This chapter examines how music fits into the evolution of human cognitive capabilities and how the auditory system, larynx, motor systems, and cephalic expansion underlie musical expression as well as the evolution of social contact. The specific adaptation for decoding facial responses, and the more general aptitudes such as applying numerical capabilities to diverse problems, pervade a biological understanding of cognitive adaptation. Cognitive systems are distributed across neural systems that traverse the brain stem to the forebrain. The chapter first provides an overview of some of the core features of problem solving and human expression before discussing the concepts of time and calculations that are embedded in our cognitive capabilities. It also explores the importance of hearing and vocal expression for music and concludes by suggesting that the roots of music may be in the inherent shared features of our social brain.