Well, it starts when they take a baby elephant, and tie a rope around its hind leg, and attach it to a stake in the ground. The baby fights and fights, trying to pull the rope free, but it does not have the strength to do so. It continues to try, sometimes for days, expending all its energy, until one day, it stops trying – It has finally learnt that it is unable to pull free.
Attempts of a young one.
You know, as that elephant grows up, the circus handler simply makes the loop on it’s leg wider using the same rope even until it is an adult. And you know what? That elephant never tries again to break free. it has learnt the “truth” that it is unable to do so. It may as well be a thick chain, because the elephant has learnt that it is futile to even attempt to pull it out the ground.