S EL2211: Contexts . Lecture 9: History of Language Sciences. The last few lectures: Pulling out the focus wider and wider Started with brains and neurons and ended up with one of the biggest issues in philosophy of mind The next few lectures: Bring the focus back in
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SEL2211: Contexts Lecture 9: History of Language Sciences
The last few lectures: • Pulling out the focus wider and wider • Started with brains and neurons and ended up with one of the biggest issues in philosophy of mind The next few lectures: • Bring the focus back in • Use the general ideas developed so far to examine familiar issues in linguistics Today • The birth of generative linguistics • A direct outgrowth of the mind/body problem
Background, part 1Logical Positivism to Behaviorism The mind/body problem in the early 20th c. and the nature of science • Logical Positivism • Vienna, Austria – early 1920’s • Arises out of concern with 19th century (particularly German Romantic) metaphysics • “The absolute is beyond time.” • “Beauty is significant form.”
Logical Positivism • Their proposal: The Verifiability Principle of Meaning • a sentence is literally meaningless unless it could, at least in principle, be shown to be true or false by reference to actual, empirical observations (related to a more general philosophical position – empiricism – more on this in a sec) • Comes to be a huge influence on psychology (and social sciences in general) over next decades • Often slightly modified - a statement cannot be considered scientific if it doesn’t direct you to any observations or make predictions about things you could observe
In psychology, this leads to the behaviorist approach • No need to postulate anything unobservable in order to explain activities traditionally described as “mental” or “rational”. • Behavior of any organism in natural world need only be explained/described in terms of responses make to stimuli presented by features of the environment. J B Watson (1878 – 1958)
This is yet another response to the mind/body problem • It’s not that the mind is a computer, the whole thing is just hopeless. • “The mind” and “mental events” have no place in a properly scientific theory of human beings
Background, part 2Concepts and Terms from Behaviorist Psychology • The key question: what are the factors that shape behavior? • Empiricism: The only knowledge that you can get comes via the senses. There is no such thing as inborn or innate ideas or concepts or abilities. • Therefore, all behavior has to be the result of previous experiences – in particular, the associations between external stimuli (observable) and the organisms’ responses (also observable) • Hence the name: the association theory of learning
The prototypical association theory experiment (from http://www.simplypsychology.org/operant-conditioning.html)
The stimulus → response → reinforcement paradigm (in brief) • Rat is hungry (stimulus) • Bar press makes food pellet drop into cage (response) • When the rat is hungry, food pellet is a reward • Response of pressing bar when stimulus of being hungry occurs is reinforced • Whenever a stimulus-response pair leads to a reward (i.e. the hungry rat has its hunger satisfied), the association between the stimulus and the response is strengthened, and it becomes more likely that on subsequent occasions the same stimuli will result in the same responses.
A few other (sort of intuitive terms) • Secondary reinforcement • If a stimulus is strongly enough associated with a reward, the stimulus itself can become a reward (Chimps with plastic tokens that represent food). The stimulus is a secondary reinforcer • Extinction • when the rat/chimp/whatever responds in a certain way, and no reward is forthcoming, the response becomes less and less frequent. • The measure of how strong a connection is ( = how well something has been learned) is the rate of response under extinction
Skinner (1957) Verbal Behavior • Human verbal behavior is just like rats learning to press a bar, only a bit more complicated • Same basic set of variables: stimulus variables, response variables, and reinforcement variables • How do we predict (or control!) the occurrence of any given verbal response by understanding the stimulus and reinforcement variables B F Skinner (1904-1991)
An admittedly trivial example from George Miller • Person A: stimulus – book and another person; response – “hand me that book” • Person B: stimulus – book and A’s words; response – take book, approach A, say “here it is” • Person A: stimulus – B’s words; response – take book and say “Thank you” • Necessary stimulus-response associations need to be established beforehand, or the chain will be broken
If Person B is a monolingual Japanese speaker and does not associate the word “book” with the book on the table, then Person A’s verbal behavior wouldn’t have been reinforced in the past, and so might not happen. • If Person B knows that A is an ungrateful bastard, his response (giving the book to A when asked) wouldn’t have been reinforced in the past and so might not happen. • The job for the behaviorist psychologist/linguist: to describe all the factors that make one response (piece of verbal behavior) more probable than another, given that there are millions of possible things that one could say.
MandsvsTacts • Previous example = mand (request, command, etc.), but most verbal behavior is tacts (comments about the world, like “The apple is red”). • Why do people ever use these? • “Generalized” reinforcement • Money, social approval, etc. Can satisfy wide variety of needs • Tacts benefit the speaker indirectly via generalized reinforcement – “Mummy, the postman is here”
So, to recap • Human beings’ learning of linguistic behavior is just like rats learning to press a bar • It’s all stimulus – response – reinforcement conditioning • The task of the behaviorist linguist is to identify the variables that control verbal behavior and to specify how they interact in order to produce a particular verbal response. • (As a sideline, we can also learn how to manipulate the environmental stimuli in order to control people’s verbal behavior!)
Chomsky (1959) –Review of Verbal Behavior • Appeared in Language – the journal of the Linguistic Society of America • Basically destroyed behaviorism as a respectable framework for linguistic analysis • Why? How? • Systematically goes through every technical term in the behaviorist paradigm and shows that they couldn’t possibly explain human linguistic behavior • The ‘warlike’ tone
Here it is in a nutshell “[Skinner] utilizes the experimental results [from the laboratory] as evidence for the scientific character of his system of behavior, and analogic guesses (formulated in terms of a metaphoric extension of the technical vocabulary of the laboratory) as evidence for its scope. This creates the illusion of a rigorous scientific theory with a very broad scope, although in fact the terms used in the description of real-life and of laboratory behavior may be mere homonyms, with at most a vague similarity of meaning.”
In other words: • ‘stimulus’, ‘response’, ‘reinforcement’ etc. mean something and have sensible definitions when you’re talking about rats, but when you talk about verbal behavior in human beings, what has to count as a ‘stimulus’ or a ‘response’ ends up being incredibly vague, and has no relation to what ‘stimulus’ meant in the laboratory.
Problems with ‘stimulus’ • Let’s say you’re at a friend’s house and see this: • In the presence of the stimulus, you might responed “Dutch”. • So, for Skinner, your response is under the stimulus control of the painting’s “Dutchness”
But the (kind of obvious) problem is that you could have said anything • ‘I thought you liked abstracts.’ • ‘Man I hated that effing movie.’ • ‘Remember our camping trip last summer?’ • What Skinner has to say is that, for each of these responses, they’re under the control of a different stimulus property of the physical object (in this case, the picture). • As Chomsky notes, the device is as simple as it is empty.
More to the point, the term stimulus has lost all semblance of objectivity • We don’t know what the controlling stimulus is until we hear the response (making prediction impossible, btw) • And it just gets worse the more you look at it • ‘a needle in a haystack’ - controlled as a unit by a particular situation • ‘-ed’ controlled by ‘action in the past’ stimulus • An envoy reporting back on events observed in a foreign country is ‘under remote stimulus control’
There is no notion stimulus control that is even remotely related to the bar-pressing experiment which could cover all of these examples. In certain cases the organism need not even notice or be present when the controlling stimulus happens.
Problems with ‘response strength’ • For standard cases, this is the rate of response during extinction • If the rat hasn’t really learned that pressing the bar equals food, he won’t press it much more than usual after you stop dispensing food. But if the rat has really has learned that bar = food, then it’s more probable that he’ll keep on trying to press the bar for a while even. • Skinner says response strength for linguistic behavior = stress (energy level), pitch level, speed and delay of emission, and over-all frequency, among others • Skinner - if you are shown a prized work of art and you exclaim “beautiful”, the speed and energy of the response will not be lost on the owner
However, Chomsky sez, not clear that response strength as defined here has anything to do with communication • “it does not appear totally obvious that in this case the way to impress the owner is to shriek ‘beautiful’ in a loud, high-pitched voice, repeatedly and with no delay”. • you could indicate your pleasure with a response that has by definition a very low response strength: looking at the picture silently (a long delay in response), then murmuring ‘beautiful’ in a soft, low-pitched voice.
Problems with ‘reinforcement’ • Basically the same deal as ‘stimulus’ • In order to say that a behavior is ‘reinforced’, so many things have to count as ‘reinforcement’ that it becomes totally empty. • To reinforce verbal behavior, you can • Produce verbal behavior (say “thank you”) • NOT produce verbal behavior (sit quietly and pay attention) • Perform some action in the future • ‘Automatic self-reinforcement’ (e.g., babbling)
Chomsky: “Any idea that [the use of the word ‘reinforcement’] introduces any new clarity or objectivity…is a serious delusion....A mere terminological revision, in which a term borrowed from the laboratory is used with the full vagueness of the ordinary vocabulary, is of no conceivable interest….[It] is just a kind of play-acting at science.”
Can it get worse? Answer: sure can! • Tacts – comments about the world • Can make observations about the world that refer to the past or future, or to potential events • Example: “There was an elephant at the zoo” • Skinner – “[this] must be understood as a response to current stimuli, including events within the speaker himself”.
Chomsky – the intuitions underlying the whole enterprise are just wrong • Rats learning to press bars is based on ‘drive reduction’ • Driver reduction just looks irrelevant for learning in higher animals • Apes and monkeys will solve complex problems that are simply placed in their cages, with manipulation and exploration of the puzzle as the only reward
Next Time What Chomsky thinks linguistics is (or should be)