Positivity effect in aging: Evidence for the primacy of positive responses to emotional ambiguity

Abstract

Older compared to younger adults show greater amygdala activity to positive emotions, and are more likely to interpret emotionally ambiguous stimuli (e.g., surprised faces) as positive. While some evidence suggests this positivity effect results from a relatively slow, top-down mechanism, others suggest it emerges from early, bottom-up processing. The amygdala is a key node in rapid, bottom-up processing and patterns of amygdala activity over time (e.g., habituation) can shed light on the mechanisms underlying the positivity effect. Younger and older adults passively viewed neutral and surprised faces in an MRI. Only in older adults, we found that amygdala habituation was associated with the tendency to interpret surprised faces as positive or negative (valence bias), where a more positive bias was associated with greater habituation. Interestingly, although a positive bias in younger adults was associated with slower reaction times, consistent with an initial negativity hypothesis in younger adults, older adults showed faster ratings of positivity. Together, we propose that there may be a switch to a primacy of positivity in aging.

Social connectedness and negative affect uniquely explain individual differences in response to emotional ambiguity

“…In other words, when the default response is negative, the impact of negative affect (temperament and symptomology) may be diminished. In contrast, in older adults, a positive valence bias is more likely 43,62 and may even represent the new default 63 . Thus, in this population, increases in negative affect appear to play a more crucial role in impacting valence bias.…”

“…Third, it engages an amygdala-prefrontal cortex (PFC) circuitry 21 , 47 , 61 , similar to that implicated in disorders characterized by a negativity bias and emotion dysregulation 66 , 68 . Fourth, this task is developmentally appropriate—it has been leveraged for studying valence bias and its association with depressive symptomology and emotion regulation across the lifespan (ages 6–88 years), from children—including those experiencing early life stress 59 – 61 to older adults 43 , 62 , 63 . Finally, it is sensitive to a range of contextual manipulations, including but not limited to stress 69 and exercise 70 .…”