Sometimes you know things about people the first time you see them, for example, that you want to be friends with them or that you don't trust them. But perhaps this kind of intuition isn't as hard to explain as it may seem. For instance, people give out their body language signals all the time. The way you hold your body, head and arms tells people about your mood. If you hold your arms tightly at your sides, or fold them across your chest, people will generally feel that you are being defensive. Holding your head to one side shows interest in the other, while an easy, open posture indicates that you are self-confident. All this affects the way you feel about someone.

Also, a stranger may remind you of a meeting with someone. This may be because of something as simple as the fact that he or she is physically similar to someone who treated you well or badly. Your feelings about a stranger could be influenced by a smell in the air that brings to mind a place where you were happy as a child. Since even a single word can bring back a memory such as that, you may never realize it is happening.