When I tilt my wide lens up, buildings become trapezoidal. Why don't they do this when I tilt my eyes up?

When I tilt my wide lens up, buildings become trapezoidal. Why don't they do this when I tilt my eyes up? Is my brain straightening the lines, or is something else going on? Also, if my brain is straightening the lines, how do I trick it into showing me what I'm actually seeing? via /r/photography https://ift.tt/2w0KVo4