Emotions are what people feel. They are very ancient, and can be seen in all mammals.
Emotions are caused by a complex mixture of hormones and the unconscious mind. Only with great difficulty can we control our emotions by conscious effort. They cause mammals to change behaviour according to changes in their situation. In our case, they sometimes run against our attempt to live our lives in a logical way.
A scientific definition is not simple; over 90 definitions have been offered by experts.[1] A definition of emotion needs to include three things:
Here is one definition:
In physical terms, emotions involve body systems which have operated for hundreds of millions of years. These are the hormone system, the autonomic nervous system and the 'lower' brain centers (hindbrain and midbrain).