Question 23 is based on the recording you have just heard.

Recording Three

听力原文

       I’m a psychology professor at the University of British Columbia. (22) I specialize in Cultural Psychology, examining similarities and differences between East Asians and North Americans.

Our research team has been looking at cultural differences in self-enhancing motivations, how people have positive feelings towards not only themselves but things connected to themselves. For example, when you own something, you view it as more valuable than when you don’t own it. It’s called the “endowment effect”. The strength of that effect is stronger in Western cultures than in East Asian cultures. So we’ve been looking at other ways of seeing whether this motivation to view oneself positively is shaped by cultural experiences.

       We’ve also started to look at how culture shapes sleep. We are still in the exploratory stages of this project—(23) although what’s noteworthy is that East Asians on average sleep about an hour and a half less each night than North Americans do. And it’s not a more efficient sleep, not like they’re compressing relatively more value out of their hours. Other studies have found that even infants in East Asia sleep about an hour less than European infants. So we’re trying to figure out how culture shapes the way you sleep.

       Our experiment does not take place in a sleep lab. (24) Instead, we lend people motion-detecting watches, and they wear them for a week at a time. Whenever they are not having a shower or swimming, they keep it on. These kinds of watches are used in sleep studies as a way of measuring how long people are sleeping, how efficient their sleep is, and whether they are waking up in the night. Ideally, I’d like to take this into a controlled lab environment. We’ll see where the research points us. We usually start off with the more affordable methods, and if everything looks promising, then it will justify trying to build a sleep lab and study sleep across cultures that way.

       Why do we study sleep? (25) Sleep is something that has really been an unexplored topic cross-culturally. I’m attracted to it because culture isn’t something that only shapes the way our minds operate; it shapes the way our bodies operate too, and sleep is at the intersection of those.

23. What does the speaker say about North Americans?

解析：C。录音中间部分指出，值得注意的是，东亚人每晚的平均睡眠时间比北美人少一个半小时。也就是说，北美人比东亚人睡眠时间长，故C选项为正确答案。