Question 21 is based on the recording you have just heard.

Recording Two

听力原文

    In last week’s lecture, we discussed the characteristics of the newly born offspring of several mammals. You probably remember that human infants are less developed physically than other mammals of the same age. (19) But in today’s lecture, we’ll look at three very interesting studies that hint at the surprising abilities of human babies.

    In the first study, three-year-olds watch two videos shown side by side, each featuring a different researcher, one of whom they’d met once, two years earlier. The children spend longer watching the video showing the researcher they hadn’t met. This is consistent with young children’s usual tendency to look longer at things that aren’t familiar. And really this is amazing! It suggests the children remembered the researcher they’d met just one time when they were only one-year-olds. Of course, as most of us forget memories from our first few years as we grow older, these early long-term memories will likely be lost in subsequent years.

    Our second study is about music. For this study researchers played music to babies through speakers located on either side of a human face. They waited until the babies got bored and inverted their gaze from the face. And then they changed the mood of the music—either from sad to happy, or the other way around. This mood switch made no difference to the three-month-olds, (20) but for the nine-month-olds, it was enough to renew their interest and they started looking again in the direction of the face. This suggests that babies of that age can tell the difference between a happy melody and a sad tune.

    (21) Our final study is from 1980, but it’s still relevant today. In fact, it’s one of the most famous pieces of research about infant emotion ever published. The study involved ordinary adults watching video clips of babies nine-months or younger. In the video clips, the babies made various facial expressions in response to real life events, including playful interactions and painful ones. The adult observers were able to reliably discern an assortment of emotions on the babies’ faces. These emotions included interest, joy, surprise, sadness, anger, disgust, contempt, and fear.

    Next week, we’ll be looking at this last study more closely. In fact, we will be viewing some of the video clips from that study. And together, see how well we do in discerning the babies’ emotions.

21. What is the 1980 study about?         

解析：B。录音中提到，最后是一项1980年的研究，但这项研究在今天仍然有借鉴意义，而在婴儿情绪研究领域，这是有史以来最著名的研究之一，也就是说这项研究是关于婴幼儿情绪的，故B项正确。A项利用facial expressions设置干扰，但录音中出现facial expressions是表示婴儿对各种事件作出反应时的面部表情，这是服务于研究主题的，并不是研究主题本身，故排除。C项利用interaction设置干扰，但原文说的是婴儿对playful interaction所作出的反应，并不是指与成人互动，故排除。D项内容在录音中未提及，故排除。