Interactive instructional methods are characterized by engaging students with the course material and involve delivering feedback for their efforts. Using a mixed 2 x 2 factorial experiment, we compared the effects of multiple choice answer formats (word versus letter) and methods (automated versus manual) on 70 undergraduate students' acquisition of instructional material. Although there was no significant difference in participants' gain scores between automated ("clickers") and manual (holding up response cards) methods, significantly greater learning occurred when participants used the word rather than letter answer format. Despite participants' preference for letter over word format, instructors may still want to require students to write out answers to review questions given the improved performance it yields. (Contains 2 figures.)