Many of us enjoy writing in a diary, reading autobiographies or nostalgically reflecting with others about past times.

Why is remembering our past so important? Are there downsides? And what can we do if dwelling on the past bothers us?

Read more: Explainer: what is memory?

Memories make us human

Over several decades, researchers have shown remembering your past is fundamental to being human, and has four important roles.

1. Memories help form our identity

Our personal memories give us a sense of continuity — the same person (or sense of self) moving through time. They provide important details of who we are and who we would like to be.

Read more: Why we remember our youth as one big hedonistic party

2. Memories help us solve problems

Memories offer us potential solutions to current problems and help guide and direct us when solving them.

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3. Memories make us social

Personal memories are essential for social interactions. Being able to recall personal memories provides important material when making new friends, forming relationships and maintaining ones we already have.

Read more: The power of 'our song', the musical glue that binds friends and lovers across the ages

4. Memories help us regulate our emotions

Our memories provide examples of similar situations we’ve been in before. This allows us to reflect on how we managed that emotion before and what we can learn from that experience.

Such memories can also help us manage strong negative emotions. For example, when someone is feeling sad they can take time to dwell on a positive memory to improve their mood.

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Memories help us function in our wider society

Dwelling on our personal memories not only helps us as individuals. It also allows us to operate in our socio-cultural context; society and culture influence the way we remember our past.

For instance, in Western individualistic cultures people tend to recall memories that are long, specific, detailed and focus on the individual.

In contrast, in East Asian cultures people tend to recall more general memories focusing on social interactions and significant others. Researchers have seen these differences in children and adults.

Read more: 'Remember when we...?' Why sharing memories is soul food

Indeed, the way parents discuss past events with their children differs culturally.

Parents from Western cultures focus more on the child and the child’s thoughts and emotions than East Asian parents. So, there are even cultural differences in the ways we teach our children to dwell on the past.

People from Western individualistic cultures tend to recollect specific unique memories that reaffirm someone’s uniqueness, a value emphasised in Western cultures. In contrast, in East Asian cultures memories function to assist with relatedness and social connection, a value emphasised in East Asian cultures.

Memories and ill health

As dwelling on the past plays such a crucial role in how we function as humans, it is unsurprising that disruptions in how we remember arise in several psychological disorders.

People with depression, for instance, tend to remember more negative personal memories and fewer positive personal memories than those without depression. For example, someone with depression may remember failing an exam rather than remembering their academic successes.

People with depression also have great difficulty remembering something from a specific time and place, for instance “I really enjoyed going to Sam’s party last Thursday”. Instead they provide memories of general experiences, for instance, “I like going to parties”.

We have found people with depression also tend to structure their life story differently and report more negative life stories. They also tend to remember periods of their life, such as going to university, as either distinctly positive or negative (rather than a combination of both).

Disturbances in memory are also the hallmarks of post-traumatic stress disorder. This is when unwanted, distressing personal memories of the trauma spontaneously pop into the mind.

Read more: Explainer: what is post-traumatic stress disorder?

People with anxiety disorders also tend to have biases when remembering their personal past. For instance, all of us, unfortunately, experience social blunders from time to time, such as tripping getting onto a bus or spilling a drink at a party. However, people with social anxiety are more likely to be consumed with feelings of embarrassment and shame when remembering these experiences.

Read more: Explainer: what is social anxiety disorder?

Finally, an excessive, repetitive dwelling on your past, without generating solutions, can be unhelpful. It can result in emotional distress and in extreme instances, emotional disorders, such as depression, anxiety and post-traumatic stress disorder.

I don’t want to dwell on the past. What can I do?

If dwelling on the past bothers you, these practical tips can help.

Set aside a certain time of the day for your memories. You could write in a diary or write down your worries. Writing about important personal experiences in an emotional way for as little as 15 minutes a day can improve your mental and physical health.

Practice remembering specific positive memories from your past. This can allow you to engage differently with your memories and gain a new perspective on your memories.

Learn and practise mindfulness strategies. Instead of dwelling on painful memories, a focus on the present moment (such as attending to your breath, focusing on what you can currently see, smell or hear) can help break a negative cycle

When dwelling on past memories try being proactive and generate ideas to solve problems rather than just being passive.

See your GP or health practitioner if you’re distressed about dwelling on your past.

If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14.

Laura Jobson has previously received funding from NIHR.