Constructing meaning: Task demands and the time course of lexical and semantic processing in visual word recognition

atmire.migration.oldid1769
dc.contributor.advisorPexman, Penny
dc.contributor.authorHargreaves, Ian
dc.date.accessioned2014-01-14T18:44:51Z
dc.date.available2014-03-15T07:00:17Z
dc.date.issued2014-01-14
dc.date.submitted2014en
dc.description.abstractThe ultimate goal of word recognition is accessing meaning, indeed, the desire to characterize how and when words contact meaning has driven the development of numerous computational models (e.g., Coltheart et al., 2001; McRae, de Sa & Seidenberg, 1997; Morton, 1969). While progress has been made, there is still little agreement between models when it comes to semantic representation. Many studies suggest that semantic access is not a unitary phenomenon, but is better characterized as a diverse set of processes that construct meaning in order to suit the current context (Yap et al., 2012). Across two studies we investigated the dynamic nature of semantic processing. First, we investigated the relative availability of language- and object-based semantic information by tracking the time course of semantic richness effects in word recognition using a signal-to-respond (STR) paradigm fitted to a lexical decision (LDT) and a semantic categorization (SCT) task. We used linear mixed effects to examine the relative contributions of language-based (number of senses, ARC) and object-based (imageability, number of features, body-object interaction ratings) descriptions of semantic richness at four STR durations (75, 100, 200, and 400 milliseconds). Results showed an early influence of number of senses and ARC in the SCT. In both LDT and SCT, object-based effects were the last to influence participants’ decision latencies. Second, we expanded upon our investigation of task-effects on semantic activation by contrasting the event-related potentials associated with two semantic categorization tasks (SCT) using electroencephalography. The two SCTs involved different decision categories: is it an animal? vs. is it a concrete thing? Participants completed both tasks and, across participants, the same core set of items was presented. Despite null differences in reaction time, under the concreteness decision we observed greater negativities in an N400 window (300-500) than when the same items were presented under the animal decision. This task-driven N400 concreteness effect suggests that top down modulation of semantic processing can be elicited by minor shifts in decision criteria. We interpret our results within a framework in which conceptual representations are not simply accessed from memory, but are dynamically constructed (Kiefer, 2012; Kutas & Federmeier, 2011).en_US
dc.identifier.citationHargreaves, I. (2014). Constructing meaning: Task demands and the time course of lexical and semantic processing in visual word recognition (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25428en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/25428
dc.identifier.urihttp://hdl.handle.net/11023/1252
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectPsychology
dc.subjectPsychology--Cognitive
dc.subjectPsychology--Experimental
dc.subject.classificationlexical semanticsen_US
dc.subject.classificationsemantic richnessen_US
dc.subject.classificationvisual word recognitionen_US
dc.subject.classificationsignal to respond procedureen_US
dc.subject.classificationtime courseen_US
dc.titleConstructing meaning: Task demands and the time course of lexical and semantic processing in visual word recognition
dc.typedoctoral thesis
thesis.degree.disciplinePsychology
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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