Practice effects during repeated administrations of memory tests with and without alternate forms.

Previous research indicates that practice effects are large with repeated versions of memory tests. In contrast, administrations of the same tests using alternate forms typically yield much smaller practice effects. However, most studies do not compare alternate- and same-form conditions directly, and differ widely in terms of test-retest interval, modality of stimuli (verbal, spatial), format of the memory test, and number of examinations. The present study investigated practice effects during repeated administrations of verbal and nonverbal memory tests which have the same administration format. Two groups of healthy participants, matched for age, education, estimated IQ, and baseline memory test performance, were assigned to either a same- or alternate-forms condition. Participants taking the same form every two weeks improved significantly over four sessions. Participants completing alternate forms of the nonverbal memory test produced a small practice gain, but the verbal memory test was resistant to practice effects when alternate forms were used.