Human olfactory psychophysics

Of all the senses, smell is the least understood. Despite centuries of investigation, science can still offer no satisfying theory for why a particular substance smells the way it does. Nor do we understand in any detail how we are able to distinguish the smell of a peach from that of an apricot, or how a particular smell can trigger longforgotten memories of a distant time or place. Human olfactory psychophysics, the study of how humans perceive odors, is possible because humans have acquired language. Human subjects can report directly if something smells, characterize the smell, or decide if two smells are distinguishable. Answers to these simple questions have the potential to provide insight into important questions: What (if any) is the relationship between the chemical structure of an odor and its perceived smell? What types of olfactory stimuli can be discriminated, and how is this accomplished in the nose and the brain? How does experience modulate our perception of odorants? There are of course many things that cannot be done in humans, for instance genetic manipulation and electrophysiology, but these types of approaches are successfully used in animal models.