A systematic review and meta-analysis of empathy in autism: The influence of measures

Empathy deficits are considered a core attribute of autism and are scored in standardized autism diagnostic instruments. However, empirical evidence concerning empathy in autism is contradictory. This systematic review, which included 226 studies, thus offers a comprehensive overview of empathy in autism. It additionally examined the impact of the chosen empathy measure and the effect of several moderators. The results reveal a large effect size for cognitive empathy (g = -0.85) and unidimensional empathy (g = -1.70), but only a small effect size for affective empathy (g = -0.17), which became non-significant when limiting analyses to high-quality studies. Meta-regressions suggest that publication year, study quality, alexithymia, verbal IQ, and age do not moderate empathy, whereas sex specifically moderates unidimensional empathy. Critically, there were notable differences in effect sizes obtained across empathy measures and even between subscales of the same measure. For instance, results for the affective empathy subscales of the Interpersonal Reactivity Index reveal lower empathic concern (g = -0.59) but increased personal distress (g = 0.67) in autistic relative to typical participants. A qualitative review of ecological and neuroimaging tasks mostly demonstrated minimal autistic versus non-autistic differences. This meta-analysis thus suggests that measuring empathy as a unidimensional construct may both distort and increase the notion of an empathy deficit in autism.