TOEFL Speaking Task 4 Practice 004Science

Narrator:Listen to part of a talk in a psychology class.

Professor:Children's emotional development depends a lot on their earliest relationships, which is why the bond between children and their parents or caregivers is so important. Psychologists have always been curious about how this bond is formed. What causes young infants to become attached to their caregivers? Psychologists used to believe that babies became attached to the person who feeds them. Makes sense, right? Babies depend on others to provide nourishment to keep them alive. But most psychologists now believe otherwise. Today most psychologists think that a warm and loving touch is actually more important than feeding. So, what's the basis for this belief? Why do psychologists think food matters less than touch when it comes to creating emotional bonds between infants and their caregivers? Well, there was a famous experiment. ... It was done using baby monkeys-which are a lot like human babies. Researchers provided each baby monkey with two substitute, or replacement, mothers-two contraptions made out of wire, each the size and shape of an adult monkey. But-and this is important-one of the contraptions was wrapped in foam and covered with a super-soft cloth. This was called the cloth mother. The other wasn't covered with anything; it was just bare metal wire. This was the wire mother. Each baby monkey was given both types of mother. However, some of the baby monkeys were fed only by the wire mother, while others were fed only by the cloth mother. But when it wasn't feeding time, all of the monkeys could climb on, or cuddle with, or cling to whichever mother they wanted to. So, which mother did the baby monkeys become attached to? Well, all of the baby monkeys spent most of their time-when they weren't eating-with the cloth mother. They held on to her and ran to her whenever something startled them. No matter which mother fed them, all of the baby monkeys preferred the cloth mother.