It started in the 1990s when the Americans with Disabilities Act was passed in the US, making sure that all lifts stayed open long enough so that people with disabilities could enter. Only US firefighters and repairmen can use the buttons to speed up the door-closing process if they have a code or special keys.

　　But to normal lift riders, the buttons aren't completely useless. According to psychologists, fake buttons can actually make you feel better by offering you a sense of control.

　　"A sense of control is very important. It reduces stress and increases well-being," said Ellen J. Langer, a psychology professor at Harvard University. Experts also added that a lot of buttons that don't do anything exist in our lives for this same purpose.

　　For example, pedestrian(行人) crosswalk buttons don't live up to their names either. Pressing them used to help make the traffic signals change faster, but that was before computer controlled traffic signals were introduced.

　　But psychologists found it interesting that even when people are aware of these little "white lies", they still continue to push fake buttons because as long as the doors eventually close, it is considered to be worth the effort.

12. What was the author's main purpose in writing the article?

A. To analyze the functions of fake buttons.

B. To describe some different kinds of fake buttons.

C. To explain the advantages and disadvantages of fake buttons.

D. To explore people's different habits when it comes to pushing buttons.

13. What can we learn about the "close" buttons on a lift in America?

A. They work when people press them hard.

B. They were designed for a sense of control.

C. They never speed up the door-closing process.

D. They take the safety of the disabled into account.

14. What can we infer about pedestrian crosswalk buttons?

A. They help computers work faster.

B. They can control the traffic signals.