This paper examines how XP practice meets the motivational needs of software developers. Interactions with peers have been identified by others as one potential area of (de)motivation but little detail is known. The nature of this motivator, as expressed by software developers themselves, was explored through semi-structured interviews with a high maturity high performing team working on safety critical software applications in a traditional environment. From these interviews, we have identified seven themes which are characteristic indicators of peer motivation. We interrogate observational data from five mature XP teams to consider whether and how these characteristic indicators are present in an XP environment. We find that XP teams in our study had processes in place that supported many of the motivational needs voiced by developers coming from a traditional, heavyweight software development environment. However, the XP environment is at odds with other motivational needs.