A comparison of item and source forgetting.

The purpose of the present research was to compare memory for an item with memory for the item's source. Experiment 1 investigated discrimination between two external sources: each item in a list of words was spoken in either a male or a female voice. Subjects received a test of item recognition and a test of source monitoring at each of four delay intervals (immediate, 30 min, 48 h, 1 week). In contrast with previous research, no evidence of differential forgetting rates for item and source information was found. With delay intervals of 0 and 48 h, Experiment 2 replicated Experiment 1 while adding a reality monitoring condition that required discrimination between an internal (i.e., self-generated) and an external source. Subjects were better at making internal-external discriminations than at making external-external discriminations, but both types of source monitoring declined at the same rate as memory for the items themselves.