Investigating the representational modality of dimensional concepts

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Maleah J. Carter¹ (maleah.carter@nih.gov), Christopher I. Baker¹, J. Brendan Ritchie¹; ¹National Institute of Mental Health

Conceptual representation, or the way in which the brain renders any given idea or object, has implications for nearly all aspects of perception and cognition. As a result, there are many theories about how and where concepts are represented, largely based on the usage of categorically defined stimuli (e.g., A vs. B, cats vs. dogs). Dimensional, continuous concepts, which contain no inherent bounds, are often adapted to fit within categorical paradigms (e.g., a concept such as “weight” may be transformed into “light” vs. “heavy”). However, these substitutions may not capture the scalar, relative properties that the original dimensional concept may have contained. The present study seeks to retain the scalar nature of three different dimensional concepts (aspect ratio, weight, and price) and to compare their neural representations to those expected by prior theories of conceptual representation. Five rectangular objects (a lighter, deodorant stick, battery, wallet, and smart TV remote) were organized on scales of each of the three dimensional concepts, such that the scales did not correlate with one another above a threshold of r > .30. Twenty participants will judge the five object images, and object names, during a 1-back comparison task for each dimensional concept, within a 3x2 block design (Aspect Ratio, Weight, Price; Object Images, Object Names) and while undergoing a simultaneous fMRI-EEG scan. We will use whole-brain searchlight representational similarity analysis (RSA) and EEG RSA methods to determine where and when each concept is represented, relative to what a selection of prior theories would predict.

Topic Area: LONG-TERM MEMORY: Semantic