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Most people living with chronic pain can tell you that pain drains their memory capacity. Indeed, it’s well demonstrated that pain affects your ability to encode information—to lay down new memories.
Would you believe that pain has the ability to alter your recollections of life events, essentially ‘rewriting’ your history? While perhaps not quite as dramatic as that, new research suggests that experiencing fear and unpleasant physical sensations can alter the content of your memories.
In recent work published in Nature, Dr. Phelps and colleagues describe their experiment whereby they had participants perform tasks that involved classifying visual images into one of two categories. Participants first performed the classification task. About 5 minutes later, half of the participants performed the same task while given “highly unpleasant” electric shocks in a form of fear conditioning. The researchers tested how the conditioning impacted memory for the classification task.
Six hours and 24 hours later, participants were shown images again and were asked to identify whether or not they had classified each image previously. While there were no differences in recall at 6 hours, at 24 hours differences emerged. Positive recall of images that were similar to the ones paired with electric shocks was greater than for images not associated with shocks. In other words, there was greater recall bias for visual content that was similar to what one saw at the time of the unpleasant shock.
It is not known how much of the recall bias was due to unpleasant sensation, to fear conditioning, or the combination of the two. Given that there were no differences in recall at 6 hours, the effect does not appear to be a bias related to the encoding of information. Rather, the researchers write that “memories for neutral information can be enhanced by a future emotional event that involves conceptually related material.”
In other words, what we experience today can impact our memories of similar events that happened yesterday. Our present-moment experience is so powerful it may reinforce or ‘overwrite’ our memory of a past experience.
Now let’s envision the possibility that the phenomenon exists in the POSITIVE direction: That we have the capacity to reinforce and re-code memories to have greater levels of happiness, joy, and physical comfort. These are the experiments I would love to see. In the meantime, enjoy your own positive experiments.
