on their way to the lab, Ps pass a workman (C) standing on the ladder
IV1: in the lab, half of PS work with a partner (a passive C) on a task, the rest work alone
then PS hear the ladder fall, a thud, and the man groan in pain
IV2: Participants (nurses or not)
DV: who helps?
Results: the nurses helped, regardless of condition, non-nurses were more likely to help if they worked alone