Fear is an emotion made by a particular part of the brain. This part ① rarely scans information from your senses — the things you see, hear, and feel. When your brain recognizes a ② similar situation to one stored as a memory, however trivial it is, it brings up those same feelings that are attached to the memory. It stores memories of danger and whether what you did (like running away) helped or made things ③ worse. These memories help the brain make very ④ fast decisions about how to respond to threats.