They asked their 600 volunteers first to rate their general happiness, report their annual income and detail their monthly spending including bills, gifts for themselves, gifts for others and donations to charity.

• 研究人员让600名志愿者评价自己的总体幸福感，报告年收入以及详细的月支出情况，包括应付账单、为自己及他人购买礼物支出以及慈善捐献。