-boys were asked to rate 12 paintings by abstract artists klee and kandinsky and were not aware of who painted what during the experiment.
-randomly allocated to 1 of 2 grps and were told they had preferred either klee or kandinsky
-each boy was then given task to award points to two other boys: one from his group and one from the other group
-the only information they were given was their code numbers and their group names
-point allocation system 1: sum of both scores must add up to 15
-ponit allocation system 2 was manipulated by tajfel: he made it to that if a klee member chose high points for another, it would give higher points to the out-group. if they chose a medium number, each grp would get the same points and if they chose a low number the other grp would only get one point