9/22/10Psyc / Ling / Comm 525 Fall 10 Semantic Priming (Phenomenon & Tool)...armkitchentree Related prime >doctoractor < Unrelated prime nurse floor... In a priming experiment: –Some people see nurse immediately after doctor in a list of words = Related condition –Others see nurse after an unrelated word like actor = Unrelated condition - Notice that target word is identical across conditions, so important word properties like frequency & length are perfectly controlled –People respond faster, on average, in Related condition = Priming (= facilitation)

9/22/10Psyc / Ling / Comm 525 Fall 10 Lexical Ambiguity Resolution Many words have multiple meanings –plant, bank, bug, deck,... Ambiguous words occur far more often than we realize We're so good at figuring out which meaning is intended that we rarely notice any ambiguity –How do we do it? –Do we retrieve multiple meanings as part of recognizing the word, & then pick the right meaning for the context? Multiple Access (= Modular) Or does context act to prevent us from ever even retrieving the irrelevant meaning? Selective Access (= Interactive)

9/22/10Psyc / Ling / Comm 525 Fall 10 Ambiguous prime armarmarm windowwindowwindow bookbookbook bugbugbug spyantsew carcarcar Related Unrelated Targets Target In word lists, both related targets show facilitation –Notice, in this design, it’s the prime that stays constant across conditions & the target that differs Have to work hard to control properties of target that affect RT What happens in sentences where it’s clear which meaning is intended? Semantic Priming with Ambiguous Words

9/22/10Psyc / Ling / Comm 525 Fall 10 Notice there’s a clever trick here –Use a prime that has some kind of uncertainty about it Could be visually degraded Or lexically ambiguous –Use targets related to different possible interpretations of prime If the response to a target is facilitated then the interpretation of the prime related to that target must have been “active” –So, using response to target to figure out how prime processed –Can vary time lag between prime & target to tap into prime processing at different points = Stimulus Onset Asynchrony (SOA)

9/22/10Psyc / Ling / Comm 525 Fall 10 Swinney (1979) Cross-modal priming study Primes = auditory sentence containing critical prime word Task = lexical decision on visual targets 4 kinds of auditory prime sentences: The man was surprised when he found several insects in the corner of the room.... bugsin the corner of the room.... spiders, roaches, and other insectsin the corner of the room.... spiders, roaches, and other bugsin the corner of the room. ^ant (contextually approp) spy (contextually inapprop) sew (unrelated) aln (non-word) ^ant spy sew aln

9/22/10Psyc / Ling / Comm 525 Fall 10 Swinney (1989) Notice, very complex design !!! 2 (Context vs No Context) x 2 (Ambiguous vs Unambiguous Prime) x 2 (Prime-Target SOA) x 4 (Target Word Type) = 32 conditions ! –144 participants !

9/22/10Psyc / Ling / Comm 525 Fall 10 Unambiguous Conditions

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9/22/10Psyc / Ling / Comm 525 Fall 10 Swinney's study is important because: –It shows how fast things change during comprehension –It made sense of conflicting previous results whether you get evidence of interaction depends on when measure –The multiple access results are so counterintuitive! More recent results have modified the conclusion: –IF one meaning of an ambiguous word is much more common Swinney didn’t manipulate this property of ambiguous words –AND context strongly supports the more common meaning –THEN, only the contextually appropriate meaning seems to be activated –So, when meaning frequency and context gang up, can get selective access (Duffy, Morris, & Rayner, 1988) Rather than priming for a related target, they measured reading times on ambiguous words and the words after them with an eyetracker Times were just as fast for ambiguous words as for unambiguous control words if there was plenty of context supporting the more frequent meaning of the ambiguous word

9/22/10Psyc / Ling / Comm 525 Fall 10

9/22/10Psyc / Ling / Comm 525 Fall 10

9/22/10Psyc / Ling / Comm 525 Fall 10

9/22/10Psyc / Ling / Comm 525 Fall 10 Van Petten & Kutas (1987) Context always supported less frequent meaning - So, should get priming for targets related to both meanings

9/22/10Psyc / Ling / Comm 525 Fall 10 Naming Time Results At 200 msec SOA, priming smaller but still reliable for contextually inappropriate target At 700 msec SOA, reliable priming only for the contextually appropriate target Replicates the pattern of results in Swinney’s study (statistically, at least) Consistent with Duffy et al.’s frequency effects

9/22/10Psyc / Ling / Comm 525 Fall 10 ERP Results Classic N400 priming effect For first 500 msec, Inapprop patterns with Unrelated Then, changes to become more like Approp target Only Approp target primed Taken as evidence of “backward priming” - ERPs can show this because continuous measure rather than tapping into just one point in time

9/22/10Psyc / Ling / Comm 525 Fall 10 Backward Priming Apparent multiple access at short SOA is artifactual –A target word related to the contextually inappropriate meaning of an ambiguous prime word that is presented while the prime is still being processed causes retrieval of that inappropriate meaning –Maybe that’s why multiple access only at short SOAs Rather than because context selects appropriate meaning quickly after multiple access

9/22/10Psyc / Ling / Comm 525 Fall 10 Another Possibility In many sentences, other words in context could prime the Appropriate target before the ambiguous prime word has any effect at all - So early part of waveform could be due to priming from other words - Then when the ambiguous word is processed sufficiently, it kicks in & primes both targets