"[We] explore the theoretical conditions that facilitate the selection of goal-incongruent actions. We propose that the consequence of an initial goal pursuit on subsequent actions is different depending on whether the individual focuses on goal progress or on goal commitment," explain Ayelet Fishbach (U. Chicago) and Ravi Dhar (Yale).
Through four separate experiments, including one that asked dieters to choose between apples and chocolate bars, the authors sought to determine the effect of goals on choice. They found that progress towards a goal frequently liberates people to pursue another, incompatible goal. Furthermore, simply making plans to work towards a goal can lead to the immediate satisfaction of an conflicting desire.
"If people simultaneously hold multiple goals, an account of consumer behavior needs to address the manner in which pursuing each of these goals may justify the subsequent pursuit of another, potentially conflicting goal," write Fishbach and Dhar.
Fishbach, Ayelet and Ravi Dhar. "Goals as Excuses or Guides: The Liberating Effect of Perceived Goal Progress on Choice." Journal of Consumer Research, Dec 2005.