Changes in emotion recognition are observed in ageing, in dementia, after brain lesions and as a function of mental health factors, such as depression. Older adults have been argued to show a ‘positivity bias’, which has been associated with a relatively spared recognition accuracy for positive emotion, and an increased tendency to label emotions as positive. This bias has been suggested to support mental well-being in ageing. However, it has also been found in association with cognitive decline and brain lesions. Here, we investigated the brain correlates of this age-related positivity bias. We used multimodal brain imaging in a large of human adults (n=665, 333 females) drawn from a population-derived cohort across the adult lifespan, together with a psychometric analysis of an emotion recognition task using facial expressions. Apart from overall reductions in expression recognition accuracy, older adults showed a notable pattern of increased perceptual thresholds for negative emotions and a reduced threshold for the positive emotion, even after accounting for general face recognition abilities. This positivity bias in labelling emotions was strongly associated with lower cognitive performance in older people, but not with (non-clinical) depressive symptoms. It was also associated with reduced grey matter volume in bilateral anterior hippocampus-amygdala, and increased functional connectivity between these regions and orbitofrontal cortex. Together, this age-related positivity bias is associated with cognitive decline and structural and functional brain differences. A positivity bias in emotion recognition may therefore reflect an early marker of neurodegeneration; a hypothesis that could be tested in future longitudinal studies. Significance statement Emotion recognition changes with age, with older adults showing a "positivity bias"—reduced recognition of negative emotions, and bias in labelling emotions as positive. While this has been theorized as an adaptive mechanism supporting emotional well-being, emerging evidence suggests it may instead signal cognitive decline or neurodegeneration. Using a large population-based cohort (n=665), multimodal brain imaging, and a psychophysical emotion recognition task, we found that increased age-related positivity bias was strongly linked to cognitive decline but not depressive symptoms. Moreover, this bias was associated with differences in the structure and functional connectivity of anterior hippocampus-amygdala. These findings suggest that positivity bias may be an early marker of neurodegeneration, with implications for early detection and intervention in age-related cognitive decline.
Wolpe et al. (Mon,) studied this question.