Researchers from a UK university conducted a study to explore how our sense of smell can influence color perception in the visual system. They also noted that many people commonly associate certain odors with specific colors, a link that can shape how we experience color itself.
In the experiment, twenty-four volunteers aged between 20 and 57 visited a quiet room designed to minimize sensory cues. Participants entered one at a time and sat facing a screen, with instructions to avoid using any fragrances and to refrain from applying deodorants or perfumes before taking part. The room contained no distracting noises or ambient odors that could bias perception.
As each person entered, one of six scents—caramel, cherry, coffee, lemon, mint, or water—was dispersed into the air with a small diffuser. Immediately afterward, a square of a randomly selected color appeared on the screen. The task for the volunteer was to adjust the square to a neutral gray using two sliders. The same sequence was repeated six times for each scent, with a fresh scent introduced before the next round started.
Results revealed that the presence of different odors caused participants to over-adjust the sliders, and many could not render the square a true neutral gray. For instance, when the scent of coffee wafted through the room, participants tended to choose a gray shade with a hint of brown. Likewise, after detecting caramel, several volunteers moved the sliders toward a gray with a slight blue tint, even though the goal was pure gray.
Notably, the mint scent produced more varied responses among individuals, and in several cases, participants did not settle on the same gray shade. The water scent, however, was an exception: nearly all participants managed to achieve a neutral gray, suggesting a different interaction between this odor and visual color processing.
The authors interpreted these observations as evidence that color perception is not solely determined by the eyes and the brain’s processing of light. Instead, the senses of smell and perhaps even memory and emotion linked to specific scents can subtly bias color judgments. While the exact neural mechanisms remain unclear, the study points to a cross-modal influence where olfactory input can alter how color is experienced on the screen.
Looking ahead, researchers plan to pursue further experiments to map how different odors influence color perception under varied lighting, backgrounds, and task demands. Such work could shed light on how sensory integration operates in everyday life and how smells might bias visual decisions in contexts ranging from design to safety-critical monitoring.
Overall, the study adds to a growing body of evidence that sensory experiences are interconnected in surprising ways. It suggests that our world of colors is shaped not only by what our eyes see but also by what our noses sense, offering intriguing implications for fields that rely on precise color judgments and perceptual consistency.