Japanese scientists have found that the brain perceives unpleasant odors faster than pleasant ones. They assumed with
To conduct experiments, researchersdeveloped a special device capable of accurately transmitting smell into the human nasal cavity. Participants had to rate the properties of ten different odors, while their brain signals were recorded by electroencephalography (EEG). The data was then processed using machine learning.
It turned out that the brain detected odors even beforehow a person was aware of them. In addition, the idea of the unpleasantness of the smell appeared in the brain earlier than the pleasantness. Thus, the brain recognized the smell of rot or rotten meat within 300 milliseconds after its appearance. But the smells of flowers or fruits were recognized after 500 milliseconds.
Scientists have suggested that such a feature arose in the process of evolution as an early warning system for potential dangers.