High-Probability Requests and Demand Fading

Understanding High-Probability Request Sequences (Behavioral Momentum)

A high-probability request sequence is an antecedent intervention used to increase the likelihood that a learner follows an instruction they have followed at a low rate in the relevant setting; that instruction is not necessarily less preferred. In applied behavior analysis, high-probability request sequences are also commonly referred to as behavioral momentum. Because this intervention is applied before problem behavior occurs, it is categorized as an antecedent strategy. A supervisor may include a high-probability request sequence in a behavior intervention plan to increase instruction following, including when instructional demands are associated with escape-maintained behavior.

To understand how this procedure functions, technicians must know the difference between high-probability and low-probability requests. A high-probability request is an instruction the learner has followed at a high rate in the relevant setting. These requests are selected because the learner is likely to follow them, often because they are easy or familiar. High-probability requests should be actions the learner can do and has a history of doing when asked; however, they do not have to be formally mastered skills. In contrast, a low-probability request is an instruction the learner has followed at a low rate in the relevant setting.

In practice, the RBT presents several requests the learner is likely to follow, then promptly presents the target request the learner has been less likely to follow, as specified in the written plan. For example, if a learner usually follows requests to clap hands, touch their nose, and give a high-five but is less likely to open a workbook when asked, those three easy actions could form a high-probability sequence presented right before the workbook request. By establishing a pattern of responding to familiar tasks, the technician builds momentum toward completing the target request.