Your brain creates your beliefs from what you are taught and from what you learned. These are two different concepts because many times what you are "taught" is opposite from what you "observe" around you and consequently "learn" what you observe and not what you were taught.
This may include cellular memory from biologicala ncestors, role-modeling by adults around you, interactions with people you admire or don’t, your own life experiences, what you watch on TV and movies, what you read, what political or religious leaders tell you versus what you observe . . .
Who or what do you believe? Who or what do do you believe “in?” More tomorrow.