There are some within the field of behavior analysis who have suggested that the terms "positive" and "negative" constitute an unnecessary distinction in discussing reinforcement as it is often unclear whether stimuli are being removed or presented. For example, Iwata poses the question: "... is a change in temperature more accurately characterized by the presentation of cold (heat) or the removal of heat (cold)?" Thus, reinforcement could be conceptualized as a pre-change condition replaced by a post-change condition that reinforces the behavior that followed the change in stimulus conditions.