Motivational psychology, passion, motivation, drive. Big words, tremendous feelings. I always wanted to understand where these forces come from.
Motivation can be difficult to find every now and then. But there is more to it than just finding the drive and initiative to do something. So I’ve done a lot research and found out the most important theories than have been developed on motivational psychology.

Instinct Theory: a biological theory. The Instinct Theory describes that motivation is inherent and completely biological. This could mean that your direction comes from your pure nature. For example, it would be your instinct to react to a particular situation and act on it. Even babies are motivated to cry when in trouble because they are reacting to something that is bothering them. Animals demonstrate this theory in the way they are motivated into living. Birds, wolves, lions, and other animals are preprogrammed into creating their homes and caring for their young without any question on why they are doing it. Naturally, it is because of the Instinct Theory that motivates them.
Drive Reduction Theory: although seemingly similar to the Instinct Theory, Drive Reduction Theory says certain biological feelings may motivate you to satisfy himself. Clark Hull examined having states of being hungry or thirsty motivate us to act on it and have a bite to eat for example. Feeling tired may drive you to get some rest as well. These feelings are necessary to be satisfied—we are therefore, motivated by them.
Psychoanalytic Theory: deals entirely with the subconscious mind. According to Sigmund Freud, everything we do is because we want to survive or prevent our own destruction. The Psychoanalytic Theory delves more into the subconscious. Just like how you know that having a job will not only sustain you financially but will also give unconscious opportunities like finding the right partner or giving children the right neighborhood to grow up in. Being secure as Freud explains is the root of all motivation whether you know it or not.
Arousal Theory: similar to the Drive Reduction Theory but this time, to a higher level and not just for feelings of hunger or thirst. According to the theory, motivation is found in finding a comfort level in anything emotion, intellectual, or physical.
Humanistic Theory: which you may have encountered at some point in your life. For whatever need, the theory discusses how people are driven to reach their maximum potential. These pertain to being motivated to reach anything from Maslow’s Hierarchy of Needs—whether it be physiological, safety, belonging, esteem, or self-actualization needs.