Contents

326 PART IV: Applied ResearchFIGURE 10.3Langer and Rodin (1976) used a nonequivalent control group design to study the effect of twodifferent types of responsibility instructions on the behavior of nursing home residents. Becausea “true experiment” was not conducted, the researchers examined features of the study todetermine if any threats to internal validity were present.pretest and posttest measures showed that the residents in the responsibilityinducedgroup were generally happier, more active, and more alert followingthe treatment than were residents in the comparison group. Behavioral measuressuch as frequency of movie attendance also favored the responsibilityinducedgroup, and, although 10 residents from this group entered the jelly beancontest, only 1 resident from the comparison group participated! The investigatorspoint to possible practical implications of these findings. Specifically, theysuggest that some of the negative consequences of aging can be reduced orreversed by giving the elderly the opportunity to make personal decisions andto feel competent.Before turning to the specific limitations associated with this design, let uscall your attention to another feature of the Langer and Rodin study, one thatcharacterizes many experiments in natural settings. The treatment in the Langerand Rodin study actually had several components. For example, residents in thetreatment group were encouraged by the staff to make decisions about a numberof different things (e.g., movies, rooms, etc.), and they were offered a plantto take care of. The experiment evaluated, however, the treatment “package.”That is, the effectiveness of the overall treatment, not individual components