Behavior analysis is a descriptive science popularized by B. F. Skinner, his students and followers. The aim of this natural science has been the quest for lawful individual behavioral processes studied extensively with within-subject experimental designs. Behavior analysis is particularly concerned with the interplay between behavior and environmental variables. The field is built on extensive experiments with the aim of discovering lawful behavioral processes relevant for consumer research as consumers learn to adapt to their economic environment. In-store consumer behavior, the topic of this chapter, was until rather recently an unexplored territory for behavior analysis. We will here introduce the quest for behavior analysis of instore consumer behavior, how it deviates from traditional marketing, what has been gained, and problems and possibilities for more refined experimental control over this important economic environmental-behavior relationship for the future of retailing.