Intrusions into waiting lines: Does the queue constitute a social system?

Four experiments tested whether a waiting line should be viewed as a social system with norms, roles, and obligations for queuers or whether behavior in a queue can be explained solely by individuals' personal interests and cost versus benefit calculations. The 1st 3 studies demonstrated that Ss were more likely to respond to an intruder than to aservice provider who interrupts the service for a specific amount of time even though waiting costs were manipulated to be identical in both situations