Evaluating the Older Adult Brain Response to Word Pairs Varied By Concreteness and Relationship Type
Open Access
- Author:
- Stochel, Jacquelyn
- Area of Honors:
- Communication Sciences and Disorders
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Chaleece Sandberg (She/Her), Thesis Supervisor
Carol Anne Miller, Thesis Honors Advisor - Keywords:
- Semantics
Concretness
Semantic Relatedness
fMRI
Aging
Language - Abstract:
- Semantics is the part of language that conveys meaning. One factor that influences semantic processing is the concreteness of concepts (i.e., the degree to which a concept evokes the senses). Another factor is semantic relatedness (i.e., how concepts relate to one another). Both factors can interact in the processing of semantic information. Understanding this multifaceted system is valuable to the field of speech-language pathology, as knowledge of normative semantic processes can be leveraged in the design of therapies. However, many of the studies attempting to explain this complex system fail to recruit older adults, making these studies a poor model of normal processing in the majority of individuals with aphasia. This motivates the current work, which aims to study older adult brain responses to word pair stimuli of varying concreteness and relatedness type. Participants included nine neurologically intact adults over the age of 40. All completed a semantic judgment task while in a functional magnetic resonance imaging (fMRI) scanner, and this required participants to judge if word pairs were related or unrelated. Stimuli were different combinations of concreteness and relatedness, enabling both the analysis of main effects and interactions of these semantic factors. Previously observed behavioral interactions of concreteness and relatedness effects were not replicated in this sample. fMRI results did replicate of the patterns previously noted for concreteness processing, but did not replicate for patterns for relatedness processing. This work does not provide evidence to support the different representational frameworks (DRF) hypothesis— which suggests that there are different preferential organizations for abstract versus concrete words—or the dual hub (DH) theory—which postulates that the anterior temporal lobe is a hub taxonomically-related items and that the temporoparietal junction is a hub for thematically-related items. The choice of task is a possible explanation for the lack of DRF replication, and the sample size or the selection of abstract stimuli are possible explanations for the lack of DH replication.