Grocery Bag as an Indicator

In HBS Working Knowledge: An interesting example. But also an example of lack of actual causality in an indicator as well.  Still useful for understanding the multiple reasons a person comes to a conclusion.  " ... "I'm of the mindset that it's useful to know the kinds of things that influence your own behavior," Karmarkar says. "If you're trying to maintain a strict diet, maybe you can recognize the bag's influence, and consciously fill the desire to treat yourself in another way that doesn't interfere with your goals. Maybe you can treat yourself to an extra half hour of sleep." .... "