Take artist Concetta Antico, for example. She’s one of a few individuals confirmed to have tetrachromacy – a condition caused by a gene that alters how a person’s retinas develop. The average human possesses three types of cone-shaped cells that determine color perception. Concetta, however, was confirmed by genetic tests to have a fourth type, giving her the ability to see a much wider spectrum of colors than average.
Instead of having intensified vision or smell, some people perceive unique combinations of the senses. The phenomenon known as synesthesia can cause different senses to overlap. Individuals with various types of synesthesia report being able to taste words or to see the colors of musical notes. Some people experience multiple forms of synesthesia at once, although researchers are still uncertain of exactly how unusual the condition is and what causes it. One theory suggests that synesthetes may be equipped with extra neural connections that lead to a collapse of boundaries between senses over time.
Characters with extreme senses fill the pages of comic books and science fiction novels, but there are a number of real disorders that can cause heightened sensitivity to certain stimuli. Sometimes, such as in the case of sensory processing disorder, it can become a burden by causing the body to over-respond to everyday sensations of touch. Others, like hyperosmia, intensify odors and occasionally taste. The rare condition of hyperacusis amplifies an individual’s auditory perception, making noises of a certain frequency seem unbearably loud.
There’s evidence that the senses we’re born with can be willfully changed over time as well. Studies show that the human sense of smell is actually keener than you might believe, and can be either strengthened or blunted through training. It has long been postulated that people who have lost one sense are capable of further developing others to compensate. But if that’s the case, do these new skills have to be learned, or does an increase in one area of sensory perception occur naturally?
Recent studies support the theory that the brain can actually rewire itself to dedicate more space to a particular sense if another is compromised. The brain of a deaf individual can rely on the areas meant to interpret sound for other uses, such as sight, smell or touch. Known as “cross-modal neuroplasticity,” this line of research has the potential to shed light on how the human brain organizes itself and processes outside sensations.
Whatever the causes, the ways people with extreme senses experience the world are fascinating – and showcase the untapped power of the human brain.