Fontana Lara, Albayay Javier, Fernández-Prieto Irune, Zampini Massimiliano
Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.
Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
Q J Exp Psychol (Hove). 2023 Jun;76(6):1209-1219. doi: 10.1177/17470218221115046. Epub 2022 Aug 8.
Olfactory perception can be modulated by the repeated exposure to odours. Olfactory habituation is a reduced behavioural response to repetitive stimulation. Edibility is considered an important top-down feature that can affect olfactory perception, but whether it could modulate olfactory habituation when food or nonfood odours are repeatedly smelled remains unclear. Indeed, due to their ecological salience, food odours attract attention automatically which might slow down habituation. This registered report aimed to determine whether olfactory habituation shows a different pattern when participants are presented with food or nonfood odours. In a within-subject design, 50 participants were tested under satiated and fasted states in separated experimental sessions. In each session, participants were exposed to the same food and nonfood odour in different blocks of 20 trials each. Participants rated the perceived odour intensity and pleasantness after each trial. We used an intermittent odour presentation to reduce olfactory fatigue while capitalising on the effect of cognitive states on habituation. Linear mixed-effects models showed that the perceived odour intensity decreased over time only for nonfood odours. Conversely, the perceived odour pleasantness decreased significantly more across trials for food odours. These effects were retrieved regardless of the participant's hunger state. Our results are in line with the olfactory-specific satiety theory which posits a specific decrease in the perceived pleasantness of food odours, without changes in the perceived odour intensity. In short, our findings indicate that perceived odour edibility modulates olfactory habituation, extending the previous literature on the impact of top-down factors on olfactory perception.
嗅觉感知可通过反复接触气味来调节。嗅觉习惯化是对重复刺激的行为反应减弱。可食用性被认为是一种重要的自上而下的特征，能够影响嗅觉感知，但当反复闻食物或非食物气味时，它是否能调节嗅觉习惯化仍不清楚。实际上，由于食物气味具有生态显著性，它们会自动吸引注意力，这可能会减缓习惯化进程。本预注册报告旨在确定当向参与者呈现食物或非食物气味时，嗅觉习惯化是否呈现出不同的模式。在一项被试内设计中，50名参与者在饱足和禁食状态下分别进行实验。在每个实验环节中，参与者在不同的20次试验组块中接触相同的食物和非食物气味。每次试验后，参与者对感知到的气味强度和愉悦度进行评分。我们采用间歇性气味呈现方式来减少嗅觉疲劳，同时利用认知状态对习惯化的影响。线性混合效应模型显示，仅对于非食物气味，感知到的气味强度随时间下降。相反，对于食物气味，在多次试验中感知到的气味愉悦度下降得更为显著。无论参与者的饥饿状态如何，都能观察到这些效应。我们的结果与嗅觉特异性饱腹感理论一致，该理论认为食物气味的感知愉悦度会有特定下降，而感知到的气味强度不变。简而言之，我们的研究结果表明，感知到的气味可食用性会调节嗅觉习惯化，扩展了先前关于自上而下因素对嗅觉感知影响的文献。
