Humans do a rough categorization of objects very quickly. For instance, in just a tenth of a second, we can recognize whether something we see is an animal or not. Our results show that this immediate, rough impression probably depends on recognizing just one or more individual parts of what we see. Fine discriminations - such as recognizing individual faces - take longer to happen, and our study suggests that this delay depends upon emerging signals for combinations of shape fragments. In a sense, the brain has to construct an internal representation of an object from disparate pieces.

Charles E. Connor