Hardwired and evident early in life, “affective sharing” is strictly automatic mirroring of the ‘bottom up’ aspect of other’s emotions, for example, babies crying at the sight of another baby crying
a.k.a. emotional contagion
a.k.a. vicarious emotional arousal
source: Decety J., & Meyer, M. (2008). From emotion resonance to empathic understanding: A social developmental neuroscience account. Development and Psychopathology 20, 1053–1080. doi:10.1017/S0954579408000503