Interactivity in lexical access The modularity debate

Outline Modularity: who cares anyway? Discreteness in production –‘maximalism’ and ‘minimalism’ –Discreteness in the Levelt et al. theory Arguments for discrete stages in lexical access Arguments against it.

Modularity Fodor (1983): –Central systems and Input systems (modules) –Modules: Domain specific (color perception, parsing) Mandatory (You’re mad if you read this!) Limited central access (tree structure rapidly gone) Fast (reflex-like) Informationally encapsulated (no feedback) Shallow outputs (only necessary information)

Does production consist of modules? Fodor: ‘language’ is a module Hidden assumption in many current theories: –Language production consists of a series of stages / levels, each of which is a module –Stages discovered using the Donders / Sternberg additive factors logic

Additive factors logic Suppose you manipulate variable X (e.g., animacy) and variable Y (e.g., frequency) let’s say in picture naming. If there are main effects of X and Y, but there is no interaction -> they affect separate stages. If X and Y show main effects and interact, - > they affect the same stage.

Minimalism Minimal input: a process occurring at stage n, will pass to stage n+1 only the minimal, necessary information (cf. Fodor, ‘shallow output’). Unidirectional information flow: level n will pass information to level n+1, but level n+1 does not send information back to n.

Levelt et al.’s maximalism 1. Lemma retrieval is NOT minimal: –Maximal input: lemmas get activation from all activated lexical concepts. –Bidirectionality: lemmas activate lexical concepts.

Levelt et al.’s minimalism 2. Word-form retrieval IS minimal: –Minimal input: The selected lemma and only the selected lemma, will send activation to the word forms (the assumption of non-cascading). –Unidirectional flow: the word form does not send activation back to the lemma.

Why is word-form retrieval minimal (1)? Parsimony (‘Occam’s razor): a theory should minimize its assumptions (theoretical constructs, ad-hoc mechanisms). Thus, it is better to have a theory without cascading and without feedback, if the data don’t force us to.

Why is word-form retrieval minimal (2)? The alternative is not logical. If the lemmas which are active but which are not selected activate their word forms, this will hinder the encoding of the target. Thus, to preserve accuracy, special mechanisms would be needed to prevent this hindrance. A ‘baroque’ theory.

Why is word-form retrieval minimal (3)? Levelt et al. (1991). Picture naming + auditory probe (SOA = 73 ms) Lexical decision on the probe. Is it word or a nonword? Latencies corrected with condition without picture.

Why is word-form retrieval minimal (3-ii)? One experiment: Target Sheep, probes Sheet and Pen. Faster lexical decision for Sheet. Crucial experiment: Semantic, Identical, Phonologically related to semantic, unrelated: Sheep, goat, goal, pen. Sem = Id >> PhtoS = Unr

Why is word-form encoding minimal? (4) There is no reaction time evidence for this (i.e., from word form to lemma selection) proposed feedback mechanism (Levelt et al., 1999, p. 17) To anticipate: that claim is controversial. Levelt et al. have a different explanation.

Why is word-form encoding maximal? (max input 1) Peterson & Savoy (1998): similar paradigm as Levelt et al. (1991), naming iso LD Near Synonyms: couch and sofa After naming a picture as a COUCH, there was priming for the naming of the word SODA. Only for near-synonyms.

Why is word-form encoding maximal? (max input 2) Cutting and Ferreira (1998): Picture/word interference. Target Picture: Ball (like in football). Distractor: Dance (sem. related to homophone): Facilitation (Dance activates lemma Ball, and both Ball- lemmas activate the word form)

Why is word form retrieval maximal? (max input 3) Blends: it didn’t bother me in the sleast … slightest [presumably: least and slightest; Boomer & Laver, 1968]. Often near-synonyms, partially encoded in one utterance. Both lemmas spread activation to the form level.

Why is word form retrieval maximal? (max input 4) Mixed erors occur more often than chance would predict (Dell & Reich, 1981) –Rat -> Cat; Oyster -> Lobster Why? –Form-to-lemma feedback yields semantic error (traditional account) –Cascading yields phonological error (V & H)

Why is word form retrieval maximal? (bidirectionality 1) Starreveld & LaHeij (1995) -- Picture/word interference Distractors: semantic, phonological, semantic AND phonological, unrelated. Target: CAT, Distractors: Sheep, Car, Calf, Pen. Sem interference and Phonological facilitation; PLUS AN INTERACTION.

Why is word form retrieval maximal? (bidirectionality 1-i) Thus, the semantic interference effect for the mixed case (CALF) was smaller than what you’d get if you add up the semantic and phonological effects. Note: their interpretation: the lemma does not exist (cf. Caramazza & Miozzo, 1997).

Why is word form retrieval maximal? (bidirectionality 2) Damian & Martin (1999, Expt 3). Similar to Starreveld & LaHeij, but with auditory distractors. Again, a clear interaction between form and meaning. Their interpretation: feedback

Why is word form retrieval maximal? (bidirectionality 3) Harley & Brown (1998) TOT states: more likely for words in a low density neighbourhood. Recall, that often some phonological info available. The more word forms compatible with it, the more feedback they can send to the lemma.

The Levelt et al. reply Blends, near-synonym effects: special mechanism: selection of 2 lemmas. Extension of this mechanism to other cases Self-monitoring mechanisms (mixed errors more difficult to edit out) Input account.

Back to Fodor... “The claim that input systems are informationally capsulated must be very carefully distinguished from the claim that there is top-down information flow within these systems” (p. 76).