According to a recent study, because of the way older brains process information, positive emotions are more often linked to the formation of memories.
A team of researchers at the University of Auckland in New Zealand, led by Dr. Donna Rose Addis in partnership with Dr. Elizabeth A. Kensinger of Boston College, studied memory in younger (ages 19-31) and older (ages 61-80) people. The scientists asked these two groups to examine two groups of photographs with either positive or negative themes, for instance, a wounded soldier versus a victorious athlete. While they looked at the pictures the subjects’ brains were monitored with a functional magnetic resonance imaging scan, (fMRI), which recorded the metabolic activity in different regions of their brains. They were also asked to remember as many photos as possible.
The results showed that there was no difference between the groups as far as the connectivity among regions used to form memories of negative content was concerned. Researchers did take note of significant differences when it came to forming memories of the positive content. Older adults showed two regions are linked to the processing of emotional content. These regions were strongly connected to the regions of the brain that are associated with memory formation: namely the amygdala, a region found between the ears; and the ventromedial prefrontal cortex, the area right behind the bridge of the nose. Young adults did not show this strong connection between emotion-processing regions and memory creation areas.
A conclusion that can be made based on these findings is that older people remember happy events quite well, since the brain regions that control the processing of emotions work together with the regions that control the processing of memories whenever those older adults experience positive events.
Younger people do not have these same kind of strong connections, therefore it would stand to reason that it is harder for them to remember the positive events in their lives over the long term.