People possessing this class of Thumb belong to the Elementary type as far as Will is concerned.

They are brutal and like animals in their unreasonable obstinacy.

If they are opposed they fly into ungovernable passions and blind rages.

They have no control over themselves, and are liable to go to any extreme of violence or crime during one of their tempers.

In fact the clubbed-shaped Thumb has also been designated "the murderer's thumb" on account of so many murderers having been found with this formation.
The possessor of a Clubbed Thumb could not, however, plan out or premeditate a crime, for he would not have the determined Will or power of reason to think it out.
The shorter the Thumb, the nearer the possessor is to the brute in passion and lack of self-control.
The "waist-like" Thumb (Fig.