How we got here
The stimulus changed faster than your brain
Pornography always existed. What changed — in barely two generations — is access: from scarce and effortful, to infinite, free and instant.
1950s–70s
Magazines
Paper. You had to go buy it, hide it, wait for the next issue. The stimulus was limited and took effort to get.
1980s
The VHS tape
The image moves and comes into the home. Even so it was a finite catalog: a few tapes played on repeat.
1990s
Dial-up internet
Variety arrives, but slowly: images that took minutes to load. Friction still put on a natural brake.
2006
Tube sites
Free streaming, endless, one click away. With constant novelty the Coolidge effect kicks in — a mechanism that in animal models reactivates the dopamine spike with each novelty. And here the novelty never runs out.
2010s
The smartphone
Access becomes 24/7 in your pocket, private and without barriers. Some surveys place first exposure around ages 11–13, with wide variation across studies.
Today
Infinite scroll and algorithms
Ethologist Nikolaas Tinbergen (Nobel 1973) called artificial, exaggerated versions that hijack an instinct a “supernormal stimulus.” Endless scroll, optimized by algorithms, is exactly that at industrial scale.
0billionvisits in a single year, to a single site, according to its own annual report (Pornhub, 2019).
The core idea
It isn’t weakness. It’s a mismatch.
For almost all of human history this stimulus was scarce. In two generations it became infinite, free and instant. Your reward circuit didn’t evolve for this. That it’s hard says nothing about your willpower — it says everything about the mismatch between an ancient brain and a new technology.