Applications of the Theory of Natural Selection to the Study of Family Communication Kory Floyd Hugh Downs School of Human Communication Arizona State University Mark T. Haynes Hugh Downs School of Human Communication Arizona State University If one’s goal is to account for patterns of variation in the communicative behaviors of family relationships, then we contend that no single theory explains as many aspects of family interaction, or explains them with as much depth, as does Darwin’s (1859) theory of natural selection. In this article, we delineate the major precepts of the the- ory (and of associated theories that have been derived from it) and apply them to a number of relational phenomena in the marital and parent–child subsystems. We then speculate as to why the theory has not been widely used in family communication re- search, despite the breadth and depth of its explanatory power, and we offer sugges- tions to scholars wishing to incorporate principles of natural selection and evolution- ary psychology into their research on families. The family is an extraordinarily rich context for gathering information on human social behavior. The ability to accumulate, contextualize, understand, and draw ap- propriate inferences from such information relies largely on the availability of the- ories that can not only model or predict such behavior but also explain it. Family communication researchers are fortunate to have a number of theories on which to draw. In this article, we describe how Darwin’s (1859) theory of evolution by means of natural selection (TNS) can be used to explain multiple aspects of rela- THE JOURNAL OF FAMILY COMMUNICATION, 5(2), 79–101 Copyright © 2005, Lawrence Erlbaum Associates, Inc. Correspondence concerning this article should be addressed to Kory Floyd, Hugh Downs School of Human Communication, Arizona State University, PO Box 871205, Tempe, AZ 85287–1205. E-mail: kory.floyd@asu.edu