Figure 2.

Additive factors logic as applied to repetition priming in three situations. In each case, Task X and Task Y are encoding tasks that have processes in common with a test task that requires processes A, B, and C. Task X begins with the same stimulus as the test task; Task Y ends with the same response as the test task. These tasks are performed at encoding either individually or in combination for any given item. Quantities a, b, and c represent the facilitation obtained when process A, B, or C, respectively, has been practiced once in the encoding phase. Sum = sum of the facilitation effects obtained for Task X alone and Task Y alone; Identical = facilitation for identical repetition of the test task; Combined = facilitation when both Task X and Task Y are both performed on the same item before the final test task. Expectations of facilitation for these three conditions are given for three situations: (1) Processes of Tasks X and Y do not overlap, but together they involve all processes of the Test Task; (2) Processes of Tasks X and Y do not overlap, and together they do not involve all processes of the Test Task; and (3) Processes of Tasks X and Y overlap and together involve all processes of the Test Task. Adapted from Francis, Corral, Jones, and Sáenz (2008).