A huge variety of factors are related to memory, from mood to personality to what substances have been consumed. One recent study, for example, found that older adults with higher openness to experience also experienced fewer cognitive complaints each day; other work has found a relationship between self-reported memory and traits including neuroticism and extraversion.
Now, in a study published in Psychological Science, Emily F. Hittner from Northwestern University and team have looked at the relationship between memory and positive affect — the experience of pleasant emotional states like enthusiasm, pride or joy. And they found less memory decline over time in those participants with higher levels of positive affect.
The team analysed data from 991 participants who had taken part in a longitudinal study of households in the United States. At the first time point, when participants were an average of 55 years old, they had reported their levels of positive affect using two scales, which asked how often during the last month they had felt enthusiastic, active, peaceful, satisfied and so on. They also completed measures of depression and negative affect, as well as personality trait scales.
Participants also took part in a memory assessment. In this test, they were read a list of 15 unrelated words and then had to recall as many as they could immediately (immediate recall) and, in a test they were not warned about, after fifteen minutes (delayed recall). Then, nine years later, participants completed this memory test again.
The team found that, overall, people who reported more positive affect at the first time point showed less memory decline over these nine years. Particular facets of positive affect were also associated with less memory decline — greater enthusiasm, cheerfulness, pride, and feelings of calm and peace were all related to slower memory decline, while greater attentiveness or satisfaction were not. Importantly, all the analyses took into account other factors like participants’ negative affect, personality traits and age, suggesting that these weren’t responsible for the results.
Why positive affect is related to a slower rate of memory decline, however, was less clear. The team suggests a number of pathways that could link the two: if you have a positive outlook on life, for example, you might be more inclined to engage in adaptive health behaviours or to foster beneficial social relationships. Positive affect in and of itself may not be the crucial factor, in other words, instead acting as the source of behaviours that improve or protect health.
Memory loss can be devastating, particularly in older adults — forgetting to take vital medication, for example, has serious consequences, and the emotional and social ramifications of forgetting the names or faces of acquaintances can also be severe. Memory decline can also predict the onset of dementia. Developing ways to predict (and prevent) memory loss is an important task. Screening for positive affect as a way of predicting potential memory decline, as the team suggests, could therefore have implications for cognitive as well as mental health, helping improve wellbeing across the board.