evolution-of-dreams
Explanation
The Joke
In the first panel, a woman asks a man: "You ever wonder why we don't remember dreams?" He replies: "It's weird. You wake up with something vivid and it fades in a minute or two. Poof. Gone." The comic then jumps to "100,000 Years Earlier" where a cavewoman excitedly tells a caveman: "We gotta move! A great spirit came to me and told me you all the species on last night's dirt!" -- essentially, she had a vivid dream that she mistook for a divine vision, and she is ready to uproot the tribe based on it.
The Humor
The comic offers a humorous evolutionary explanation for why humans quickly forget their dreams. In prehistoric times, a person who vividly remembered their dreams and treated them as real divine messages would make terrible, irrational decisions -- like forcing their tribe to relocate based on dream content. Natural selection would therefore favor individuals who forgot their dreams quickly, since those people would not constantly confuse dream experiences with reality. The joke takes a genuine neuroscience mystery (why dream recall is so poor) and gives it a practical evolutionary "just-so story" explanation. It is a classic SMBC move: using evolutionary logic to explain a quirk of human psychology in a way that is both plausible-sounding and absurd.