“…Weisman and Litner (1971) concluded that inhibition brought about by a stimulus is, in part, a function of the inhibition elicited by another stimulus present in the situation. Moreover, Cändido et al (1989), using a one-way response, found that the supposed reinforcing power of the time spent in the safety compartment depended on the time spent in the danger compartment (see also Denny, 1971;Modaresi, 1975Modaresi, , 1984. It may be that the reinforcing power of feedback does not depend on its absolute duration, but rather on its duration in relation to the danger-free period that follows-that is, the time without feedback before the start of the waming signal.…”