The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom

by Jonathan Haidt

The sympathetic system prepares your body for “fight or flight” and the parasympathetic system calms you down. Both are active all the time, in different ratios. Your behavior is governed by opposing motivational systems: an approach system, which triggers positive emotions and makes you want to move toward certain things; and a withdrawal system, which triggers negative emotions and makes you want to pull back or avoid other things. Both systems are always active, monitoring the environment, and the two systems can produce opposing motives at the same time18 (as when you feel ambivalence), but their relative balance determines which way you move. (The “like-o-meter” is a metaphor for this balancing process and its subtle moment-by-moment fluctuations.) The balance can shift in an instant: You are drawn by curiosity to an accident scene, but then recoil in horror when you see the blood that you could not have been surprised to see. You want to talk to a stranger, but you find yourself suddenly paralyzed when you approach that person. The withdrawal system can quickly shoot up to full power,19 overtaking the slower (and generally weaker) approach system.