You can picture a guard that was never switched on by anyone and never has to be told. Something dangerous comes near, and the guard moves on its own: the body coughs, or the mind puts a memory out of reach. Both uses share that one shape — automatic, protective, and not chosen.
defence mechanism 可以想成「一個沒有人去開、也不用交代的守衛」。危險靠近的時候，它自己就動了：身體咳出來，或是心裡把一段記憶推到拿不到的地方。兩個意思共用這個樣子——自動發生、目的是保護、不是誰決定的。
登入就可以看每一支怎麼連回核心畫面。