Abstract
Using inexpensive equipment and a limited number of subjects, this exercise demonstrates, through a factorial design, an interaction between genetics and environment. It also provides experience in direct observation of behavior. Inbred albino and pigmented mice are individually observed in a bright or dim open field; students record activity and defecation. Under dim light, albino and pigmented mice both show high levels of activity; under bright light, the activity of albino mice is suppressed but that of pigmented mice is little affected. Albinoss defecate more than pigmented under both lighting conditions. Significant results are usually obtained with as few as four mice in each of the four groups.