We examine evidence for whether brain volume reductions and neurotransmitter decline can account for older adults’ emotion recognition difficulties relative to young adults. We also consider whether emotion recognition decline is related to general cognitive decline or the positivity bias. Despite recent claims, older adults’ emotion recognition difficulties are not consistent with the positivity bias. Links to general cognitive decline are not strong, although future research could shed further light on this issue by examining links to speed of processing. We conclude that there is some evidence for the idea that neurotransmitter decline might relate to older men’s emotion recognition declines (though not older women’s), but with only two studies, more research is needed. There are more studies examining brain volume reductions, with links between emotion recognition and decline in the frontal and temporal lobes clearest.