This is actually interesting research, but I do feel that too much is made of the fact that we see differences in brain activity when different groups react differently to stimuli. Everything you think and feel are networks firing in the brain. When research looking at the patterns of brain activity is reported, however, it often makes it sound like it’s surprising that such differences are “in the brain,” as if this makes the differences more biological or fundamental.

In any case, what this recent study looked at was 23 volunteers (12 believers and 11 skeptics) who were separated into their respective groups by a questionnaire – do you think that psychics can predict the future, etc. They “first imagined themselves in critical life situations (e.g. problems in intimate relationships) and then watched emotionally charged pictures of lifeless objects and scenery (e.g. two red cherries bound together).”

The researchers found that those who scored as a believer on the screening test were twice as likely as those who scored as skeptics to find meaning in the images – some sign predicting how the situation would turn out. That is not surprising, and in a way just validates the screening test (it predicted a later response).

The primary purpose of the study, however, was to look at brain activity with fMRI to see if there were any differences in brain activity. All subjects displayed activity in their left inferior frontal gyrus, which may represent seeing meaning in the images. The skeptics, however, also displayed greater activity in their right inferior frontal gyrus; an area that previous research indicates is associated with inhibitory control.

This suggests (if the results are valid – it is a small study) that everyone instinctively will see portents and signs in provocative imagery (especially if primed with an emotional situation), but that those who tend to be skeptical have a greater ability to inhibit that instinct.

Inhibitory control is an important cognitive function. Generally speaking, activity in various parts of the brain, including more primitive and emotional parts, is filtered through the most recently evolved part of our brains, the neocortex (frontal lobes) which strategically inhibits the more basic activity as part of long term planning, social behavior, and other functions referred to as “executive function.”

Someone, therefore, who appears cool and rational may have just as much of an emotional cauldron boiling beneath the surface, but has strong inhibitory control. Someone who is impulsive and glib may simply have a relative lack of inhibitory control.

In fact there is a known neurological syndrome of “disinhibition” which can be caused by damage to the frontal lobes (this is often in the context of a car accident where the forehead hits the windshield).

Attention deficit hyperactivity disorder (ADHD) clinically is a disorder of executive function, and is associated with decreased activity in the frontal lobes.

All of this fits well with how skeptics often understand the process of scientific skepticism. People have a tendency to be compelled by emotional narratives, and to see patterns and signs in random stimuli. Skepticism, in part, is not accepting such stories or apparent patterns at face value, but evaluating them with an objective process to differentiate real patterns from illusory ones.

In this way skepticism is often a negative or inhibitory process – sifting out the chaff from the wheat. It is therefore not surprising that in a task that challenges one’s skepticism, the primary difference between skeptics and believers is in relative inhibitory control.

Of course, I don’t know if the pattern of results seen in this study is reliable. It is one small study, and fMRI studies can be technically very tricky to do well. I would love to see it replicated with a larger sample and more variables.


Steven Novella, M.D. is the JREF's Senior Fellow and Director of the JREF’s Science-Based Medicine project.