MODULARITYDAY 13 – SEPT 25, 2013

Brain & Language

LING 4110-4890-5110-7960

NSCI 4110-4891-6110

Harry Howard

Tulane University

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Course organization• The syllabus, these slides and my recordings are

available at http://www.tulane.edu/~howard/LING4110/.• If you want to learn more about EEG and neurolinguistics,

you are welcome to participate in my lab. This is also a good way to get started on an honor's thesis.

• The grades are posted to Blackboard.

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REVIEWEEG, ERP & MEG

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The basic fact about dipoles

A dipole has a direction … … which in cortex is perpendicular to its surface

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Language areas of the brain

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The Broca-Wernicke-Lichtheim model (of the LH)

MODULARITYIngram §4

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But first …

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Fodor’s criteria for modularityProperty Vision Language

Specific to a domain color & edge detectors phonetic feature detectors

Operates mandatorily you can’t stop seeing (with your eyes open)

you can’t stop hearing English as English

Limits central access how do you see? how do you hear English as English?

Acts quickly image recognition < 200ms? word recognition < 200 ms?

Information is encapsulated

other senses don’t affect vision (but synesthesia)

other senses don’t affect speech recognition

Analyzes ‘shallowly’ early vision extracts edges early language only assigns superficial structure

Fixed neural structure eg V1 perisylvian region

Fails in a specific way visual agnosia BWL model

Matures in a specific way (?) stages in child acquisition

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The problem• Fodor’s nine properties of modularity are organized

haphazardly.• They should be grouped into those that are necessary to any sort

of modular process, and those that are just by-products of modularity, perhaps in a specific process.

• We do this in the next slide.

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Coltheart’s grouping & my explanation

1. Specific to a domain

2. Information is encapsulated

3. Fixed neural structure

4. Matures in a specific way

5. Fails in a specific way

6. Limits central access

7. Operates mandatorily

8. Acts quickly

9. Analyzes ‘shallowly’

1. by definition.

2. by definition.

3. in order to keep out all the other stuff.

4. in order to build the fixed structure.

5. because it was built in a specific way.

6. in order to keep out other stuff.

7. since there is no external access, it can’t be turned on or off.

8. because there is no other stuff to get in the way of optimizing speed.

9. because other stuff is necessary to analyze deeply.

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A new problem: What is meant by ‘built’?

• If it means, ‘constructed by neurogenesis in the developing brain’ …• … then the only modular abilities are sensory and motor, plus

language.• [NOTE: sensory and motor pathways are peripheral in the nervous

system.]• This is what Fodor means, and what Chomsky means, too.• Language has to be a mutation, added to the others.

• However, if it means ‘learned’ …• … then we may have dozens of modular abilities.• This is what Coltheart means.• Coltheart was inspired by connectionism, a mathematical technique for

teaching computers how to learn, which gained popularity in the mid-80s, before Fodor’s work.

• Language could be entirely learned.

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So how can Coltheart know?

dementia aphasia

cognition ✖ ✔

language ✔ ✖

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By a double disassociation.My example:

If you don’t understand this, read about Coltheart’s example of the chocolate factory.

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Summary• Fodor asks, given some notion of modularity, is there any

cognitive ability that satisfies it?• Yes, following the nine criteria, just peripheral sensory and motor

processing, plus language.

• Coltheart asks, given some cognitive ability, is it modular?• Yes, following just the top two criteria, just about any cognitive

ability could be modular.• Connectionism supplies a theory of learning that shows how this

could happen.

• The truth is somewhere between the two.• Language is learned, but humans have a genetic predisposition

(given by specific neural pathways) to learn it quickly and accurately.

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NEXT TIMEIngram §5.

☞ Go over questions at end of chapter.

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