Recognition without picture identification: geons as components of the pictorial memory trace.

Participants viewed a list of black-and-white line drawings and were then presented with a picture fragment identification task in which half of the fragments corresponded to studied pictures and half corresponded to unstudied pictures. In addition to trying to identify each picture fragment, participants gave a rating to indicate the likelihood that the fragment came from a studied picture. When participants could not identify the picture fragments, they were still able to discriminate between fragments that came from studied pictures and fragments that came from unstudied pictures (as shown by their recognition ratings), but only when the fragments contained information about the geometric components (geons) that underlay the original pictures. No recognition without identification was found when the fragments contained only line segment information.