A、Sunrise times across British time zones. B、Sunrise times across American time zones. C、Sunset times across British time zones.

We all know sleep matters for job performance as sleep affects attention, memory and cognition—important factors in the workplace. But (22)striking new research suggests the effect of additional sleep has a high monetary value. A paper from Matthew Gibson of Williams College and Jeffrey Shrader of the University of California at San Diego says (23)a one-hour increase in average weekly sleep increases wages by 1.3% in the short run and 5% in the long run.
Don’t think you can start to sleep more and you will instantly make more money. It’s more about the subtle interplay between how people schedule their lives, how much time they have available to sleep and how that affects worker performance and, ultimately, earnings. (24)To investigate how sleep affects worker wages, the researchers took advantage of a kind of natural experiment—sunset times across American time zones. They find that a one-hour increase in average weekly sleep in a location increases wages by 1.3% in the short run, which include changes of less than a year, and 5% in the long run. By moving to a location where a sunset is one hour earlier, a worker will make an additional $1,570 a year. A county that experiences a sunset one hour earlier has on average a 6% higher median home value, about $7,900 to $8,800, they say.
Not all of these wage differences are due directly to sleep, the researchers caution. (25)Some could be due to the cumulative influence of other people. If the workers around you are made slightly more productive by sleeping better, that could make your work more productive, too.
Questions 22 to 25 are based on the passage you have just heard.
22.What does the new research suggest?
23.What did a paper from the University of California say?
24.What natural experiment did the researchers take advantage of?
25.What else could lead to the wage differences except sleep?