That zero-sugar strawberry water that somehow still tastes sweet? Your brain is being tricked, and Swedish researchers now know exactly how it happens.
Scientists at Karolinska Institutet have discovered that the brain processes certain smells as actual tastes much earlier than previously understood, explaining why we can experience sweetness from aroma alone. The findings, published in Nature Communications, reveal a sophisticated neural deception occurring in the taste cortex itself.
When Noses Override Tongues
The research involved 25 healthy adults who underwent brain imaging while experiencing carefully controlled taste and smell combinations. Participants first learned to associate specific aromas with sweet or savory flavors through repeated exposure to taste-smell pairings. Then, researchers used functional magnetic resonance imaging to monitor brain activity as participants received either pure tastes without smell or pure aromas without taste.
“We saw that the taste cortex reacts to taste-associated aromas as if they were real tastes,” explains lead author Putu Agus Khorisantono, researcher at the Department of Clinical Neuroscience.
The team trained machine learning algorithms to recognize brain activity patterns for sweet and savory tastes, then tested whether the same neural signatures appeared when participants only smelled the associated aromas. The results were striking: smell-based “tastes” activated identical regions of the brain’s primary taste cortex, the insula, producing remarkably similar neural patterns to actual tastes.
This crossmodal trickery occurred specifically in the dysgranular and agranular regions of the insula, areas known to integrate different sensory signals. These brain regions showed overlapping representations for both real tastes and their associated aromas, creating what researchers term a “shared flavor-specific neural code.”
The Supermarket Psychology Connection
The implications extend far beyond laboratory curiosity. This neural mechanism may help explain modern eating behaviors, from the appeal of artificially flavored beverages to the powerful influence of food aromas on consumption choices.
“This shows that the brain does not process taste and smell separately, but rather creates a joint representation of the flavor experience in the taste cortex,” says senior researcher Janina Seubert.
The research team found that this integration happens much earlier in neural processing than the established model suggested. Previously, scientists believed taste and smell signals traveled separately to higher brain regions before combining in the orbitofrontal cortex, which handles complex decision-making about food. Instead, the integration begins immediately in the primary taste cortex.
Interestingly, the study also revealed that these taste-smell representations aren’t static. Neural patterns for the same flavors changed between different testing days, suggesting our brains continuously update these sensory maps through experience.
The researchers used sophisticated controls to ensure their findings weren’t simply reflecting pleasant versus unpleasant sensations. Participants’ individual preferences for sweet or savory stimuli didn’t correlate with the crossmodal brain activity, confirming that the effect represented genuine taste-smell integration rather than simple hedonic responses.
Looking ahead, the team plans to investigate whether similar neural deception occurs with external smells encountered in daily life. They want to determine if walking past a bakery could actually trigger “sweet” neural responses in the taste cortex, potentially influencing food choices before conscious decision-making even begins.
The findings offer new insights into how flavor perception shapes eating behaviors and may inform approaches to managing food cravings and dietary choices. Understanding this neural sleight of hand could prove valuable for both food industry applications and public health strategies aimed at promoting healthier consumption patterns.
Nature Communications: 10.1038/s41467-025-63803-6
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