Kennedy-Hagan 2011

Research paper

Kennedy-Hagan K, Painter JE, Honselman C, Halvorson A, Rhodes K, Skwir K. The effect of pistachio shells as a visual cue in reducing caloric consumption. Appetite. 2011;57(2):418-420.

Why we cite it

Tests a specific visual feedback mechanism: whether seeing accumulated food waste (pistachio shells) helps people self-regulate intake. Found an 18% calorie reduction when shells remained visible — without affecting satisfaction. Important for environment design because it shows that visible consumption evidence serves as a non-conscious portion control cue. Note: often conflated with the companion study cpi10 (Honselman 2011) which tests a different mechanism (in-shell vs shelled, 41% reduction) — see notes.txt for the discrepancy.