Emotional outbursts during argument trigger defensive flight-or-fight responses

Evidence

An outburst of emotion can help show the other person how you feel, how important or frightening a topic is to you, how great your concern. As a rule, however, such conversations are unproductive, can easily derail and have the opposite effect. The other person may be put on the defensive, statements are made in the heat of the moment that you later regret, and rifts are deepened. There is a danger that if you are highly agitated, you will not be able to listen at all and will resort only to primitive flight/fight responses. — Holm Gero Hümmler, Ulrike Schiesser, Fact and Prejudice, 377