researchers measured serum levels of Tsimane people in Bolivia . A time spent hunting for food caused a spike in serum level . The larger the spike , the more oxytocin a ##roma produced on arrival home . increase in oxytocin was greater for those men who were absent longer .
Researchers tracked hormone levels of Tsimane people in Bolivia . A day spent hunting for food caused a spike in testosterone level . The larger the spike , the more oxytocin a man produced on arrival home . Increase in oxytocin was greater for those men who were absent longer .