Summary: Repeated experiences in the same environment can leave a deeper impression on our brain.
Source: University of Amsterdam
It is common to find that memories are more vivid when shared with friends than they are with others. Other times, memories can be mixed up. But why do our memories change? According to Vanessa van Ast (clinical psychologist), it is all about the spatial context.
Repeated experiences in the same environment are more deeply etched in our memories. However, when an experience occurs in a new environment, it pushes previous memories to the background.
Our episodicmemoryenables us to recount things that we personally experienced. People can recall funny details about the film they saw together, such as when they reminisce about it with a friend. People may feel their heart race again when they think back to a film that touched them emotionally. This is because emotional memories trigger our physical memory and make us relive those experiences more often.
However, memories can be altered. Sometimes we forget details. Or our memories can be triggered repeatedly to trigger the emotion.
Vanessa van Ast, clinical psychologist, studies episodic and emotional memories under different conditions. Van Ast, who was awarded a Veni grant from the Dutch Research Council (NWO), explains that one of the key findings of her research is that the environment in which people recall an experience has a big impact on how they remember it: ‘We already knew that spatial context affects memory recollection, but we did not have a good understanding of what happens to memories afterwards.’
Researching memory in the laboratory
First, how can you research the workings and functioning of human memory? ‘A personal memory can be influenced by a million things,’ says Van Ast.
‘It is impossible to identify all those factors as a researcher, so we will never be able to determine exactly what happened during an experience.’
Van As did experimental research in a psychology lab to address this problem. She isolated core components of her experiences in order to manipulate them and see how they are remembered.
She used materials that were made up of different elements such as sound, background images, and foreground images. Participants were shown various elements at different times and asked to recall a specific memory. This revealed the brain’s associations and the reasons why a memory changes.
‘Because the way memory works is very associative,’ Van Ast explains. ‘At times, we also used distressing images, such as a picture of a broken leg accompanied by cracking noises, to simulate emotional experiences and measure physical responses, such as an elevated heart rate.’
Environment is key to what you can remember
Van Ast was particularly interested in the impact of environment on how our memory works: ‘We already knew that the environment is the strongest trigger for the recollection of a memory. The environment is a memory trigger because every experience takes place within a particular environment. But we did not have a good understanding of what happens to memories afterwards.’
To find out, she did an experiment where participants saw a number of words in a particular context and had to come up with a story based on those words (the original ‘experience’). The next day, the participants were exposed to similar ‘experiences’, but the original words were successively linked to new words.
‘Crucially, we sometimes presented new words in the same context as before and sometimes presented them in a new context.’
The participants were tested on their memory to see if they could recall the linked words.
‘We found that context was critical,’ says Van Ast. ‘When two experiences took place in the same context, both memories, as well as the associations between them, were imprinted much more deeply. However, if they were in different contexts, the second one was more easily remembered than the first. And the associations between them were also more poorly remembered.’
How would this work in real-life? Van Ast cites the example of going to the cinema together with a friend. ‘Some time later, you watch another film with that friend in the same cinema. You and your friend will share your memories of your cinema visits the next day. You’ll discover that both your first visit and second to the cinema were reaffirmed in your memories. You will be able to recall which film you saw, and what drinks and snacks were consumed. But if you had watched the second film with the same friend in a different cinema, the original memory would have faded enormously, whereas you would have had a strong recollection of the new experience.’
Different contexts do not reinforce memories
Van Ast concluded that when the spatial context changes our memory is triggered by this change to switch to the new context. ‘Our brain apparently prioritizes the new context over the original memory. This finding goes against many theories that hold that different contexts actually make memories more unique and stronger and therefore lead to less interference between memories.’
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Focus on emotional memories
Van Ast wants to dig deeper into our emotional memories. She discovered that when an emotional or negative experience follows, it reinforces the memory of the first experience. ‘In this experiment, the emphasis was on recounting episodic details. But it’s still unclear what factors can cause emotional responses to change.’
That is why Van Ast now wants to research how emotional responses to past experiences can change and how context can be used to influence emotional memories: ‘To reinforce positive effects of therapy, for instance. This is still uncharted territory, but we do know that context can play a big role when you want to change memories.’
This memory research news
Author: Press Office
Source: University of Amsterdam
Contact: Press Office – University of Amsterdam
Image: The image is in public domain
Original Research: Closed access
“The contextual similarity between events determines whether episodic memory enhancement is better than impairment.” by Vanessa van Ast et al. PNAS
Abstract
The contextual similarity between events determines whether episodic memory enhancement is better than impairment.
Over a century, memory interference has been attributed to the stability of spatial context across related episodes. This can lead to memory retrieval being impaired. Contemporary memory integration theory predicts the opposite.
This experiment aimed to correct this discrepancy by manipulating the local context similarity between temporally dissimilar but related episodes, and testing the direction of memory change.
A series of experiments have shown that contextual stability results in memory integration and marked reciprocal strength. Contrariwise, variations in context can lead to competition that results in new memories being enhanced at the expense or original memories. These patterns were almost reversed in another experiment, where context was restored during recall.
These observations 1) identify the importance of contextual similarity between original and new memories in the volatility and memory. 2) challenge the classic and modern theories of episodic memory change. 3) show that the sensitivity context-induced memory modifications to retrieval conditions may be compatible with paradoxical predictions of integration and interference theory.
