He uses his personal experience to explain this concept.
First, he says that some measures were needed to manage patients who did not follow rules. So a local drug treatment center decided to give patients who behaved well more time to talk on the phone. However, this policy was not effective because most patients did not value more time to use a phone. As a result, the situation at the center did not improve at all.
Second, he mentions that he helped the center institute a token reward system. Every patients received 1 token each day without a rule violation. The coin could be exchanged for a chose reward. Because this was something to all patients, they are motivated to follow the rules. The result was successful.
This example demonstrates how a token reward system can be effective.
5. The man's problem is that he has to finish a research paper but cannot find a quiet place because the library is under maintenance work.
The man and the woman suggest two possible solutions to the problem. The first suggestion is to go a cafe off campus. The second suggestion is to complain to a maintenance supervisor.
I think the first suggestion is better for him. This is because the supervisor won't be less likely to accept the man's opinion. Also even though the cafe is inconvenient and far away, the man would not look for quieter places than the cafe.
For these reasons, I would recommend the first option for him.
6. The professor explains how bats hunt for food by giving two examples.
First, she describes aerial hawking in which bats hunt prey and consume it while in flight. This way is usually used by smaller bats. Each time bats try this hunting, only small prey is captured so bats need to keep hunting until they get enough food. Also aerial hawkers depend on echolocation to discern the location of the prey.
Second, she describes perch hunting in which bats hang upside down from the perch and wait around for prey to come near them. Larger bats often make use of this method. And There is no need for them to hunt often because the prey that is taken is large enough. As bats wait until a prey comes close to them, they only utilize the sense of smell and eyesight to detect.
These examples demonstrate two ways that bats use to hunt for food.