Abstract
As we look around the world, we identify items along many dimensions, such as color (looking for red as you search for an apple) and shape (looking for skinny rods as you search for a writing implement). Which dimension we prioritize may change, depending on our current goals. Using a task-switching paradigm, we examined whether certain feature dimensions are prioritized over others in visual processing of objects, ensembles, and social stimuli (e.g., animate creatures). On each trial, participants matched a target stimulus to one of two probe stimuli according to a particular dimension, such as color. After a few trials, the relevant dimension switched, forcing participants to focus on a previously ignored dimension (shape, in this case). We also investigated whether there was an asymmetry in switch costs; that is, whether it is easier to switch from one dimension to another (e.g., color to shape) than vice versa (e.g., shape to color). In Experiments 1a and 1b, participants sorted individual objects and homogeneous ensembles. As expected, switches in the sorting dimension led to increased reaction times. Furthermore, participants incurred a larger cost when switching from color to shape than vice versa, suggesting that color may be prioritized over shape for both individual objects and for homogeneous ensembles. In Experiment 2, participants sorted individual objects and heterogeneous ensembles. Switch costs were again observed; however, participants did not exhibit asymmetric switch costs for color or shape. In Experiment 3, participants sorted social stimuli. Switch costs were observed, and once again, participants exhibited a greater switch cost for switching from color to shape than vice versa. Together, these results suggest that while color is prioritized over shape in perception of objects and social stimuli, this may not be the case for heterogeneous ensembles. This underscores the importance of context in featural processing.
Meeting abstract presented at VSS 2017