The person will nod their head or jut it forward as an emphasis of articulation. These nods may be brief and jittery, or long and accentuated. In each case, there is a sharp, angular halt at the end of each head nod, denoting the finality of judgment.
This signal reveals a psychology that is presently relaying their convictions and beliefs to others; pushing their paradigm out toward the audience. Their psyche is, consciously or unconsciously, aiming to persuade, move and change the opinions (and ultimately actions) of their audience. The focus of their mind is presently concerned with the practical and logistical implications of the topic.