Much of what we know about human thought and behavior has emerged thanks to various psychology theories. For example, behavioral theories demonstrated how conditioning can be used to learn new information and behaviors. Psychology students typically spend a great deal of time studying these different theories. Some theories have fallen out of favor, while others remain widely accepted, but all have contributed tremendously to our understanding of human thought and behavior. By learning more about these theories, you can gain a deeper and richer understanding of psychology's past, present and future.