Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
Br J Nutr. 2012 Feb;107(4):588-94. doi: 10.1017/S0007114511003278. Epub 2011 Jul 5.
Portion size and the intake of others have been found to influence people's food intake. No study, however, has tested the potential influences of both types of situational norms on intake during the same eating occasion. We experimentally tested the effects of manipulating portion size and the intake of others on young women's meal intake during a 20 min eating opportunity. An experimental design with a three (confederate's intake: small, standard, large) by two (portion size: small, standard) between-participants design was used. A total of eighty-five young women participated. Portion size and the confederate's intake both influenced young women's intake. Participants consumed more when offered a larger portion than when offered a smaller portion, and they also ate more when their eating companion ate more. The present results indicate that the effects of portion size and the intake of others were independent but additive. Thus, both types of situational norms might independently guide an individual's intake during a single eating occasion.
份量大小和他人的进食量已被发现会影响人们的食物摄入量。然而，尚无研究测试在同一进食期间这两种情境规范对摄入量的潜在影响。我们通过实验测试了在 20 分钟的进食机会中操纵份量大小和他人进食量对年轻女性进餐量的影响。采用了三（同伴的摄入量：小、中、大）×二（份量大小：小、中）的参与者间实验设计。共有 85 名年轻女性参与了实验。份量大小和同伴的进食量都影响了年轻女性的摄入量。与提供小份量相比，参与者在提供大份量时摄入更多，而当他们的饮食同伴吃得更多时，他们也吃得更多。本研究结果表明，份量大小和他人进食量的影响是独立但可累加的。因此，这两种情境规范可能在单一进食期间独立地指导个体的摄入量。
