From a study in the Journal of Applied Behavior Analysis:
We investigated the effects of competitive and cooperative games on aggressive and cooperative behaviors of 70 children (4 to 5 years old) from four classes in three preschools. The experimental design induded both multiple baseline and reversal components. Behaviors were measured during game conditions and in subsequent free-play periods. Results showed that cooperative behavior increased and aggression decreased during cooperative games; conversely, competitive games were followed by increases in aggressive behavior and decreases in cooperative behavior. Similar effects were also found during free-play periods…

Cooperative board games used in the study included Max®, Harvest Time®, Granny’s House®, and Sleeping Grump®. Cooperative physical activities included musical chairs, balance activities, freeze-defreeze tag, devine, half-a-heart, cooperative musical hugs, and bean bag freeze…

The key conclusions of the study are that cooperative games produce less aggressive behaviours during and after play and, that as a result, they require less direct supervision by the teachers, win/win. It could be argued that they would pay for themselves in saved teacher work-hours.

Click to read the full paper here Journal of Applied Behavior Analysis (Fall 1994)