In the early to mid-1990s,researchers had more than 10,000 people ages 18 to 64 keep diaries for a 24-hour period and detail everything they did.

• 20世纪90年代早期至中期，研究人员让10000多名18岁至64岁的人每天记日记，详述他们24小时内做的每一件事。