Everyone has a system of beliefs that, together with various other levels of memory contents, establishes a personal ground truth. That ground truth serves as a

Everyone has a system of beliefs that, together with various other levels of memory contents, establishes a personal ground truth. That ground truth serves as a base line when our brain processes newly incoming information. Our brain is amazingly good at dismissing incoming data if it contradicts our ground truth, or giving such data a different spin so it fits our ground truth better. If our brain stopped doing that, and started letting any information pass unfiltered, a single glitched nerve impulse may end up being perceived as a hallucination or worse. Our brain’s habit of ironing out glitches may have had a real evolutionary benefit: as our brain keeps filtering, we can afford to own less-than-perfect senses instead of having to pump endless amounts of energy into making them perfect. That may have allowed our ancestors to save a lot of energy, giving them a head start in times of evolutionary pressure (such as famines). I’m not a behavioral psychologist but I’d find it plausible if this behavior applied to other brain functions as well, such as dealing with incoming facts and comparing them to our personal ground truth. So our brain may dismiss anything it can’t sufficiently match with that ground truth.