The document discusses two models of group development: the five-stage model and the punctuated-equilibrium model. It notes that both models should be considered when understanding how groups develop and function. Key stages in the five-stage model include forming, storming, norming, performing, and adjourning. The punctuated-equilibrium model emphasizes time as a factor and notes a midpoint of change. The document also discusses factors that influence group behavior, types of groups, and considerations for building high-performance teams.