Which researcher developed the categorizaiton scheme for five categories of play varying in social complexity?

Allport's Proprium

What will be an ideal response?

During phase one of the 1966 Robbers Cave study, the separate groups developed group membership and solidarity. During phase two:

a. the boys began a series of cooperative events across the groups. b. the boys began a series of competitive events between the groups. c. hostility between the two groups of boys decreased. d. the groups failed to illustrate the ingroup-outgroup bias expected by Sherif.