This human capacity to distinguish the here-and-now from the here-and-not-now showed up at least 50,000 years ago in cave paintings. These constitute the first evidence of any species on earth being able to explicitly represent the distinction between what is here and what was here. In other words, those early cave-dwelling Picassos, through the very act of painting, were making a distinction about time and place and objects, an advanced cognitive operation we now call mental representation