Recent empirical results suggest that there is a decrement in dividing attention between two objects in a scene compared to focusing attention on a single object. However, objects may be made of individual parts. Is there a decrement for dividing attention across different parts of a single object?

We are addressing this question in a series of studies. Using multi-part objects, we have shown that attention can exhibit part-based selection: Subjects are more accurate in reporting two features from the same part of an object than from different parts of an object. This part-based attentional decrements occurs simultaneously with object-based attention. Additional studies suggest that part-based attentional selection is not due to spatial selection. Parts, not the locations of parts, can be selectively attended.

Experiments we have in progress explore part-based attention in faces. The theoretical question of interest is whether part-based attention and object representation are part of a single system or are separate processes.

Using face stimuli such as those shown below, viewers report features of the eyes (eye shape, eye separation) and the nose (nose shape, nose width). Faces show a part-based attention effect: Viewers are more accurate in reporting features from the same part than from different parts, suggesting that part-based attention can decompose configural face representations. Preliminary results from the face part-based attention task were presented at Psychonomics in 2002, and the slides from this talk are available here.