Self-control eats your memory.

The Guardian reveals how exerting the willpower not to eat that next donut actually lowers your ability to remember things clearly:

In the lab, self-control – or response inhibition, as neuroscientists call it – is often tested with the ‘Go/ no–go’ procedure. This typically involves showing participants a stream of sensory cues, and to respond to most of them by performing a simple action, such as pressing a button. But a small subset of the cues are slightly different from the rest, and when these appear, they are supposed to withhold their usual response and refrain from pressing the button. The number of times a participant incorrectly presses the button on these “no-go” trials is thus taken as a measure of their self-control.

Earlier this year, Yu-Chin Chiu and Tobias Egner of Duke University in North Carolina reported that response inhibition impairs memory encoding. They asked volunteers to perform a ‘Go/ no–go’ task, using photographs of faces as cues, and then tested their ability to recognise the faces used in the experiment. They found that the participants’ memory for the faces they saw during the “no–go” trials was far worse than for the rest, and therefore hypothesized that response inhibition competes with memory encoding for common attentional resources.

To test this idea, Chiu and Egner repeated the experiment using functional magnetic resonance imaging (fMRI). They recruited 24 additional participants, and asked them to perform a ‘Go/ no–go’ task while having their brains scanned. Once again, they used photographs of faces as visual cues, and tested the participants’ ability to recognise them shortly afterwards.

This confirmed their earlier findings that the participants’ memory was worse for the ‘no–go’ than for ‘Go’ faces.

These findings strongly suggest that self-control and memory encoding share common brain structures and mechanisms, and compete with each other for them, and so support Chiu and Egner’s “inhibition-induced forgetting” hypothesis.