Olfactory perception is malleable and easily modulated by top-down processes such as those induced by visual and verbal information. A classic example of this is olfactory illusions where the perceived pleasantness of an odor is manipulated by the valence of a verbal label that is either visually or auditorily presented together with the odor. The mechanism behind this illusion is still unknown, and it is not clear if it is driven only by verbal information or if there is an interaction between language functions and visual mental imagery processes. One way to test this directly is to study early blind individuals who have little or no experience of visual information or visual mental imagery. Here, we did this by testing early blind, late blind, and sighted individuals in a classical paradigm where odors were presented with negative, neutral, and positive labels via speech. In contrast to our hypothesis—that the lack of visual imagery would render early blind individuals less susceptible to the olfactory illusion—early and late blind participants showed more amplified illusions than sighted. These findings demonstrate that the general mechanism underlying verbally induced olfactory illusions is not caused by visual processing and visual mental imagery per se.

嗅觉是可塑的，很容易通过自上而下的过程（例如由视觉和言语信息引起的过程）进行调节。一个典型的例子是嗅觉错觉，其中感知到的气味的愉悦感是由与气味一起在视觉或听觉上呈现的言语标签的效价操纵的。这种错觉背后的机制仍不清楚，也不清楚它是否仅由言语信息驱动，或者语言功能和视觉心理意象过程之间是否存在相互作用。直接测试这一点的一种方法是研究那些很少或根本没有视觉信息或视觉心理意象经验的早期盲人。在这里，我们通过在经典范式中测试早期失明、晚期失明和视力正常的个体来做到这一点，其中通过言语向气味提供负面、中性和正面标签。与我们的假设相反——视觉意象的缺乏会使早期失明的个体不易受到嗅觉错觉的影响——早期和晚期失明的参与者表现出比视力正常的人更放大的错觉。这些发现表明，言语引起的嗅觉错觉的一般机制并不是由视觉处理和视觉心理意象本身引起的。