I asked psychologist Tom Stafford, who writes the Neurohacks column for BBC Future about the gap. "Squaring what works for you and what the science says is difficult because happiness is a complex object," he told me. "There will be local variations due to individual personality, so we've immediately got a reason for expecting a gap between the science -- which tends to work with group averages -- and any one person's experience."The interesting general question, to me, is when do we trust our experience and when do we listen to science," Stafford added. "Obviously some things we don't need science for ('Does dropping a rock on my foot hurt?'), and some things we do ('Is smoking bad for my health?'). Happiness, I'd argue, is in between these two cases."