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Interactive and additive effects of word frequency and predictability: A fixation-related fMRI study
Poster C118 in Poster Session C, Wednesday, October 25, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
This poster is part of the Sandbox Series.
Sarah Schuster1, Kim-Lara Weiss2, Stefan Hawelka1, Florian Hutzler1; 1University of Salzburg, Centre for Cognitive Neuroscience, 2Uniklinik Köln
It has been argued that the effects of word frequency and predictability are informative with regard to bottom-up and top-down mechanisms during reading. Word frequency is assumed to index bottom-up, whereas word predictability is assumed to index top-down information. However, findings regarding potential interactive effects are inconclusive. An interactive effect would suggest an early lexical locus of contextual top-down mechanisms where both variables are processed concurrently in early stages of word recognition. This would be in line with contemporary neurocognitive theories suggesting early interactions of higher and lower cortical regions influenced by bottom-up and top-down information. An additive effect, to the contrary, would suggest that the processing of contextual top-down influences only occurs post-lexically. We evaluated potential interactions between word frequency and predictability during silent reading by means of functional magnetic resonance imaging and simultaneous eye-tracking in 24 participants (10 male). As opposed to modeling the haemodynamic response in relation to singly presented words, we utilized participants’ first fixation events whilst they read whole sentences for comprehension (i.e., fixation-related fMRI). The eye movement analysis revealed exclusively additive effects. However, our neuroimaging results indicated both additive, as well as interactive effects. Specifically, we observed additive effects in higher-language regions, i.e., in left inferior frontal regions, whereas interactive effects were situated in cortically lower regions, i.e., the left occipito-temporal cortex. Our findings suggest that word frequency and predictability are processed concurrently during lexical processing. In other words, top-down information influences visual word recognition at the stage of lexical retrieval. Especially, the interaction in the left occipito-temporal cortex goes in line with the notion that reading entails a predictive component serving language comprehension.
Topic Areas: Reading, Meaning: Lexical Semantics