A leader's mood transfers to the group, with mixed effects

Leaders' moods were experimentally manipulated. When leaders were in a positive rather than negative mood, individual group members experienced more positive and less negative mood, and groups had a more positive affective tone. Groups with positive-mood leaders showed more coordination and expended less effort than groups with negative-mood leaders.

It is the empirical version of something every experienced leader already suspects: the room takes its temperature from the front. That transfer is what makes Attitude a leadership trait rather than a private matter, and it is the honest justification for treating it as one of the twelve.

The complication is what makes it worth teaching. Positive mood did not simply produce more of everything - it produced better coordination and less effort. A leader's cheerfulness can lower the sense of urgency in the room. That is a more useful thing to teach a shift supervisor than "stay positive", and it protects the module from becoming a lecture about smiling.

Note also the direction of responsibility this creates. If mood is contagious, then a leader's bad day is not a private event - which is the naturally-occurring-consequence argument applied to something most leaders think of as nobody's business.