Objective and purpose: Although there is increasing interest in how environmental factors influence food intake, there are mixed results and misunderstandings of how proximity and visibility influence consumption volume and contribute to obesity. The objective of this paper is to examine two questions: first, how does the proximity and salience of a food influence consumption volume? Second, are proximate foods consumed more frequently because they are proximate, or are they consumed more frequently because people lose track of how much they eat?
Research methods and procedures: The 4-week study involved the chocolate candy consumption of 40 adult secretaries. The study utilized a 2 x 2 within-subject design where candy proximity was crossed with visibility. Proximity was manipulated by placing the chocolates on the desk of the participant or 2 m from the desk. Visibility was manipulated by placing the chocolates in covered bowls that were either clear or opaque. Chocolates were replenished each evening, and placement conditions were rotated every Monday. Daily consumption was noted and follow-up questionnaires were distributed and analyzed.
Results: There were main effects for both proximity and visibility. People ate an average of 2.2 more candies each day when they were visible, and 1.8 candies more when they were proximately placed on their desk vs 2 m away. It is important to note, however, that there was a significant tendency for participants to consistently underestimate their daily consumption of proximately placed candies (-0.9) and overestimate their daily consumption of less proximately placed candies (+0.5).
Discussion: These results show that the proximity and visibility of a food can consistently increase an adult's consumption of it. In addition, these results suggest that people may be biased to overestimate the consumption of foods that are less proximate, and to underestimate those that are more proximate. Knowing about these deviation tendencies is important for those attempting effectively monitor their consumption of fat and sugar.