  Context: Prior research has established that a few individuals generally
dominate project communication and source code changes during software
development, regardless of task assignments at project initiation. Objective:
While this phenomenon has been noted, prior research has not sought to
understand these dominant individuals. Previous work has found that core
communicators are the gatekeepers of their teams' knowledge, and the
performance of these members was correlated with their teams' success. Building
on this work, we have employed a longitudinal approach to study the way core
developers' attitudes, knowledge sharing behaviors and task performance change
over the course of their project. Method: We first used Social Network Analysis
(SNA) and standard statistical analysis techniques to identify and select
artifacts and central practitioners from ten different software development
teams. We then applied psycholinguistic analysis and directed content analysis
(CA) techniques to interpret the content of these practitioners' messages.
Finally, we inspected core developers' activities at various points in time
during systems' development. Results: Among our findings, we observe that core
developers' attitudes and knowledge sharing behaviors were linked to their
involvement in actual software development and the demands of their wider
project teams. However, core developers appeared to naturally possess high
levels of insightful characteristics. Conclusion: Project performance would
likely benefit from strategies aimed at surrounding core developers with other
competent communicators. Core developers should also be supported by a wider
team who are willing to ask questions and challenge their ideas. Finally, the
availability of adequate communication channels would help with maintaining
positive team climate especially in distributed developments.(Abridged)
