Sound cues during sleep can help people forget specific memories

Summary: Previous studies have shown that sound cues played during sleep can improve a person’s memory. A new study reports that sound cues during sleep may help weaken intrusive and traumatic memories. Researchers say that sound cues during sleep can be used to increase or decrease the ability to recall specific memories.

Source: University of York

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

A preliminary discovery by York University researchers could potentially be developed as a technique to help weaken traumatic and intrusive memories, the study authors said.

Previous research has shown that playing ‘sound signals’ during sleep can be used to boost certain memory, but this latest study provides the first strong evidence that the technique can also be used to help people forget.

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

“People who have experienced trauma can suffer a wide range of distressing symptoms due to memories of those events. Although still a long way off, our discovery could potentially pave the way for new strategies to weaken those memories that could be used alongside existing therapies.”

For the study, 29 participants learned the relationship between overlapping pairs of words. For example, they were asked to learn the word pairs ‘Hammer – Office’ and ‘Hammer – Cardi B’.

Participants then slept overnight at the University of York’s sleep lab. The research team analyzed their brain waves and when they reached deep or slow-wave sleep (also known as stage-three sleep) they silently played the sound that meant the object (i.e. the hammer).

Previous research has shown that learning a pair of words and playing a sound associated with that pair during sleep improves participants’ memory of the pair when they wake up in the morning.

This time, when pairs of words were overlapped, they increased memory for one pair, but decreased memory for the other pair. This suggests that selective forgetting is possible by playing associated sounds during sleep.

According to the researchers, sleep played an important role in the effects they saw in their study.

The study’s senior author, Dr Aidan Horner, from the Department of Psychology at the University of York, said: “The relationship between sleep and memory is fascinating. We know that sleep is important for memory processing, and our memories are generally better after a period of sleep. The exact mechanisms at play remain unclear, but during sleep It seems that important connections are strengthened and unimportant ones are discarded.

“This study raises the possibility that this process can be manipulated to help sleep weaken painful memories.

“The next steps for our research team are to establish how these cues cause forgetting, so that we can turn the effect on and off, and whether we can use the same strategy to weaken existing real-world memories.”

The news of this research on sleep and memory

Author: Shelly Hughes
Source: University of York
Contact: Shelley Hughes – University of York
Image: Image is in public domain

Original Research: Access to all.
““Targeted memory reactivation during sleep may cause overlapping memories to be forgotten.” By Bardur Joensen et al. Learning and memory

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abstract

Targeted memory reactivation during sleep can induce forgetting of overlapping memories

Memory reactivation during sleep can shape new memories into long-term forms. Memory reactivation can be induced by providing auditory cues during sleep. Although this targeted memory reactivation (TMR) approach can strengthen newly acquired memories, studies have tended to focus on single associative memories.

It is less clear how TMR affects retention for overlapping associative memories. This is critical, because repeated retrieval of overlapping associations during wakefulness 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 elicit reactivation of overlapping pair-wise associations during sleep. Participants learned overlapping pairs; Learned separately, interleaved with other unrelated pairs.

During sleep, we generated a subset of overlapping pairs using TMR. While TMR increased retention for the first encoded pair, it decreased memory for the second encoded pair. This pattern of retention was only present for pairs that were not tested before sleep.

The results suggest that TMR can be forgotten; A RIF-like effect during wakefulness. However, this effect did not extend to memory which was strengthened by retrieval prior to sleep. We therefore provide evidence for a reactivation-induced forgetting effect during sleep.