Typically--I don't know for those particular children, but typically on those tasks three-year-olds and young four-year-olds tend to fail, and around the age of four or five kids tend to succeed.

我不太了解那些特定儿童的情况,但一般来讲,三岁和刚进入四岁的儿童,通常会在这些任务中失败,而四岁或是五岁左右的儿童则通常会成功

耶鲁公开课 - 心理学导论课程节选

Ads in newspapers, like this one in Charleston, would read, "Negroes wanted. I am paying the highest cash prices for young and likely Negroes, those having good front teeth and being otherwise sound."

报纸上的广告,比如查尔斯顿市的这一则,是这么写的,"诚购黑奴,本人愿付最高价格,购买年轻可靠之黑奴,需有整洁的牙齿以及悦耳的声音"

耶鲁公开课 - 美国内战与重建课程节选