My final year at University was spent studying Experimental Psychology. As part of this I studied how the eye & brain turns light rays into vision. It's pretty obvious when you think about it, but this quote from a lecturer made me sit back and think about just how cool the brain is.
"the light rays aren't coloured".
In other words, nothing in the world exists as we perceive it. Colour only exists in our head. The same applies to the other senses...there is no smell, just chemicals in the air, sounds are just bits of rhythmically moving air.
All marketing happens in that brain too - impacting on a complex associative network of memory and the cognitive processing of information.
Worth remembering when someone next uses the word "consumer" and talks about "doing marketing to someone".