OBJECT ORIENTATION INFORMATION IN SEMANTIC AND EPISODIC MEMORY

The time required to identify a common object depends on several facto rs, especially pre-existing knowledge in semantic memory, and episodic representations newly established as a result of a prior,study. We re port three experiments that investigated the relative contribution of these factors to implicit and explicit memory test performance. In eac h experiment, subjects were shown color photos of objects and memory w as assessed either with an old/new recognition test or with a test tha t required them to identify objects that were slowly faded in on a com puter monitor. The critical variables were the type of photo - each sh owing either an object with a predominant or cardinal orientation (e.g ., helicopter) or a non-cardinal object (e.g., pencil), and the orient ation at which the photos-were displayed at study and at test (e.g., o n the plane of the page at 0 degrees, 120 degrees, 180 degrees, 240 de grees). For each subject, half of the targets were shown at study and all appeared on the test, with targets displayed either in the same or ientation as at study or in a different orientation. For non-studied t argets (i.e., in the baseline condition), identification test performa nce showed a huge effect due to display orientation, but only for card inal objects. For studied targets, identification test performance sho wed substantial priming in all conditions, with more priming on cardin al than non-cardinal targets, especially when their display orientatio n at test was unusual (i.e., 120 degrees, 240 degrees) and the same as at study. We use these findings to discuss the extent to which orient ation information is coded in the semantic and episodic memory represe ntations of different kinds of objects.