Thinking about the good old days triggers neurochemicals that make you feel good. You might reach the conclusion that life was better in the past. But if you had actually lived in the past, you would not have liked it.
Your sex partners would have been chosen for you if you had lived in the past. Your elders would have obligated you to partners who benefited them.
You would have felt dirty all the time if you lived in the past. Without hot running water or toilet paper, you would have had that camping-trip feeling your whole life. Your food would have been laced with vermin droppings and your drinking water would bring intestinal worms.
You would have been scared all the time if you lived in the past. Death would have snatched those around you, and people would explain this with theories that made it scarier. You wouldn't have left your village if you lived in the past because it was too dangerous. Home wasn't safe either because of invasions, famines, and routine domestic violence.
Today, we're safer, cleaner, and freer to choose our sex partners, but people are convinced that things are awful. Why do people think life was better in the past?
Because your brain focuses on what you lack, and takes for granted what you have. If you feel you lack leisurely dinners with friends, and you imagine people having them in the past, then the past seems better regardless of the facts.
When you feel you lack something, your brain rings the alarm that says your survival is threatened. Obviously, lacking friendly dinners is not life-threatening, but if it's the biggest lack on your mind, your brain processes it with equipment that evolved to confront survival challenges. Your present lacks feel urgent while the lacks of the past are just historical abstractions.
Think you're too smart for this bias? Consider these physiological nitty gritties:
1. Monkeys experienced dopamine spikes when experimenters rewarded the monkeys with juice instead of leaves. But dopamine levels soon fell, even while the monkeys kept getting the juice. Then the experimenters switched back to leaves, and the monkeys exploded with rage. Though content with the leaves at the start, losing something triggers icky chemicals, even when the losses are insignificant. Gaining something triggers happy chemicals, but only at first. A steady stream of new rewards is what it takes to trigger a steady stream of happy chemicals. This is why people can feel bad amidst lives that are so good compared to the wildest dreams of their ancestors.
2. Pain gets the brain's attention immediately. Pain was a big part of daily life in the past due to hunger, injury, disease and violence. Today's life holds less physical pain, so social pain gets your attention. If a social snub in the cafeteria is the worst pain you suffer, then to your brain it is a survival threat of the first order. We process social pain with systems that evolved to process survival threats, so we scan for social snubs instead of sitting back and enjoying our comfortable lives.
3. Visceral experience triggers more neurochemicals than historical facts on a page. For example, a neglected public rest room triggers more disgust than reading about the pit toilets, chamber pots and open sewers of the past, because you have real sensory experience of today's dirty bathroom. Today's suffering seems more intense than the suffering of the past because you feel it directly. People believe life is more stressful these days because they did not actually feel the stress of those days.
When your life is frustrating, you may take comfort in thoughts of a glorious past. When you do, you are stimulating happy chemicals that are real. That makes it easy to believe that a better world lies in other times and places. It's easy to ignore all the good in the present – until you understand your own operating system.