It seems counter-intuitive and yet it is true:
When team members work hard and learn new things, it can hinder team performance instead of boosting it.
One mundane reason is that sometimes learning isn’t necessary at all, because simply working a little harder will do. MIT researchers Nelson Repenning and John Sterman have called this “working harder versus working smarter.” Another MIT researcher, Elaine Lizeo, went even further: she found that individual team members learning alone increased productivity, but not team performance. It is only when the team agrees that performance needs to improve and what steps need to be taken to achieve this that the performance of the whole team, and not just the individual members, develops. Even the best conditions only lead to better performance if there is trust and the will to perform within the team. Lizeo regards the common performance ambition and the psychological safety that form the basis for team learning as “team capacity”. A comparison of the effectiveness of “learning” and “team capacity” shows that it is not the learning of the team members that improves team performance, but only the sustained increase in team capacity.
Prof. Dr. Joachim Hasebrook and Dr. Sibyll Rodde explain the details in their book “Team-Mind und Teamleistung” (Team Mind and Team Performance) in the chapter “Viele Hände schaffen am falschen Ende: Wie Teamleistung entsteht” (Many hands working at the wrong end: How team performance is generated”. The chapter contains an interview with the chairman of the German Handball Federation, Wolfgang Sommerfeld, on the subject of team performance. The book is only available in German.