Incidental memory of differently processed odors

10 odors were presented to three different groups of 20 subjects each (10 men and 10 women) to investigate the relationships among encoding conditions and both immediate and delayed incidental recognition of odors. Subjects who were not told to memorize the material and not informed of the final recognition test had to evaluate the intensity of each odor (Task 1), to judge the similarity of each odor to mint (Task 2), or to score each odor for pleasantness and sourness (Task 3). The subjects had to recognize test odors, represented one at a time, together with some distractors, immediately thereafter (Immediate Test) and one week later (Delayed Test). Task 1 and Task 2 produced better performances (77% and 75% of items recognized immediately; 66% and 69% recognized after a week) than Task 1. The performance on Task 3, more conceptually driven, was the worst, both immediately (67%) and a week later (52%). Sex and task reliably interacted: women performed better than men on Tasks 1 and 3, men on Task 2. Accuracy did not vary by task but by test time (immediate or delayed). Better performance on Tasks 1 and 2 may depend not only on more effective storage but also on the better fit between the task and the test.