The hands and arms move with intention and exacting, angular precision as they project outward. The fingers will either become pinched, or pointed in rhythm with verbal emphasis they wish to convey.
This signal reveals a psychology that is actively reducing variables down; consolidating the situation into one or two main axioms of reason which explain the topic at hand. The pointing emphasis is a metaphor for this singularity of perspective being experienced. This person is one which likes to have exact definitions for the concepts which construct their view of reality.