I have two little boys, aged 4 and 6. They both love to have rides in the car, and they much prefer the FRONT seat. So we make them take turns. The 4 year old always wants his turn immediately. He gets upset when it is his brother's turn. But the 6 year old has realised that if his brother rides in the front this time, it's his turn next time. He still has something to look forward to, when the 4 year old has already 'consumed' his ride. From this I infer that the normal human will begin as a liberal, expecting immediate gratification of his wants, and at some point between the age of 4 and 6, mature into a conservative who is able to defer immediate gratification and utilise will power.