The word, in caricatures, means the habits an artist has when making decisions in his drawing. When attempting to get a likeness, tendencies are a hindrance in every respect.
A beginning artist might have the tendency of giving everyone the exact same nose shape. A third year artist may routinely space the eyes far apart, or close together. Perhaps a veteran will have more subtle habits. It might be that he gravitates toward rounded off shapes or parallel lines or some other kind of formal preference.
Now, you might ask, could it be that you are calling "tendency" what is, in fact, a deliberate style? My answer is that, deliberate