Role of Features and Categories in Representing Object Knowledge

Abstract

Understanding how our knowledge about the world is organized can help us understand how we are able to access that knowledge to easily identify objects and communicate with others. One general view of object knowledge organization assumes that object knowledge is represented by how we perceive and interact with objects (for example features like the color or shape we see and touch) (i.e., feature view; e.g., Allport, 1985; Barsalou, 1999, 2008; Gallese & Lakoff, 2005; Tyler & Moss, 2001). In contrast, an alternative view hypothesizes that in addition to features from different modalities (e.g., visual, motor, and tactile), taxonomic (e.g., dog and rabbit are animal) and thematic category information (e.g., eating theme: a dog is chewing a bone) is also critical for representing object knowledge (i.e., feature-plus-category view; e.g., Crutch & Warrington, 2005, 2010; Patterson et al., 2007; Schwartz et al., 2011; Mirman & Graziano, 2012). In order to examine these two general views of object knowledge organization, I investigated whether feature and category information is activated when people access the meaning of words using both behavioral (i.e., response times and errors; Experiments 1 and 2) and functional magnetic resonance neuroimaging measures (Experiment 3). Consistent with the feature-plus-category view, Experiments 1 and 2 showed that when people access the meaning of words, this access was affected (slower/faster) by manipulating visual features (e.g., shape), taxonomic and thematic category information associated with objects. In support of the feature-plus-category view, Experiment 3 revealed that action features (e.g., cutting) associated with objects (e.g., saw) activated the motor brain region (i.e., primary motor cortex) and the taxonomic and thematic categories recruited the bilateral anterior temporal lobes and left temporo-parietal junction respectively. Taken together, my dissertation provides converging evidence from both behavioral and neuroimaging perspectives showing that both feature and category information play a key role in representing object concepts.