Preliminary findings on the influence of the presence of others' eyes on food intake.

Background: The presence of others' eyes has been shown to influence food evaluation. Aim: The purpose of the present study was to investigate whether the presence of others' gaze would lead to a reduction in food intake in accordance with social norms. Methods: In this study, we enlisted the participation of 30 volunteers. During the experiment, participants had the opportunity to consume noodles freely as much as they wanted while viewing one of the three images: (1) featuring a person with open eyes (Open condition), (2) depicting a person with closed eyes (Closed condition), and (3) displaying an image devoid of a person (None condition). Results: Food consumption in each condition was 460.00 ± 20.97 g for the Open condition, 515.57 ± 22.97 g in the Closed condition, and 505.03 ± 21.05 g in None condition. The condition had a statistically significant main effect (F = 4.656, p = .013). The Least-Square means analysis revealed that food consumption in the Open condition was significantly lower than in the other two conditions (Closed and None conditions) (Closed - Open: t = 2.872 [95% CI: 16.844-94.289], p = .006; None - Open: t = 2.328 [95% CI: 6.311-83.756], p = .023). There was no significant difference in food consumption between the Closed and None conditions (Closed - None: t = 0.545 [95% CI: -28.189-49.256], p = .588). Conclusion: The results of the present study suggest that the presence of others' eyes would reduce food intake in accordance with social norms.