The spacing effect: Consolidation or differential encoding?

Theoretical explanations of the spacing effect fall into two classes: those that attribute the advantage of two spaced presentations over two massed presentations to better consolidation of the first presentation, and those that attribute the advantage to better encoding of the second presentation. This paper reports an experimental test of the two classes of theory. Rather than manipulate spacing, the experiment varied the information processing difficulty of the activity interpolated between two presentations of an item. Consolidation-type theories imply decreasing consolidation with increasing difficulty of the interpolated activity. In fact, recall performance following two presentations separated by a difficult task was found to be slightly but consistently better than performance following two presentations separated by an easy task. The outcome thus favors encoding-type theories.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32691/1/0000058.pd