LEXICAL INTERFACE 5 NOV 2, 2015 – DAY 28 Brain & Language LING NSCI Fall 2015

Course organization Schedule: topics topics Today's chapter: Fun with Quiz before Thanksgiving will be in class & on Blackboard. 11/02/15Brain & Language - Harry Howard - Tulane University 2

Grades Q1Q2Q3Q4Q5Q6 MIN AVG MAX 10 11/02/15Brain & Language - Harry Howard - Tulane University 3

THE LEXICAL INTERFACE 4 The quiz was the review 11/02/15Brain & Language - Harry Howard - Tulane University 4

LEXICAL SEMANTICS 5 11/02/15Brain & Language - Harry Howard - Tulane University 5

Test by word grouping 11/02/15Brain & Language - Harry Howard - Tulane University 6 Group two of these words together (silently!):

11/02/15Brain & Language - Harry Howard - Tulane University 7 Results

Test by semantic priming LHD preserves Summation priming: shuttle, ground, space > launch RHD preserves Direct priming: cut > scissors 11/02/15Brain & Language - Harry Howard - Tulane University 8

11/02/15Brain & Language - Harry Howard - Tulane University 9 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)

11/02/15Brain & Language - Harry Howard - Tulane University 10 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.

11/02/15Brain & Language - Harry Howard - Tulane University 11 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’. 11/02/15Brain & Language - Harry Howard - Tulane University 12

11/02/15Brain & Language - Harry Howard - Tulane University 13 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.

11/02/15Brain & Language - Harry Howard - Tulane University 14 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 semantics LHRH 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. 11/02/15Brain & Language - Harry Howard - Tulane University 15 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.

11/02/15Brain & Language - Harry Howard - Tulane University 16 Associations for “pig” in LH/RH terms

Final project Improve a Wikipedia article about any of the topics mentioned in class or any other topic broadly related to neurolinguistics. Write a short essay explaining what you did and why you did it. Print the article before you improve it, highlighting any subtractions. Print the article after you improve it, highlighting your additions. 11/02/15Brain & Language - Harry Howard - Tulane University 17

NEXT TIME Move to morphology/syntax 11/02/15Brain & Language - Harry Howard - Tulane University 18