Your friend is right; the brain has a beautiful system called neural/sensory adaptation which eventually leads to the same patterns being less stimulating and e

Your friend is right; the brain has a beautiful system called neural/sensory adaptation which eventually leads to the same patterns being less stimulating and even ignored. Off-topic, but I wonder if some people with autism lack this mechanism and are therefore constantly overwhelmed by sensory input. The brain is such a beautiful, but delicate hack of evolution.