After decades of research and speculation, the reasons for dreaming are still unknown. There are many theories, of course, as Harvard psychologist Deirdre Barrett notes as she reviews the most prevalent evolutionary theories for why we dream:
- Brain Conditioning
- External Vigilance
- Threat Simulation
- Costly [Genetic] Signalling
- Problem-Solving
The article also notes how many “notable figures from all walks of life (including scientists) [have] arrived at their groundbreaking discoveries and insights through dreams”. To Barrett, this suggests that “a simple brain conditioning explanation for the existence of dreaming is shortsighted”.