The phrase "forgive and forget" may be scientifically meaningful.
Researchers from the University of St. Andrews found that once a person was able to forgive a past transgression against him, he was also more likely to forget the details of what happened.
"It is well established that learning to forgive others can have positive benefits for an individual's physical and mental health," Saima Noreen, lead author of the study, said in a statement. "The ability to forget upsetting memories may provide an effective coping strategy that enables people to move on with their lives."
The reason these two abilities are closely linked may be because they are both facilitated by the same underlying cognitive function. The process of forgiving is a function of executive control—the major network of cognitive mechanisms that allows people to regulate emotions, empathize, and connect memory to present experience, among other features. Executive control is what allows the aggrieved to overcome negative emotions and feelings of retribution. And that same ability allows us to erase details from our memories when we're motivated to do so, theorized the research team.
As part of the study, participants were asked to read 40 different hypothetical stories of theft, infidelity, slander, and other difficult-to-forgive actions. They were then asked to determine if they would be able to forgive these wrongdoings if they had been the victims. After a couple of weeks, the participants returned to read some of the scenarios again, but this time they were also subject to a common memory research experiment, in which each scenario was paired with a red or green "cue word." Participants were instructed to remember scenarios associated with green cue words and told to forget those associated with a red cue word.
The researchers found that participants who were instructed to forget a scenario were much more likely to have done so if it were a scenario they had initially been able to forgive. What's more, those who had not forgiven the scenario had no ability to forget the details of the theoretical wrongdoing.
Forgiveness is, of course, good for one's psychic well-being, but it also may provide a physical health benefit. Past research shows that forgiveness lowers blood pressure (for both victim and perpetrator), is associated with a drop in the stress hormone cortisol, and even contributes to less back pain.