他们叫学生在几件 物品之间作如选择，如两张不同的CD 或二种口味的果酱。

They asked students to choose between things like a pair of CDs or two flavors of jam.

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Then you see way back in human histories figures like this where people had to go hunt for their food, and of course there was danger involved in this.

让我们回到人类演化史上,如这张图所示,人们不得不去狩猎觅食,当然,这是非常危险的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选