The types of roles played by members of small groups have been describ
ed from a number of different perspectives. Most of the research has b
een based on laboratory or therapy-like groups in their ''task-oriente
d'' phase, after the overall purpose of the group has been given, reso
urces supplied, and basic formal roles indicated. Informal roles tend
to develop as a response to the set of formal roles. They may provide
additional activities necessary for effective group functioning or the
y may be in opposition to the formal roles. Little attention has been
paid to groups beginning de novo. However roles are described, they mu
st be placed, eventually, along with other concepts in a comprehensive
social-psychological theory. As an illustration, several category sys
tems, derived from different social-psychological perspectives, can be
used to describe the form and content of formal, informal, and dramat
urgical roles in small groups.