the Science  Step back and look at the History of AI  What are the Major Schools of Thought?  What of the Future? Looking at the Science  Engineering vs. Science  Introduction to Cognitive Science  Cognitive Psychology 1  Cognitive Psychology 2  Cognitive Development  Linguistics  Neuroscience  Philosophy

Course Overview  What is AI?  What are the Major Challenges?  What are the Main Techniques?  Where are we failing, and why?  Step back and look at the Science  Step back and look at the History of AI  What are the Major Schools of Thought?  What of the Future? Looking at the Science  Engineering vs. Science  Introduction to Cognitive Science  Cognitive Psychology 1  Cognitive Psychology 2  Cognitive Development  Linguistics  Neuroscience  Philosophy

Linguistics in Cognitive Science  Why are Cognitive Scientists Interested in Linguistics?  Language seems to be uniquely human trait  All normal humans use language  Animals don’t seem to –Sometimes have some signals, but no complex grammar, relationships –Not sure about dolphins…  Language is how we express our thoughts  It must give us some hints about those thoughts themselves  Language is easy to study  Compare with brain scans, or anthropology

Linguistics in Cognitive Science  Example: Grammar  Grammar is the study of the rules governing the use of a given natural language  Why is that interesting?  Trying to get some scientific hypothesis about the language knowledge native speakers have  How to describe that knowledge?  The dog irritated Mary.  Mary irritated the dog.  Dog the Mary irritated.  Irritated the Mary dog.  Describe grammar as a list of options?  It seems we would have to describe too many options  These rules seem to be best described by algorithms  Quite advanced - recursion  Quite complicated  Note: these are used by ALL speakers, not just some advanced experts

Knowledge of Grammar is Implicit  We all know the rules…  but are usually unaware of this knowledge  The rules of a natural language are very complicated  Hard to find because they are implicit  More complicated than grammar you might learn in school  John believed that pigs can fly.  That sugar is sweet is obvious to everyone. (optional that)  The pain that I feel is unpleasant.  The dog that bit me is missing now. (seems to depend on head-subject)  Everybody knows the rules, but few can write them down  These rules are complicated…  but most kids have learnt most by 5 yrs … how?  Language acquisition – address later

Overview of Linguistics Areas  Phonology - sounds  Lexical - words  Morphology - words built up of bits  Syntax – order of words  Semantics - meaning  Words  Sentences  Pragmatics  Pretty much everything else  Example: Context  Example: Gricean maxims  Example: Dialogues

Morphology  Two types of languages:  Synthetic: stick parts together to make words  English has synthetic features: Unbreakable, Antidisestablishmentarianism  Turkish: Avustralyalılaştıramadıklarımızdanmışsınız  Analytic: order of words is used to make up the meaning  Chinese, many far-eastern languages  Example: tense is indicated by words around, rather than conjugation  Morphemes are smallest bits of language that have meaning  Example: cat, dog, happy, un-, -ness, -s, break, -able, -ory, -ment  Many ways to things  Can compound words: toothbrush  Output of one can input to another  Toothbrush-holder  Unmicrowaveability  Can use recursion  Anti-missile missile  Anti-anti-missile missile missile  Anti-anti-anti-missile missile missile missile  Need to keep track of antis and missiles

Phonology  Phonology tells us how words (made of morphemes) get pronounced  Examples…  Plural: cat  cats  Plural: dog  dogs  Pronounced “dogz” … why?  Plural: glass  glasses  What about non-words  Blort  ?  Blorb  ?  Blorch  ?  There seem to be some rules being applied

Phonology  Example: Do you want to?  Do you wanto  Do you wanna  Dyu wanna  Juwanna  Is this simply what happens when you try to force your voice to go fast  Or are there also rules?  Another example  I’m going to leave (“to” is part of the verb)  I’m gonna leave  I’m going to New York (“to” is a preposition)  I’m gonna New York (sounds odd?)  I’m going to split  I’m going to Split (city in Croatia)  I’m gonna split  Depends on grammar rules…  Interestingly… principles of phonology also apply to sign language  Something common underlying both grammars

Syntax Noam Chomsky  “A Review of BF Skinner's Verbal Behaviour”  Challenged the behaviourist approach (was dominant in the 1950s)  Especially to the study of language  Sparked the “cognitive revolution” in psychology  Mind contains mental states, beliefs, desires, intentions  Most properties of language and mind are innate (puts him at odds with Piaget)

Poverty of the stimulus  Premises: 1.Patterns in grammar of natural language cannot be learned using positive evidence alone 2.Children are only ever presented with positive evidence 3.Children do learn the correct grammars for their native languages  Conclusion  Humans must have some innate knowledge of the rules for language  Example of what is learned:  Statement: You are happy.  Question: Are you happy?  Statement: Anyone who is interested can see me later. 1. Is anyone who interested can see me later? 2. Can anyone who is interested see me later?  Some controversy… some premises not accepted by some  Example: Maybe domain general learning theory adequate  Example: Some say positive evidence is enough

Universal Grammar  A basic grammatical structure common to all human languages  Humans are born with innate knowledge of this Principles and Parameters approach  Grammatical principles underlying languages are innate and fixed  Differences among world's languages are parameter settings in the brain  Example: “pro-drop parameter”  Indicates if an explicit subject is always required  Yes in English  No in Spanish, Maltese  Mar. Maltese sentence "he went/left" (verb)  A child learning a language only needs to  acquire lexical items (words, grammatical morphemes, and idioms)  and determine the appropriate parameter settings  can be done based on a few key examples

Universal Grammar  Principles and Parameters approach Explains a lot…  Rate at which children learn languages is very fast  Similar learning steps taken by children across the world  Children make same characteristic errors on first language  Some seemingly logical kinds of errors never occur

Some Limitations on Internal Buffers…  “That many teachers are being laid off in a shortsighted attempt to balance this year’s budget at the same time that governor's cronies and bureaucratic hacks are lining their pockets is appalling.”  “It is appalling that many teachers are being laid off in a shortsighted attempt to balance this year’s budget at the same time that governor's cronies and bureaucratic hacks are lining their pockets.”  Maybe grammar allows choice to ease buffer burden  “The rapidity that the motion has is remarkable.”  “The motion that the wing has is remarkable.”  “The rapidity that the motion that the wing has has is remarkable.”  “The rapidity that the motion that the wing that the hummingbird has has has is remarkable.”  “The dog bit the cat.”  “The dog the stick beat bit the cat.”  “The dog the stick the fire burned beat bit the cat.”  Not short term memory… seems to be one part of the “parser”  Special buffer for this type of “incomplete phrase” – buffer size = 1!

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks …

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat …

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat accumulates.”

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat accumulates.”  “The cotton clothing is usually made of …

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat accumulates.”  “The cotton clothing is usually made of grows in Mississippi.”

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat accumulates.”  “The cotton clothing is usually made of grows in Mississippi.”  “The horse raced past the barn …

Ambiguity and Garden Paths…  “Rumour had it that, for years, the government building had been plagued with problems. The man was not surprised when he found several spiders, roaches, and other bugs in the corner of his room.”  Human must make choices… how long to entertain alternatives?  “The man who hunts ducks out on weekends.”  “Fat people eat accumulates.”  “The cotton clothing is usually made of grows in Mississippi.”  “The horse raced past the barn fell.”  Conscious processing of grammar is necessary for difficult writing.

Language Acquisition  Children learn very quickly  17 year old has about 60,000 words  Must learn about 10 new words a day  6 year old has about 13,000 words  Child learns a new word every two hours  Learning a word is not easy  Know what aspect of situation was referred to  Without having to try the word in many situations  Example: gavagai  Humans tend to chop up the world into the same categories

Language Acquisition Do children have a special device for language learning?  Children learn very quickly and easily  Children become perfect speakers  adults usually learn second language imperfectly  and with great difficulty  Children make mistakes, but not the same ones adults make  Example: Children never misjudge appropriate position of question words  Even on basis of sentences like "I know what John ate."

Language Acquisition  Hawaiian sugar plantations  Adults from many countries  Communicated in pidgin  Their children invented a creole  Some controversy about the claims  Sign language  Nicaragua created new schools for the deaf  Younger children invented a new sign language

Course Overview  What is AI?  What are the Major Challenges?  What are the Main Techniques?  Where are we failing, and why?  Step back and look at the Science  Step back and look at the History of AI  What are the Major Schools of Thought?  What of the Future? Looking at the Science  Engineering vs. Science  Introduction to Cognitive Science  Cognitive Psychology 1  Cognitive Psychology 2  Cognitive Development  Linguistics  Neuroscience  Philosophy