阅读理解。阅读短文，从每小题给的四个选项中，选出能回答所提问题或完成所给句子的最佳答案。 Have you ever had the strange feeling that you were being watched? You turned around and, sure enough, someone was looking right at you!
Parapsychologists (灵学家) say that humans have a natural ability to sense when someone is looking at them. To research whether such a “sixth sense” really exists, Robert Baker, a psychologist (心理学家) at the University of Kentucky, did two experiments.
In the first one, Baker sat behind unknowing people in public places and stared at the backs of their heads for 5 to 15 minutes. The subjects（受试者）were eating, drinking, reading, studying, watching TV, or working at a computer. Baker made sure that the people could not tell that he was sitting behind them during those periods. Later, when he questioned the subjects, almost all of them said they had no sense that someone was staring at them. For the second experiment, Baker told the subjects that they would be stared at from time to time from behind in a laboratory setting. The people had to write down when they felt they were being stared at and when they weren't. Baker found that the subjects were no better at telling when they were stared at and when they weren't.
Baker concludes that people do not have the ability to sense when they're being stared at. If people doubt the of his two experiments, said Baker, “I suggest they repeat the experiments and see for themselves.”
