This is a process of expansion. There is more than one way to solve many problems. The students must give credence and thought to all levels, but work at the desirable level. The solution must be safe and cost effective with regards to time and effort. The need for a social structure that stresses cooperation must be expressed.
Social skills used are just as, or more, important than the thinking skills.
Without cooperation there is no success. Group size is critical - too small a group and the problems become too easy in many cases, too large and the problems become too difficult to accomplish. Let the students choose their own groups. Group size should be five to seven students. Six seems to be the ideal number for best results.