Methods of Evolutionary Sciences

This chapter discusses how and why multimethod/multimeasure evidence for the special design of certain traits or behaviors offers more compelling evidence for their status as adaptations. It also discusses the unique inferential and methodological challenges associated with testing evolutionary theories. The chapter reviews classic concepts and issues surrounding validity. It describes the major types of validity and explains why evidence for each type is required to establish construct validity. The chapter also reviews different types of investigative (research) methods that are organized around an adapted model proposed by Runkel and McGrath. This model highlights the trade-offs entailed by the use of each research method. It explains two programs of evolutionary research that have applied multimethod/multimeasure strategies to document the special design features of certain hypothesized psychological adaptations. The chapter concludes by proposing several ways in which current programs of evolutionary research might be strengthened and improved from a methodological standpoint.