Imagine you could live in one of two worlds where the price of goods and services were the same. In the first world, you earn £50,000 a year, while other people get £25,000. In the second, you earn £100,000, while others get £200,000. Which would you choose? If it’s the first world, you’re not alone. Researchers at Harvard University found that half of people would turn down what was effectively a doubling in salary if it meant they out-earned those around them.