# Boundary In the property law context, a boundary is a line on the surface of the earth described by compass bearings and distances relative to a landmark. In behavioral psychology, a boundary is a non-moralistic statement of the conditions under which a person will or will not continue to engage in a particular interaction. It is non-moralistic because it is not a declaration of what the other person should do, but of what the boundary-setter will do in response to specific behaviors. A boundary in this sense is a contingency statement: if a given stimulus occurs, a given response will follow.