Type A individuals process stimuli with the temporal lobe. They are visual, practical, spontaneous, they process information instantaneously, and they consequently act and react swiftly – at lightning speed. The neurotransmitter serotonin plays the most significant role in Type A individuals: when it is at low levels, it makes them fast and effective, whereas, when it reaches high levels, it causes panic reactions, irritability and extreme hastiness leading to negative results. Haste and tension give them agility enabling them to easily overcome obstacles and make them practical, confident, and perceptive. Their inner tension makes them spontaneous and forces them to act and take risks. It makes them impatient and quick-tempered.

Type B individuals process stimuli with the amygdala. They are auditory, analytical, careful, patient, with high self-control and a strong sense of responsibility toward fulfilling their goals, they process information successively, which is why they are cautious in action. For Type B individuals, the neurotransmitter dopamine plays the most important role: when it is at low levels, it allows the person to take action, but, when it reaches high levels, it leads to repetitive thinking, which hinders action. Type B individuals tend to suffer from anxiety; they worry about the future and procrastinate. Their tendency to worry and their fear(s) make them particularly careful. They seldom take a wrong decision, since they seldom take risks.