Introduction
The emotions which we experience everyday can be fundamentally explained due to chemicals which our brains produce. The outcomes of our emotion (facial expressions, reflexive noises such as a loud cry for help, or even just feelings of anger or happiness) are natural results. The emotions in response to stimuli have trivially evolved from the time of the caveman to the present day; our emotions and those of an ancient human are very similar.

Sects of Emotion
To understand human emotion it is easier to divide it into two main senses:
(1) Emotional expression for communication and social coordination
a. External aspects of emotions
i. A loud scream for help
(2) Emotion for organization of behavior (action selection, attention and learning)
a. The feeling of self-betterment
b. Competition is a main cause