Chapter 4 is about sensation and perception. Here is an interesting concept called extrasensory perception (ESP). According to the textbook, extrasensory perception is divided into three types, which are precognition, telepathy and clairvoyance. Precognition is an ability to predict what will happen in the future. Telepathy is like mind reading. People with clairvoyance have "x-ray" eyes, which help them detect hidden things. The three types of phenomena sound like supernatural powers. However, the examples of extrasensory perception are everywhere in daily life. I went to Madison during the winter break for the first time. One night, I went out to buy some fruits but I lost my way. I did not bring my phone and I could not find anyone for help. I was about to cry. Interestingly, I felt I was under the same circumstances in one of my dreams. I found myself standing in a strange street and I was so scared that I woke up immediately. This experience was amazing and unbelievable. This might be an example of precognition and it is called déjà vu referred to a subsequent chapter. Another example of precognition mentioned in the textbook is some people know what others are going to say. I have to admit it happens a lot but as the textbook explained, this kind of situations only happens to intimate people. A similar case would be my mother even gets what I am saying when I brush my teeth at the same time. None of my words are pronounced correctly. I do not think her right understanding is due to extrasensory perception. However, it is because my mother knows me so well that she understands me by my body language and facial expressions. Perhaps that people you just meet can also have an idea about what you mean or going to say. Yet as the book says, you do not notice times they have no idea happen much more often.