I think it is mainly just a question of poor translation, sometimes words that sound almost the same have slightly different meaning in different languages. For the most part they seem to mean similarities in the body language, similar expressions, gestures, tone of voice, etc. that representatives of the same type sometimes exhibit and that can be of use in typing. Therefore for example visual identification is difficult if you can only look at a picture or two but apparently much more reliable if you can observe the person you are trying to type for some time.