In utero testosterone exposure influences physiological responses to dyadic interactions in neurotypical adults

OBJECTIVE: We investigated how different levels of prenatal exposure to testosterone influence physiological reactions to dyadic interactions, hypothesising that higher levels of prenatal testosterone are linked to greater physiological responses. METHOD: Autonomic nervous system responses to dyadic interactions focussed on social or physical norms were measured. Physiological assessment of excitability (heart rate, facial temperature) and a behavioural assessment (Likert items judgements) were run on 25 neurotypical participants who had distinct testosterone exposure levels in utero. In utero exposure to testosterone was assessed measuring 2D : 4D (ratio between the lengths of the index and the ring fingers). RESULTS: Higher testosterone exposure participants showed greater physiological arousal: a greater heart rate decrease, independent from scenario type (p<0.05), and opposite facial temperature changes in response to social (increase) (vs.) physical scenarios (decrease) were found (Left-cheek: p<0.05; Right-cheek: p<0.05). CONCLUSION: These findings suggest a long-term influence of prenatal environment on adults' physiological responses during social situations.