Why Good Memories Last Longer!

Why do we remember some things well, while other memories fade? Researchers suggest it could be that good memories persist longer than bad - helping to keep the human race happy and resilient.

It was 80 years ago that the idea of negative memories fading faster was first proposed. Back in the 1930s psychologists collected recollections about life events like people's holidays - marking them as pleasant or unpleasant.

Weeks later an unannounced request came from the researchers to recall their memories. Of the unpleasant experiences nearly 60% were forgotten - but only 42% of the pleasant memories had faded. This is something which many of us recognise - after a holiday we might reminisce about the pleasant days out and people we met - but forget about how terrible the flight delays were.

Later studies of this so-called Fading Affect Bias or FAB were more rigorous. In the 1970s instead of asking people to recall random memories - where people might be biased towards recalling just positive ones - the participants were asked to keep diaries, recording the emotional intensity of their memories.

However, because around 80% of all psychological research is carried out on American students, it wasn't clear whether the bias would exist in other cultures too. To see if it was universal, Timothy Ritchie from the University of Limerick in Ireland decided to analyse data from samples collected by academics at six universities around the world. These researchers had access to participants from many different English-speaking ethnic groups including African-Americans, Ghanaians, Germans, Native Americans and New Zealanders of both European descent and Maori/Pasifica descent.

In all, 2,400 autobiographical memories were included, from 562 individuals in 10 countries. The researchers found that the FAB occurred in each study, regardless of the cultural background of the participants. The authors believe this shows that the faster fading of unpleasant memories is a pan-cultural phenomenon and this helps individuals to process negativity and adapt to changes in their environment whilst retaining a positive outlook on life.

Further evidence in support of this hypothesis is that one group of people which has real problems recalling positive memories is those with severe depression. Dr Tim Dalgleish, a clinical psychologist from the University of Cambridge, tries to help those with serious depression to access positive memories. The technique he has used is known as the method of loci. This method is thousands of years old and uses visual imagery which you imagine along a route or in a location such as your home.

Subjects are asked to identify a series of happy memories and then "place" them along a route such as a journey to work or college - or even inside their own home. Dr Dalgleish says this is a vital part of the process "You set up say 10 points on the route - so the front door, the porch, the kitchen and lounge if it's around your house - and then you choose the memories you'd want to put in your suitcase - the sort of things you'd like to bring to mind when times are tough. The researchers found that the method seems to have lasting benefits, with effects still seen when people were re-tested a week later. Emma Brinkley, one of the test subjects, has been surprised how long-lasting those memories are. "I find myself on certain days feeling a bit low and so I simply have just put myself through that familiar route and just try to think of some happy memories to try and cheer myself up. Some days it is more effort than others b I have found that there has been a real profound lifting of my mood."

By Paula McGrath, 3 May 2014

http://www.bbc.com/news/health-27193607