Howstuffworks "Can people feel the pain of others?"

Perhaps you've seen someone bump their head or stub a toe and thought, "That had to hurt." Well, for some people, watching such an event actually does hurt. An unknown number of people have mirror-touch synesthesia, a condition that causes them to feel the touches that they see others receive. For example, if a mirror-touch synesthete sees someone touched on the cheek, she will feel as if her own cheek has been touched.

Photographer: Geotrac/Agency: Dreamstime
A mirror-touch synesthete
could feel pain from watching
someone receive a shot.

Like the name implies, there is a mirror effect involved. Say a mirror-touch synesthete is standing opposite someone. If the non-synesthete is hit in the right arm, the synesthete will feel it in her left arm. If the two are standing next to each other, contact with the non-synesthete's right arm will be felt in the synesthete's right arm.

Mirror-touch synesthesia is believed to be caused in part by mirror neurons, which produce an extremely developed sense of emotional empathy. Mirror neurons activate when an individual is performing an activity or, to a lesser extent, when an individual is watching someone perform an activity. People who have mirror-touch synesthesia have very active mirror neurons, meaning that the effect is greatly enhanced. They not only empathize with the pain of others -- often it feels to synesthetes as if the pain is also being applied to them as well.

Besides feeling the pain and touches of others, mirror-touch synesthetes often are very in touch with the feelings of others. Many claim no understanding of how people can laugh at others' misfortune, and action and horror movies are too unbearable to watch.

In 2003, Sarah Jane-Blakemore, a cognitive neuroscientist at University College London, was giving a lecture during which she mentioned that she had heard that some people could feel contact, such as a pinch, that they only observed. A 39-year-old woman at the event responded that she thought all people experienced that. For her entire life, this woman hadn't known that her mirror-touch synesthesia was unusual. Researchers later discovered that 11 of the woman's relatives had another type of synesthesia known as color-grapheme synesthesia.

Recent studies have shed more light on the phenomenon, including one published in the June 2007 issue of the journal "Nature Neuroscience." The study, performed by UCL researchers Jamie Ward and Michael Banissy, used brain scans, touch tests and questionnaires to detect mirror-touch synesthesia in 10 subjects. Brain scans showed hyperactivity in certain areas of the brain when mirror-touch synesthetes saw someone being touched. In touch tests, supposed mirror-touch synesthetes more often mistook observed touch for having the touch applied to themselves.

Further research about mirror-touch synesthesia could lead to discoveries about other empathy-related conditions such as schizophrenia, Asperger's syndrome and autism. For example, one symptom of autism is difficulty understanding the emotions of others. Learning why some people are highly sensitive to others' emotions could teach us more about those who aren't.

On the next page, we'll look at some other, better known types of synesthesia.

Other Types of Synesthesia

At its most basic level, synesthesia is a mixing of the senses. The term derives from the Greek words "syn" (together) and "aesthesia" (sensation). There are four main types of synesthesia, but even these can be difficult to separate or may be found together in one person.

Color-grapheme synesthesia - colors are associated with numbers, words or letters
Sound-color synesthesia - sounds are associated with colors
Word-taste synesthesia - words are associated with tastes
Taste-touch synesthesia - tastes are associated with physical sensations

In some cases, people also associate letters or words with colors and qualities. For example, the letter 'E' could be red, jagged and powerful. Some synesthetes also cite letters, months or days of the week as having three-dimensional qualities.

People with color-grapheme synesthesia associate colors with letters.

Despite various hypotheses, the causes of synesthesia are still unknown, though it's believed to have a hereditary association. Researchers believe that it's found in one out of every 100 or 200 people and is more common in women and left-handed people.

Men with morning sickness?
Not quite sympathy pains or mirror-touch synesthesia, a unique condition known as Couvade syndrome has afflicted some men with pregnant partners. These men have involuntarily experienced many of the symptoms of pregnancy -- food cravings, mood swings, cramps, enlarged stomachs, back ache, even morning sickness. Some symptoms persist until delivery -- one man even told the BBC that he thought his labor pains were more severe than his wife's! The symptoms usually go away after the baby is born, but men seem to have no control over them.

Like the mirror-touch synesthete who thought everyone was like her or people who go years without knowing that they are color-blind, some synesthetes may not even think they're different at all. That may especially be true for developmental synesthetes, those who have had synesthesia all their lives. Others can develop what's known as acquired synesthesia, which can be caused by drug use or brain injuries.

For those who have it, synesthesia can be useful. Synesthetic associations can boost memory abilities, and numerous artists, musicians, writers and other creative types have cited their synesthesia as an important component in their work. While some famous suspected synesthetes haven't been confirmed, here are some prominent people who have or had synesthesia:

Duke Ellington (jazz musician)
Richard Feynman (physicist, Nobel Prize winner)
David Hockney (painter)
Wassily Kandinsky (painter)
Franz Liszt (composer, conductor, pianist)
Vladimir Nabokov (writer, lepidopterist)
Nikolai Rimsky-Korsakov (composer)
Pharrell Williams (musician, producer)

For more information about synesthesia, the brain and other related topics, please check out the links on the next page.

Lots More Information