Recent empirical results suggest that there is a decrement in dividing attention between two objects in a scene compared with focusing attention on a single object. However, objects can be made of indi- vidual parts. Is there a decrement for dividing attention across different parts of a single object? We ad- dressed this question in two experiments. In Experiment 1, we demonstrated that attention can exhibit part-based selection—that is, the subjects were more accurate in reporting two attributes from the same part of an object than they were in reporting attributes from different parts of an object. In Ex- periment 2, we demonstrated that part-based attentional decrements occurred simultaneously with ob- ject-based attentional decrements. The results from Experiment 2 demonstrated that part-based at- tention is evident at the same time as objects are processed as coherent wholes. Our results imply that there is an attentional mechanism that can select either objects or their parts.
Published in 1999.