Why Do We Dream? An Evolutionary Biologist Explains (Hint: Scientists Still Can’t Agree On An Answer)

Scientists still do not agree on why we dream despite detailed knowledge of REM sleep.

The threat simulation theory, proposed by Antti Revonsuo in 2001, argues dreams rehearse dangerous situations.

A 2006 analysis of 212 recurrent dreams found about 66% contained threats and 54% showed realistic defensive responses.

A 2009 computational model by Qi Zhang links sleep to memory reprocessing that may reorganize experience and support learning.