Olfactory research in humans has largely focused on odors perceived via sniffing, orthonasal olfaction, whereas odors perceived from the mouth, retronasal olfaction, are less well understood. Prior work on retronasally presented odors involves animal models and focus mainly on odor sensitivity, but little is known about retronasal olfactory perception and cognition in humans. In this study, we compared orthonasal and retronasal odor presentation routes to investigate differences in odor descriptions and evaluations. Thirty-six individuals participated in a within-subjects study using twelve odors (varying in pleasantness and edibility) in perceptual and semantic tasks. Orthonasal presentation was associated with a better ability to identify odors, and with more concrete (and source-based) language. Exploratory analyses revealed that whereas orthonasal odors were described with words that had visual associations, retronasal odors were described with words that had interoceptive associations. Interestingly, these route-dependent differences in descriptor usage were not explained by differences in sensitivity and intensity, suggesting instead a cognitive and linguistic processing difference between odors presented orthonasally and retronasally. Our results indicate that olfaction is, in fact, a dual sense, in which the routes change the perception of an odor.

中文翻译：

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气味的二元性：嗅觉和语言的路径依赖效应

人类的嗅觉研究主要集中在通过嗅觉感知到的气味，即鼻前嗅觉，而从口腔感知到的气味，鼻后嗅觉，人们不太了解。先前关于鼻后呈现气味的工作涉及动物模型，主要关注气味敏感性，但对人类的鼻后嗅觉感知和认知知之甚少。在这项研究中，我们比较了直鼻和鼻后气味呈现途径，以研究气味描述和评估的差异。36 名受试者参与了一项在感知和语义任务中使用 12 种气味（愉悦度和可食性不同）的受试者内研究。正鼻呈现与更好地识别气味的能力以及更具体（和基于来源）的语言有关。探索性分析表明，虽然正鼻气味是用具有视觉关联的词来描述的，但鼻后气味是用具有内感受性关联的词来描述的。有趣的是，描述符使用中这些依赖于路径的差异并不能用敏感性和强度的差异来解释，而是表明在直鼻和鼻后呈现的气味之间存在认知和语言处理差异。我们的研究结果表明，嗅觉实际上是一种双重意义，其中路径改变了对气味的感知。相反，这表明在直鼻和鼻后呈现的气味之间存在认知和语言处理差异。我们的研究结果表明，嗅觉实际上是一种双重意义，其中路径改变了对气味的感知。相反，这表明在直鼻和鼻后呈现的气味之间存在认知和语言处理差异。我们的研究结果表明，嗅觉实际上是一种双重意义，其中路径改变了对气味的感知。