Emotion processing and autism spectrum disorder: A review of the relative contributions of alexithymia and verbal IQ

•This systematic review investigates whether verbal ability and alexithymia contribute to emotion processing difficulties associated with ASD.•Verbal IQ has a strong influence on behavioural processing of emotions.•Alexithymia appears to have an influence on physiological and brain responses related to emotion processing.•As such, both verbal IQ and alexithymia should be considered to explain findings of studies of emotion processing and ASD.