Fake news includes:

Information we consume is like the food we eat. If it's junk, our thinking will show that.

It has four distinct features:

The trickle of information pollution, like air pollution, builds up over time. The more we are exposed to it, the more likely we are to pick up false beliefs that are hard to get rid of.

The typical explanation is that our brains take shortcuts to save energy:

People that spread propaganda rely on repetition to change the beliefs and values of other people.