Self-control may weaken memory

Our ability to inhibit an action or override an inclination while doing another task may affect memory and attention, suggests new research.

The study by researchers from Duke University in North Carolina, US, found that inhibiting response or cancelling an intended action suppresses activities in areas of brain linked to memory.

The findings may eventually lead to new therapies for disorders characterised by difficulty inhibiting actions, such as attention deficit hyperactivity disorder (ADHD) and addiction.

In an earlier study, the researchers tested how response inhibition affected memory.

In that study, participants completed a computer-based task in which they were asked to press a button if they saw a male face but withhold a response if they saw a female face. (Some participants were asked to do the reverse.) They looked at a total of 120 different faces.

After five minutes of a filler task that had nothing to do with faces, the participants were then given a surprise memory test in which they viewed faces and were asked to indicate whether a face was new or familiar from the earlier task.

"We didn't really know which way that would go," said one of the researchers Tobias Egner, assistant professor of psychology and neuroscience at Duke.

"You could argue quite easily that cancelling a response to a stimulus might actually make that stimulus more memorable," Egner noted.

However, they found the exact opposite: Memory was a little worse on the faces for which participants had to inhibit their responses.

In the latest study, the researchers saw the same results.

One potential reason people were forgetting the faces was that withholding a response was siphoning off their attention.

The researchers found that brain areas that are known to be active when a person is committing something to memory were suppressed on those trials in which the participants had to inhibit their responses strongly.

The study was published in the Journal of Neuroscience.