ELI5 Pillows - do humans really need them?

What happens if we sleep without them? Does it cause long term spinal problems if you sleep without one regularly? Why do babies seem to do fine without a pillow?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: starrdust322, agentelman, open_door_policy and philosophile42 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]