The progress principle is the science behind the famous saying “it’s the journey, not the destination, that counts.” In other words, more happiness will be achieved in the steps that lead up to a goal than in the final step of reaching the goal itself. In The Happiness Hypothesis, Jonathan Haidt explains the logic behind this. Say it takes 10 steps to reach a goal. Why would going from step 9 to step 10 bring more happiness than all the other steps combined?

To give a personal example, I really wanted to get a first in my psychology degree, but I’d screwed up the first year and a half, work-wise, so I needed to make up for that. I worked hard in the final three semesters, my marks got better and better, and my average started to rise up to the magical 70% target. The final grade I got, for my dissertation, pushed me just over the 70% mark. But when I got that result back, I wasn’t jumping for joy. If I felt anything it was more like relief at that point. In fact, thinking back on the experience, I scarcely remember getting my final grade.

This isn’t always the case, and some goals will have you jumping around. But speaking generally, happiness results from taking a step in a beneficial direction, but not from standing still at any particular point. The feeling of the final step is weaker than the previous steps, because the part of the brain associated with positive emotions (the left prefrontal cortex, as we discussed earlier) reduces its activity once you reach a goal. This isn’t such a bad thing; we need the progress principle so that we stay motivated to pursue goals. If all the happiness came at the destination rather than the journey, where would our motivation come from?