This research proposes that motivation fluctuates in ways that are not accounted for by these theories and the scales based on them. The Elaborated Intrusion Theory of Desire (EI Theory) [10] provides an alternative framework for understanding motivated behaviour by focusing on motivational states over time. Desire for a goal is seen as an episodic experience involving cognitive elaboration of goal-related thoughts that in turn are determined by external cues, competing cognitive activities and conflicting goals. EI theory was initially advanced in the context of psychoactive substance use [10, 17], but has been applied to a variety of other reward targets including food [18–20], and to behaviours such as physical activity.