The nose is hungrier than the eyes.

Vision and olfaction are the main sensory channels for appraising food prior to eating. Motivational models often assume that these sensory channels function in an equivalent manner. We tested this notion by asking participants to rate their desire for some snacks only via smell and others only via vision. In the next phase, participants consumed a small sample of every snack, now with all of the senses available, rating liking and desire for more. After consuming a meal, participants repeated the desire/liking test. Sensing via olfaction, relative to vision, led to greater desire ratings irrespective of state. When hungry, judgments of liking and desire for more were higher for foods that were initially smelled relative to those that were initially seen. Across the meal, visually based desire ratings declined more than those based on smell, relative to ratings made when the snacks were tasted. Together, this suggests motivational equivalence does not hold for olfaction and vision. We suggest this may be due to a greater reliance on memory for generating visually based desire.