“In the earliest phase of this evolutionary process (probably during the Pliocene epoch) we had a kind of involuntary imagination. At this time, hominin waking life might have been closer to the free associations of our contemporary dream life. Our ancestors could obviously perceive a lion on the savanna, but random memory images of lions might also rise up unpredictably while engaged in daily work. Next, during the Pleistocene, a semi-voluntary imagination arose, like we find in real-time hot cognition (still accessible in our contemporary improvisational creativity).”