Spontaneous categorizers retain more than spontaneous alphabetizers.

Immediate and delayed free recall of unstructured verbal materials were assessed for alphabetizers and categorizers after varying study times. Alphabetizers and categorizers did not differ in immediate recall, but retention following a 6-day interval was consistently higher for categorizers than for alphabetizers. Both immediate and delayed recall increased with study time, which did not interact with learning strategy. In the next experiment alphabetizers and categorizers learned two lists, the second of which was categorically structured or unstructured. No retroactive interference on first-list recall was produced by the learning of the structured list, but the learning of the unstructured list produced retroactive interference for the alphabetizers only. It was suggested that, although both alphabetizers and categorizers probably use their respective strategies for other verbal tasks, the categoric strategy should create less interference because specific 'categories are rarely encountered in successive tasks.