A:In an escape contingency, the aversive stimulus is present as an EO prior to the occurrence of the target behavior. The target behavior then terminates that EO. For example, if it is raining outside and raindrops are falling on your head, putting up an umbrella terminates raindrops falling on your head. In an avoidance contingency, the aversive stimulus is NOT present as an EO prior to the occurrence of the target behavior. However, it is "threatened." By engaging in the target behavior, the individual avoids the presentation of that aversive stimulus. For example, if you are inside and you are planning to go outside, but you see that it is raining, you might put up your umbrella before you walk out the door to avoid having raindrops fall on your head. Both of these examples are negative reinforcement contingencies, but the first is an example of an escape contingency and the second is an example of an avoidance contingency.