By Emma Young

Most people find it easy to infer the emotional state underlying a scowl or beaming smile. But not all facial emotional signals are so obvious. Sensitivity to these less obvious emotional signals varies from one person to another and is a useful skill, improving relations with other people and benefiting psychological wellbeing. As well as varying between individuals, are there also shifts in this ability during a typical person’s life? And, if so, might these age-related changes be relevant to known high-risk periods for psychological problems and the onset of mental illness? A new study, published in the Journal of Experimental Psychology, provides some answers.

Lauren Rutter at Harvard Medical School and her colleagues analysed data on 9,190 people aged 10 to 85 from the US, the UK, Canada, India, Australia and Germany. These participants completed the Emotion Sensitivity test on the testmybrain.org website. They were shown 56 pairs of faces, and each time, they were asked which of the pair was “more angry”, “more happy”, or “more fearful”. The faces had been carefully manipulated so that the difficulty level in making these judgements was “easy”, “medium” or “hard”.

The researchers found that sensitivity to facial cues of anger increased steeply from age 10 to age 14, then increased at a slower rate until age 30, followed by a gradual decrease in sensitivity into late age. From an evolutionary perspective, the sharp rise in anger sensitivity through early to mid adolescence makes sense: “As adolescents are learning to navigate their social worlds, knowing if their actions are inciting anger in others is a particularly adaptive skill,” the team notes. Other work on adolescents in the UK found that while bullies didn’t differ from others in their emotion recognition skills, victims of bullying were less able to recognise anger and fear in particular. “Thus, learning to discriminate anger and change actions accordingly may serve an important social function,” the researchers write.

Fear sensitivity showed a marked increase at around age 19, with a peak at about 34 years. It then remained relatively high until around 45–50, then reduced. Being able to spot fear in others is clearly useful for avoiding dangerous situations, and for protecting children from danger – but hyper-sensitivity to other people’s fear could play a role in the development of anxiety disorders. Agoraphobia, OCD, PTSD, panic disorder and generalised anxiety disorder tend to develop between the ages of around 21 and 35, which is when the data indicated that sensitivity to fearful expressions rises, the team noted.

Meanwhile, happiness sensitivity showed a different lifespan pattern: after increasing between the ages of 10 and 22, there was “a very mild decline or plateau”, with sensitivity remaining relatively undimmed even into older age. The preservation of happiness sensitivity – combined with less awareness of other people’s anger and fear – may help to explain the results of studies finding that older adults (at least those with adequate social relationships) tend to report feeling happier more of the time than younger people.

The researchers also noted some possible gender differences: the data suggested that men’s anger sensitivity may continue to increase relatively steeply for a few more years, compared with women’s, and that their fear sensitivity improves more rapidly during adolescence, for example. However, these age-gender differences were not statistically significant.

There are some limitations of the study: most notably the participants were self-selecting and so may not be representative of the general population. But the large sample size is an advantage. Overall, the data certainly suggests that sensitivities to different emotions don’t develop in the same way across the lifespan, and that this may be relevant to age-related changes in psychological wellbeing.

—Emotion sensitivity across the lifespan: Mapping clinical risk periods to sensitivity to facial emotion intensity

Emma Young (@EmmaELYoung) is Staff Writer at BPS Research Digest