If you play sounds of many different frequencies at the same time, they combine to produce neutral “white noise.” Similarly, if you combine all the colours of the rainbow together it forms “white light”.
Neuroscientists say they have created an analogous generic scent by blending odors. Such “olfactory white” might rarely, if ever, be found in nature, but it could prove useful in research, other scientists say.
Using just a few hundred types of biochemical receptors, each of which respond to just a few odorants, the human nose can distinguish thousands of different odors. Yet humans can’t easily identify the individual components of a mixture, even when they can identify the odors alone. When various blends made up of a large number of odors all begin to smell the same—even when the blends share no common components.
Researchers have found that white noise is a useful stimulus in experiments to probe auditory responses and scientists probing the human sense of smell might find similar uses for olfactory white. Learn more here.