“There Are Age-Related Changes in Neural Connectivity during the Encoding of Positive, but Not Negative, Information,” Cortex, May 2009
An international team of psychologists put a group of people aged 19 through 31 and a group aged 61 through 80 into a functional MRI and showed participants positive, neutral and negative photographs. It turned out that the brains of younger and older people responded similarly when they saw gunshot wounds, but for the older people, their ventromedial prefrontal cortex and amygdala, which are involved in emotion, and the hippocampus, which governs memory, all responded when they saw positive images like kittens, indicating the formation of a stronger memory. (The younger brains showed no such effect.) The researchers think this may explain the “positivity effect,” the idea that as people age, positive memories tend to get stronger while bad memories fade more quickly.
We’re not sure exactly why older folks look on the bright side, but before this study we weren’t even sure if there was a biological basis for the phenomenon. The next step is to establish whether the positivity effect is simply a part of aging or whether, as older adults feel time slipping away, they are more likely to emphasize the positive. This could help determine if there are differences in the memory encoding between elderly people with depression and those with a cheerier disposition.