Can High Group Cohesion Be Harmful?

High group cohesion is considered to be beneficial and lead to better performance. This qualitative case study describes a case in which high social cohesion led to a deterioration in a team's performance. The aim of the present study was to investigate the relationships between performance in a team sport and social psychological group phenomena such as cohesion, conformity, groupthink, and group polarization. The participants were members of a junior-league ice-hockey team, consisting of three adult coaches and 22 players aged 15 to 16 years. The data were derived from an interview with the main coach, continuous observation by the principal researcher, and a diary based on observations during one ice-hockey season. The Group Environment Questionnaire was used to assess group cohesion quantitatively. The qualitative data were analyzed by identifying themes that illuminated the research problem. In this study, the team did not perform as expected, and their performance deteriorated during the autumn. Social cohesion was high. In addition, the need to evaluate performance declined because of increased pressure to conform. Pressure to conform, groupthink, and group polarization increased owing to the high level of social cohesion which in turn was associated with the deterioration in the group's performance. Based on the findings it appears that high group cohesion may not always be beneficial to the team and does not necessarily lead to better performance in all situations.