With age, we become better able to understand the meaning behind others’ nonverbal cues. In other words, we become more skilled at identifying others’ emotional states or attitudes based on their facial expressions, postures or gestures, or tone of voice. Previous research has found that the ability to recognize emotions in vocal cues (i.e., the way in which someone says something, beyond their verbal content) follows a more protracted developmental trajectory throughout adolescence than the same ability with facial expressions. Are there similar differences in the maturational trajectory of the neural representation of both types of nonverbal cues?
The current study examined age-related changes in a) facial and vocal emotion recognition skills, and b) in neural activation to both types of stimuli in adolescence. A group of 8- to 19-year-old participants were asked to complete both a facial and a vocal emotion recognition task—in which they were asked to identify the intended emotion in other teenagers’ facial expressions and voices—while undergoing functional magnetic resonance imaging (fMRI). We found that accuracy on the emotion recognition tasks began to plateau around age 14 for faces, but continued to increase linearly throughout adolescence for voices. At a neural level, a variety of subcortical regions, visual-motor association areas, prefrontal regions, and the right superior temporal gyrus responded to both faces and voices. While there were no age-related changes in activation within these areas when responding to faces, prefrontal regions (specifically, the inferior frontal cortex and dorsomedial prefrontal cortex) were more engaged when hearing voices in older adolescents. These findings suggest that the maturation of vocal emotion recognition skills and associated neural responses in frontal regions of the brain are continuing to develop throughout adolescence, following a more protracted trajectory than other social cognitive skills like the ability to interpret facial emotions. This may make it harder for teenagers to navigate social situations in which they must rely on vocal cues—for instance, when others are wearing masks.
