Sound signals during sleep can help people forget specific memories

Overview: Previous research has found that sound cues played during sleep can improve a person’s memory. A new study reports that sound signals during sleep may also help weaken intrusive and traumatic memories. Researchers say sound signals can be used during sleep to both increase and decrease the ability to recall specific memories.

Source: York University

Playing sounds to people while they sleep could be used to help them forget specific memories, a new study has revealed.

The early-stage discovery, by researchers at the University of York, could potentially be developed into techniques for attenuating traumatic and intrusive memories, the study authors say.

Previous research has found that playing ‘sound cues’ during sleep can be used to stimulate specific memories, but this latest study provides the first strong evidence that the technique could also be used to help people forget.

The study’s lead author, Dr. Bardur Joensen, a former PhD student in the Department of Psychology at the University of York, said: “While still highly experimental at this stage, the results of our study raise the possibility that we can both increase and decrease the ability to recall memories by playing sound signals when a person sleeps.

“People who have experienced trauma can have a wide range of distressing symptoms because of their memories of those events. While we are still a long way off, our discovery could potentially pave the way for new techniques for attenuating those memories that coexist with existing ones.” therapies can be used.”

For the study, 29 participants learned associations between overlapping word pairs. For example, they had to learn the word pairs ‘hammer – office’ and ‘hammer – Cardi B’.

The participants then slept overnight in the York University sleep lab. The research team analyzed their brain waves and when they reached deep or slow sleep (also known as stage-three sleep) they were silently played the word denoting the object (ie hammer).

Previous research has found that playing ‘sound cues’ during sleep can be used to stimulate specific memories, but this latest study provides the first strong evidence that the technique could also be used to help people forget. Image is in the public domain

Previous research had shown that learning a few words and playing a sound associated with that pair during sleep improved participants’ memory for the word pair when they woke up in the morning.

This time, when the word pairs overlapped, they found an increase in memory for one pair, but a decrease in memory for the other pair. This suggests that it is possible to selectively induce forgetting by playing associated sounds during sleep.

According to the researchers, sleep played a critical role in the effects they saw in their study.

Senior author of the study, Dr. Aidan Horner, of the Department of Psychology at York University, said: “The relationship between sleep and memory is fascinating. We know that sleep is critical to memory processing, and our memories tend to be better after a period of sleep. The exact mechanisms that being in play remain unclear, but during sleep it seems that important connections are strengthened and unimportant ones are thrown away.

“This research raises the possibility that this process can be manipulated so that sleep can be used to weaken painful memories.

“The next steps for our research team are to determine how these signals trigger forgetting so that we can turn the effect on and off and whether we can use the same technique to attenuate existing real-world memories.”

About this sleep and memory research news

Author: Shelley Hughes
Source: York University
Contact: Shelley Hughes – University of York
Image: The image is in the public domain

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Original research: Open access.
“Targeted memory reactivation during sleep may cause overlapping memories to be forgotten” by Bardur Joensen et al. Learning and memory


Abstract

Targeted memory reactivation during sleep can cause overlapping memories to be forgotten

Memory reactivation during sleep can form new memories into a long-term form. Reactivation of memories can be induced by giving auditory cues during sleep. While this approach to targeted memory reactivation (TMR) can amplify newly acquired memories, research has tended to focus on single associative memories.

It is less clear how TMR affects the retention of overlapping associative memories. This is critical, as repetitive retrieval of overlapping associations during awakening can lead to forgetting; a phenomenon known as retrieval-induced forgetting (RIF).

We asked whether a similar pattern of forgetting occurs when TMR is used to fuel reactivation of overlapping pairwise associations during sleep. Participants learned overlapping pairs; learned individually, alternating with other unrelated pairs.

During sleep, we cued a subset of overlapping pairs using TMR. While TMR increased retention for the first coded pairs, memory decreased for the second coded pairs. This pattern of retention was only present in couples who were not tested before going to sleep.

The results suggest that TMR can lead to forgetting; an effect similar to RIF during awakening. However, this effect did not extend to memories enhanced by pre-sleep retrieval. We therefore provide evidence for a reactivation-induced forgetting effect during sleep.

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