Exposure therapy can make this picture less scary — by altering your brainS

Exposure therapy is the practice of exposing people to things they fear in small doses, and it has helped vast numbers of people get over their phobias. But why? Now, a new study has shown that as little as a single session with a tarantula permanently alters the way an arachnophobe's brain works.

Photo of the Phidippus jumping spider by Alex Wild.

This research was undertaken on a group of 12 adults with severe arachnophobia — some so bad that they wouldn't leave the house for days if they thought a spider was around. Over the course of a two- or three-hour session, they were educated about tarantulas, and then slowly introduced to the arachnids. First they simply stood in the same room with one, then they slowly approached and touched the creature's terrarium. Eventually they graduated to touching the tarantula itself, first with an object, then through a glove, and eventually bare-handed.

Before the therapy, the patients underwent an fMRI, and the fear responses in their brains lit up when they looked at pictures of the spiders. After the therapy, those responses were significantly dampened. Even more impressive, that single session that they had with the spiders was enough that they were able to handle the tarantulas six months later, and still had reduced fear responses.

Also of note is that the long-term success of the treatment was to some degree indicated by the immediate results of the brain scan. Patients who had higher measurements of brain activity in response to visual perception of fearful stimuli had the lowest fear of spiders at the later date.

Before you try this at home, keep in mind, this was a slow, controlled exposure to an object of fear — not a Maury-style freakout.

This research does much to underscore the power of exposure therapy, but it also suffers some pretty big problems in terms of sample size. With just 12 patients, and a mean age of 22.3, it's a small and young group of people who underwent this. I'd love to see if the same holds true for a larger group with a more diverse age range, too.

Read the full scientific study via PNAS.