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 Done Part II: Give you an appreciation for the big picture  Why it is a grand challenge What are we trying to do How do we do it A lot of people would start with the history – but it’s a bit meaningless at first

Done Course Overview Step back and look at the Science 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 Done Part II: Give you an appreciation for the big picture  Why it is a grand challenge What are we trying to do How do we do it A lot of people would start with the history – but it’s a bit meaningless at first

Course Overview Looking at the Science 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 What are we trying to do How do we do it A lot of people would start with the history – but it’s a bit meaningless at first

Course Overview Looking at the Science 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 What are we trying to do How do we do it A lot of people would start with the history – but it’s a bit meaningless at first

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 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: Patterns in grammar of natural language cannot be learned using positive evidence alone Children are only ever presented with positive evidence 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

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 Sign language 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

Part 2: On a higher level of concepts and thinking, what does language tell us about what is going on inside?

Sapir-Whorf Hypothesis Language's nature influences the habitual thought of its speakers. Hopi language Western languages : the present and future are thought of as "places“ Time is a path linking them "three days" equivalent to "three apples", or "three kilometres“ Native American languages oriented towards process Inuit people Numerous words for snow Modifies the world view of the Eskimo Creates a different mode of existence for them Geoffrey Pullum: "The great Eskimo vocabulary hoax“ Language of the Pirahã tribe of Brazil Contains three counting words: one, two and many. Pirahã people have difficulty recounting numbers > 3 Controversy: maybe Pirahã have no need to practice doing so

Sapir-Whorf Hypothesis Strong form of hypothesis: language determines thought Popular in fiction: Orwell’s 1984 newspeak, e.g. no freedom Generally not accepted nowadays But some weaker elements may be present Different languages categorise the world in different ways In English: The dog ran through the forest The dog ran through the table(!) In English the table is more thought of as its top Other languages think of it more as its legs

Classifiers and Categories George Lakoff book: Women, Fire and Dangerous Things Dyirbal language I - most animate objects, men II - women, water, fire, violence, and exceptional animals III - edible fruit and vegetables IV - miscellaneous (everything else)

Metaphors Argument is war Your claims are indefensible He attacked every weak point in my argument His criticisms were right on target I demolished his argument I’ve never won an argument with him You disagree? Okay, shoot. If you use that strategy he’ll wipe you out. He shot down all of my arguments.

Metaphors Time is a resource You’re wasting my time This gadget will save you hours I don’t have the time to give you How do you spend your time these days? That flat tire cost me an hour I’ve invested a lot of time in her I don’t have enough time to spare for that You’re running out of time Do you have much time left? He’s living on borrowed time Thank you for your time I lost a lot of time when I got sick

Metaphors The conduit metaphor Examples Ideas are objects Language expressions are containers Communication is sending Examples It’s hard to get that idea across to him I gave you that idea Your reasons came through to us It’s difficult to put my ideas into words His words carry little meaning Your words are hollow The idea is buried in terribly dense paragraphs

Metaphors Up is positive, down is negative He is at the peak of health He came down with flu His health is declining I am on top of the situation He is at the height of his power His power rose He fell from power The stock is rising We are at an all-time low

Metaphors Personification …inflation is an adversary Life has cheated me His religion tells him he cannot drink wine The Michelson-Morley experiment gave birth to a new physical theory Cancer finally caught up with him Inflation has attacked the foundations of our economy Inflation is eating up our profits Inflation has robbed me of my savings Inflation has outwitted the best economic minds in the country …inflation is an adversary Declare war on inflation Call for sacrifices Install a new chain of command

Metaphors Lakoff’s Thesis: cognition is depends on the linguistic metaphor We are completely immersed in metaphors There seems to be no way to say some things without metaphors