Answer:
Hippocrates
Explanation:
Hippocrates believed that human moods were caused by the lacking or absence of certain fluids called humors, the humors were the ones that dictated someone´s personality and how he reacted to certain things, there were basically 4 types of humors and a person often belonged to one of those four personalities or he could be a mix of two of them, this is one of the oldest theories on human behavior.
