Babel's Dawn

Broaca's Area Grew

I’m away this weekend celebrating the marriage of a friend of more than 30 years. However, I can at least mention that a team at George Washington University has published a study of the “Broca’s Area Homologue in Chimpanzees” in the Cerebral Cortex journal. It agrees with previous reports that areas 44 and 45 in the chimpanzee brain are homologous to Broca’s area in humans, but reports that Broca’s area in humans is significantly larger “possibly as an adaptation for our species’ language abilities.” (Abstract here)

Poverty of the Stimulus: Part 4, Guest Defends Skinner

B.F. Skinner has taken the occasional hit on this blog, but at last somebody speaks up for him.

Note: This week's series of posts came in response to a bibliography posted by commenter, Ray Weitzman, a retired professor of linguistics who taught for 34 years at California State University, Fresno. He was trained in Chomskyan linguistics and specialized in phonetics and phonology. He also taught Japanese. I contacted him before the series began to appear and he kindly agreed to provide the following response.

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The blogger’s  introductory post perpetuates a number of myths, mischaracterizations, inexact comparisons, and false analogies regarding Skinner’s approach to understanding behavior, particularly language behavior.  I don’t blame the blogger for this; he is just the vehicle for perpetuating these urban legends.  I blame the current Zeitgeist.

Poverty of the Stimulus: Part 3 Non-Nativists

"Angelina Jolie" has at least three meanings: (1) the name of an actress; (2) any beautiful woman; or (3) any unattractive woman.

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The past two posts have looked at the poverty of stimulus argument. Post 1 (here) showed how Chomsky used it to overthrow Skinner’s operant-conditioning based theory of language learning. Post 2 (here) explained why I argue on this blog that while the poverty of the stimulus argument destroys Skinner, it does not mean that Chomsky’s defense of an innate, universal grammar (UG) is required.

In this post I want to look at an alternate empiricist response to Chomsky. In an earlier post I wrote about the spontaneous creation of tools by a form of crow, and what this might imply about speech and motivation. (See: Motivation and Speech)

The post inspired a lively exchange. Commenter Raymondw said in part:

What Bird and Emery have demonstrated, as has been demonstrated thousands and thousands of times, is the power of operant conditioning as a learning tool in most species of life.

And I replied:

I'm not sure what in the abstract leads to the suspicion that operant conditioning was used, unless one argues that everything done by anyone at any time is the result of operant conditioning. That was the doctrine Chomsky exploded 50+ years ago.

And Raymondw responded (in part):

it is highly arguable that Chomsky exploded anything. It has never been experimentally demonstrated that operant conditioning is not the basis for language learning. All Chomsky did is argue verbally in a way that convinced many people that operant conditioning couldn't be the basis for language learning. Let's clear about this. This isn't an issue of competing ideologies but of empirical fact.

Well, that woke me up.

Poverty of the Stimulus: Part 2 Solutions

Which will it be? He hit the ball she threw, or The ball hit him she threw.

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Yesterday’s post (here) summarized Noam Chomsky’s victory over behaviorism with his “poverty of the stimulus” paradox, holding that you cannot determine the rules for organizing sentences simply by studying the physical organization of sentences. Today I want to look at possible solutions to the paradox.

Chomsky himself had a solution: between the input and the output lies computation, and the computational system has been preprogrammed to accept certain structures and reject others. This “universal grammar” (often called UG) is inherent in all natural languages. Although there are many conceivable objections to this proposed solution, Chomsky won himself pride of place in the struggle by having overcome the old champion, B.F. Skinner and for many years the dispute was framed between Skinner’s learning theory and Chomsky’s notion of an innate universal grammar.

Poverty of the Stimulus: Part 1 Chomsky 1959

Noam Chomsky long ago. The pen and notebook in the pocket marks the pre-PDA intellectual. (For larger photo see source.)

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Commenter Raymondw provided a reading list for behaviorist rebuttals to Noam Chomsky’s poverty of the stimulus argument. (They are here) It is a valuable list and I hope blog visitors will check it out. This week I’m going to make several posts surveying the “poverty of the stimulus” question and at the end the commenter will provide his reaction to my pontificating.

The Chomskyan revolution is commonly dated to publication of his Syntactic Structures (1957) but I date it a little later, to the 1959 publication of his review of B.F. Skinner’s book Verbal Behavior. (review here) In the 1950s Skinner was considered America’s most important psychologist. He did extensive experimental work with pigeons, training them to do many things using a method called operant conditioning, and he showed beyond the shadow of a doubt that animals could be trained to behave in many surprising ways if the behavior was rewarded. (Punishment worked less well than rewards.) What made Skinner controversial was his insistence that all learning could be explained in terms of a stimulus (feature of the environment) and response (behavior). In today’s computer world we would say input and output, but Skinner didn’t care about internal computations any more than he cared about personal thoughts. Behavior was to be explained under the Newtonian concept of cause and effect, just as the behavior of a billiard ball can be completely explained in terms of the forces striking the ball and setting it in motion.

Shboy! Shboy!

Wouldn't you be surprised if this fellow (a cotton-top tamarin) started correcting your grammar?

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Wow! Sometimes interesting work gets buried in hype, turning something worth noticing into something that needs to be debunked. In this case a group of psychologists led by Ansgar Endress reported in Biology Letters about finding “Evidence of an evolutionary precursor to human language affixation in a non-human primate” (abstract here; prepub draft here). The mild conclusion is:

some of the computational mechanisms subserving [the tested linguistic task] in a diversity of languages are shared with other animals, relying on basic perceptual or memory primitives that evolved for non-linguistic functions.

In other words, language, including syntax, builds—at least in part—on pre-existing abilities that are older than humans. The point has long been insisted a priori. Now we are starting to get experimental evidence. When I first read the work, I thought I would report on it as providing further support for this blog’s position that speech builds on perceptual abilities. Then I began reading how the story was being covered:

• New Scientist (lede): “Primates can intuitively recognize some rules of grammar.” (here)
• National Geographic News (headline): “Monkeys Recognize Poor Grammar” (here)
• BBC News (headline): “Monkeys recognize ‘bad grammar’” (here)
• RedOrbit (headline): “Monkeys Understand Unspoken Complexities of Language” (here)

Speech Circuitry

Sketch of proposed circuitry supporting phonological loop. The auditory region of the brain associated with speech (Broca's area and adjacent regions) shown under red shading is connected to the motor area controlling vocalization (Wernicke's area and neighboring regions). The connection is sketched under black shading. The numbers shown roughly identify the Broadmann regions.

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One of the mysteries of language is the way, when it is viewed whole, there is nothing else like it in the biological world, but if the view focuses on a part—recognizing voices, making sounds, voluntary actions, voluntary attention, etc.—it seems quite like other phenomena in the animal world. The reaction of analytical thinkers to this mystery is to look about for the part that is not duplicated elsewhere in the animal kingdom—symbols, recursive syntax, displaced reference, etc. Each of these traits fails when put to a simple test: provide a sample of language that lacks the trait, and you still get something unknown to the rest of biology.

Linguistic richness has to be explained, both psychologically and physically. During the past week I read a paper suggesting the clarity can come by focusing on physical explanations.