Word semantics 4 DAY 29 – nov 4, 2011

WORD SEMANTICS 4DAY 29 – NOV 4, 2011

Brain & LanguageLING 4110-4890-5110-7960NSCI 4110-4891-6110Harry HowardTulane 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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http://www.tulane.edu/~howard/LING4110/

REVIEWThe quiz was the review.

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Linguistic model, Fig. 2.1 p. 37


Discourse model

SyntaxSentence prosody

MorphologyWord prosody

Segmental phonologyperception

Acoustic phonetics Feature extraction

Segmental phonologyproduction

Articulatory phonetics Speech motor control

INPUT

SEMANTICS

Sentence level

Word level

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THE FUNCTIONAL ORGANIZATION OF THE VENTRAL VISUAL PATHWAY AND ITS RELATIONSHIP TO OBJECT RECOGNITIONGrill-Spector 2004


Brain & Language - Harry Howard - Tulane University 611/04/13

The what / ventral pathway (Palmeri & Gauthier 2004)


Basic-level naming extends more anteriorly than domain-level naming, Brodmann's areas

Basic-level naming activates BA 19, 37, 36, 28 (and presumably 20)

Domain-level naming activates BA 19, 37 (and presumably 20)

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Distinctive properties of animals

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LATERALIZATION OF WORD SEMANTICS



Associations for “pig” in LH/RH terms


Test by word grouping

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Group two of these words together (silently!):


Results


Test by semantic priming

LHD preserves

• Summation priming: • shuttle, ground, space >

launch

RHD preserves

• Direct priming: • cut > scissors

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Other RH deficits• Naming category but not function

• hat > pants (category: clothing)• wool *> suit (function: material)

• Naming pictures of collective nouns• plane, car, truck, train = *

• Naming goal-oriented categories• things you take on a camping trip = few (wrt NBD & LHD)


Time course of retrieval of meaning of ambiguous words• Lexical decision priming experiment:

• Use an ambiguous word as the prime (such as BANK) and display one of its meanings as the probe (MONEY or RIVER) to the right or left visual hemifield:

• With a very short amount of time to process the prime word (35 ms):• LH shows priming for both dominant (MONEY) and subordinate

(RIVER) meanings.• RH takes more time to activate both meanings (by at least

300 ms).• At a longer duration (750 ms):

• LH shows no facilitation for the subordinate meaning. • RH shows sustained facilitation for both meanings.


Conclusion• Burgess and Simpson (1988) hypothesized that this difference between short and long duration of inter-stimulus interval (ISI) may be advantageous for the disambiguation of ambiguous words during normal sentence processing:• In normal circumstances, the LH quickly selects an appropriate

meaning and deactivates all inappropriate meanings of the word. • However, in sentences where the LH makes an error in its

selection, the role of the RH may be to supply the alternative meaning.


Two types of semantic processing

Convergent semantic processing

i. … in linguistic tasks which elicit a limited number of responses.

ii. In such tasks, subjects must suppress alternate meanings or select a single best item from many choices.

iii. For instance, a subject may be presented with a noun such as ‘hammer’ and be asked to supply a verb, giving the response ‘(to) pound’.

Divergent semantic processing

i. … in linguistic tasks which elicit a wide number of responses.

ii. In such tasks, subjects must produce alternate meanings or list as many items as possible.

iii. For instance, the experiment just mentioned can be continued by asking the subject to supply yet another verb, resulting in a response such as ‘(to) throw’.

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Message-level information• Size of priming unit: 6 word sentence > 3 word phrase > 1

word > no prime:• LH priming increases incrementally with the number of words.• RH shows equal priming.

• Priming with scrambled vs. syntactically correct sentences:• LH shows greater priming from structured sentences.• RH shows equal priming.

• Priming with congruous ('The patient swallowed the medicine') vs. incongruous sentences ('The patient parked the medicine'):• LH shows greater priming from the congruent sentence. • RH shows equal priming.


Conclusions for message-level info• LH can take advantage of message-level information in a

sentence:• previous context• structure• congruity

• RH processes only at the level of intralexical associations, independently of message-level information.


Summary of lateralization of word semanticsLH RH

a. Slowly selects multiple meanings (divergent processing) that are weakly associated.

b. Primes words that share few semantic features > loosely associated words.

c. Primes the less frequent meaning of an ambiguous word.

d. Primes category, but not others.e. Priming stays same with more

words.f. Priming is same for unstructured

sentences.g. Priming is same for incongruent

sentences.

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a. Quickly selects most familiar or dominant meaning (convergent processing) while suppressing other less closely related meanings.

b. Primes words that share many semantic features > closely associated words.

c. Primes the most frequent meaning of an ambiguous word.

d. Primes function, collectives, goal-oriented classes.

e. Priming is faster with more words.f. Priming is slower for unstructured

sentences.g. Priming is slower for incongruent

sentences.

NEXT TIMEStart part IV. Sentence comprehension. §12 Sentence comprehension and syntactic parsing

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Word semantics 4 DAY 29 – nov 4, 2011

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