It is easier to teach a child, because its mind is like a blank canvas.Chen Yingjun

When grown ups start learning Taijiquan (Tai Chi), they already have a collection of preconceived ides about what this art is about, and maybe even about some of its technical aspects. This is all the more true, if they have read about it before, or practiced another martial arts style.
Almost any idea brought to class tends to make learning more difficult (one exception might be experience in meditation). Taijiquan (Tai Chi) is a very un-obvious art, with innumerable depth levels, and a very unique approach to body mechanics.

When children start learning, even if they have some previous experience, they are naturally more open to learning. If a child is four or five years old, it will learn with a completely pure heart, and its mind will be free to take in information. This is the attitude we should adopt when learning Taijiquan (Tai Chi): complete non-attachment to what we think we already know.

There’s a very concrete reason for this. Say you are learning the posture “Hand hides arm and fist”. The first reaction most people have is, “oh, that’s a punch”. If that thought sticks, you will miss not only the other applications of this move, but your body will try to throw a punch in the way you already know. If, on the other hand, you had never seen a punch before, and had no idea what a punch is, you’d do your best to simply copy the way the teacher moves – which is precisely what you should do anyway.