"Fight or flight" redirects here. For other uses, see Fight or flight (disambiguation). The fight-or-flight or the fight-flight-freeze-or-fawn[1] (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.[2] It was first described by Walter Bradford Cannon in 1915.[a][3] His theory states
![Fight-or-flight response - Wikipedia](https://cdn-ak-scissors.b.st-hatena.com/image/square/669cd20c8934ae8affaed989cc1f2e2bcb073894/height=288;version=1;width=512/https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F6%2F64%2FCat_and_dog_standoff_%25283926784260%2529.jpg)