What are the effects and consequences of what Van Helsing describes as Dracula's" child brain"?

Van Helsing and Mina both use the terms of physiognomy in this chapter, referring again and again to the Count's "child brain." He is a criminal "type" (Mina even refers to two renowned physiognomists to back up her classification of the Count), and thus he has predictable limitations. He is selfish (he thinks of escape at all costs), and he uses the same strategy whether he is a mortal invading/escaping Turkey or an undead invading/escaping England.