How do institutions like religion and politics play a role in creating or maintaining beliefs and preconceived notions?

Religion and politics both have the ability of creating and maintaining a set pattern of beliefs which are resistant to change or questioning, even in the face of evidence that contradicts their preconceived convictions. 

In a religious system, there are accepted holy books and religious authority figures that establish what is considered true, and to question any of those accepted truths may be branded as heresy. Religious history contains a number of examples of religious institutions resisting and opposing other forms of knowledge, such as that produced by scientific inquiry. Galileo, for instance, was pressured by the Inquisition of the Roman Catholic Church to stop publishing ideas about the solar system that contradicted the church's assertions that the earth stands at the center of all of God's creation. 

Politics can function in a similar way when political perspectives become entrenched and resistant to any self-analysis or change. In the current political climate in the United States, conservatives (mainly on the Republican side of the aisle) see social programs run by the government as bad ideas that they battle against, while liberals (mainly on the Democratic side of the aisle) believe the government has a duty to carry out social programs for the common welfare of all citizens. The two sides can become as entrenched in their political beliefs as religious adherents are in theirs, and thus they become unwilling to compromise or work with others that are on the opposite side of the political spectrum.