Multi-featured objects: Parallel and serial access to all features
23.305, Saturday, May 11, 8:30 am - 12:30 pm, Royal Ballroom 6-8
Amanda E van Lamsweerde1, Melissa R Beck1; 1Louisiana State University
In this study, we tested the ability to have attentional access to two features of an object in parallel. Participants viewed two study features (20-50ms), simultaneously or sequentially, followed by a single test feature. Equal performance for both presentation types indicates parallel access to both features, while higher accuracy for the sequential presentation indicates serial access (Huang & Pashler, 2007). In our two-dimension condition, participants saw a single colored shape (simultaneous presentation) or a colored square and a black shape sequentially. Performance was better for simultaneous presentation, indicating parallel access to both color and shape. In the simultaneous presentation for the single-dimension conditions, two colors or two shapes were adjoined to resemble a single object or separated to resemble two objects. Regardless of the spatial arrangement, performance was equal in the simultaneous and sequential conditions for two colors, indicating that participants could access two different colors in parallel. However, for two shapes, whether the spatial arrangement was separated or adjoined did influence performance. When the shapes were separated, performance was higher in the sequential condition, indicating serial access to the two shape values. When the shapes were adjoined, performance was equal for simultaneous and sequential presentation, as long as both shapes were presented at test. If a single shape was presented at test, performance was higher for the sequential presentation, suggesting that if adjoined shapes are accessed together during the study presentation, they must also be compared together at test. Our results suggest that features from two dimensions (color and shape) can be accessed in parallel, while two features from the same dimension may need to be accessed sequentially, depending on the feature dimension. Uniting two features that are accessed serially into a unified object may allow the participant to access both features in parallel.