Behavioral psychology
Psychology
42 rabbit holes · 19 people exploring
Common starting questions
- What did patient H.M. teach us about memory?
- How long does it really take to build a habit?
- Was Three Mile Island caused by bad design?
- Do .99 prices actually work?
- Was there ever a Sinbad genie movie?
Rabbit holes
- why Japanese train staff point at things and say them out loud
Lin Chen · 4 sources
- H.M., the man who couldn't make new memories
Lin Chen · 6 sources
- Thinking, Fast and Slow has a chapter that didn't age well
The 'Florida effect': students who unscrambled words related to old age supposedly walked more slowly afterwards. The book told readers they basically had to accept findings like this. A 2012 replication only found the slower walking when the experimenters expected it.
Valentina Russo · 5 sources
- it doesn't take 21 days to form a habit
Lin Chen · 5 sources
- Three Mile Island was partly an interface problem
A relief valve stuck open, but the light on the control panel only showed that the valve had been told to close, not whether it actually had. The operators trusted the light while alarms went off by the dozen. Afterwards the industry got a lot more serious about control room design and human factors.
Pete Lindgren · 6 sources
- The Dancing Plague of 1518
Hundreds of people in Strasbourg danced for days. The authorities' fix was to build a stage and hire musicians so they could dance it out, which made it worse.
Yuki Tanabe · 5 sources
- why everything costs $X.99
There's a popular story that odd prices were invented to make cashiers open the register and give change instead of pocketing a round-dollar sale. Fun, but nobody seems able to prove it. Left-digit bias is the part that holds up: $4.99 reads as 'four something'.
Tomás Rinaldi · 5 sources
- Shazaam: the 90s genie movie that never existed
Yuki Tanabe · 6 sources
- the decoy effect, and why it's weaker than the books say
The famous example: web-only subscription $59, print-only $125, print plus web $125. Nobody wants print-only, but its being there makes the bundle look like a steal.
Pete Lindgren · 5 sources
- willpower isn't a battery (probably)
Wren Abernathy · 6 sources
- 800 people guessed an ox's weight and the median was within 1%
1906, a livestock fair in Plymouth. Galton collected the tickets from a weight-guessing contest, supposedly expecting to show how bad ordinary people were at judging. The median guess was 1,207 lb. The ox was 1,198. It only works if people guess independently though; once they can see each other's answers it falls apart.
Pete Lindgren · 5 sources
- why the Mac menu bar is glued to the top of the screen
Jonah Feld · 6 sources
- Ebbinghaus memorized nonsense syllables for years so we'd have the forgetting curve
In the 1880s he tested himself on lists of meaningless syllables and measured how fast he forgot them. Basically a one-person study, and a 2015 replication found pretty much the same curve. Steep at first, then flattening, and every review slows it down.
Jonah Feld · 7 sources
- Sans Forgetica, the font that was supposed to help you remember
Noor Rahman · 5 sources
- are pro gamers really past their peak at 24?
Noor Rahman · 5 sources
- the '7 plus or minus 2' rule is about something else
Someone at work said nav menus should have max 7 items 'because of Miller's law', so I read the actual 1956 paper. It's a funny, rambling essay about information channels and memory span. It says nothing about menus.
Chidi Eze · 6 sources
- the invisible gorilla (one of the classics that actually replicates)
Count the passes by the players in white. In the original 1999 study, roughly half of people missed a person in a gorilla suit walking right through. I'd seen it before so I caught the gorilla, then their follow-up video got me with something else. You see what you're looking for.
Hannah Kim · 5 sources
- JCPenney tried honest pricing and customers hated it
In 2012 they dropped most of the coupons and constant sales and just charged a fair price up front. Sales fell hard, the CEO was out within about a year and a half, and the sales came back. Turns out a lot of people don't want a low price, they want to feel like they beat the price.
Tomás Rinaldi · 5 sources
- the Dunning-Kruger graph everyone shares isn't from the paper
The 'Mount Stupid' curve, where confidence spikes at low knowledge, is a meme, not a figure from the 1999 paper. The actual result: people in the bottom quartile overestimated their scores a lot, and people at the top slightly underestimated theirs.
Dev Malhotra · 5 sources
- if a door needs a PULL sign, the door is wrong
Hazel Park · 6 sources
- Kahneman's team estimated two years. it took eight
His team writing a school curriculum all guessed about two years. Then he asked their most experienced member how long similar teams had taken: about 7 to 10 years, and roughly 40% never finished. They kept going anyway. It took eight years, and by then nobody used it.
Arjun Pillai · 6 sources
- The Chinese Room argument
Pete Lindgren · 5 sources
- the Monopoly man doesn't have a monocle and I'm not ok
There's a 2022 study on the 'visual Mandela effect': people consistently misremember specific details of famous images (Pikachu's tail, the Monopoly man's monocle) in the same wrong way, even when they've seen the real thing many times. Then Loftus, and how easily memories get edited after the fact.
Lin Chen · 6 sources
- Houston's airport fixed baggage complaints by making people walk farther
The story (from a 2012 NYT piece): people complained about waiting at baggage claim, so the airport moved arrivals farther from the carousels. Same total time, but now most of it was spent walking, and the complaints mostly stopped.
moth · 4 sources
- crows hold grudges against specific humans
Researchers in Seattle wore a specific mask while trapping crows. Years later, crows (including ones that were never trapped) still mobbed anyone wearing that mask. They taught each other.
Aroha Williams · 5 sources
- ELIZA fooled people in 1966 with ~200 lines of code
Weizenbaum's own secretary asked him to leave the room so she could talk to it privately. He was horrified, not flattered.
Ludovica Ferri · 5 sources
- how a paper about precognition kicked off psychology's replication crisis
In 2011 a respected social psychologist published nine experiments in a top journal suggesting people can sense the future. The methods were completely standard. That was the problem: if standard methods could 'prove' precognition, what else were they proving?
Sara Lindt · 6 sources
- B.F. Skinner tried to make pigeons steer missiles
WWII project: pigeons in the nose cone, trained to peck at an image of the target to steer. It apparently worked in tests and was cancelled anyway. Later he showed pigeons fed at random intervals develop odd ritual behaviors, which he called superstition.
Yuki Tanabe · 6 sources
- I lost an argument about the Monty Hall problem, then lost it again
Switching wins 2/3 of the time. I knew that! I still couldn't explain it at dinner until we played it with three cards about 30 times.
Milan Popović · 6 sources
- the weirdest split or steal ever
One contestant flat-out announces he's going to steal, and promises to share the money after the show. The other guy is furious. Then they open the balls. Better game theory lesson than any lecture I sat through.
Tomás Rinaldi · 5 sources
- experts vs dart-throwing chimps, and the amateurs who beat both
Tetlock tracked tens of thousands of predictions from experts over almost two decades. On average they did little better than chance, and the more famous ones did worse. Then he ran a tournament and found a small group of amateurs who were consistently, measurably good. Mostly they broke questions into parts, started from base rates, and updated in small steps.
Tomás Rinaldi · 6 sources
- why did Homer call the sea wine-dark?
Lin Chen · 6 sources
- why I keep seeing faces in electrical outlets
Started on r/Pareidolia, ended on why the brain has a region that's so into faces. The usual explanation is that a false alarm costs nothing and missing a real face costs a lot, so the detector is tuned to fire easily.
Tess Quinlan · 5 sources
- a 1983 paper called Ironies of Automation describes every problem with AI agents
Short paper, very readable, by Lisanne Bainbridge. The core irony: you automate the easy parts, leave the human to watch, and then expect them to take over in exactly the hardest situations, after they've lost practice and context.
Dev Malhotra · 5 sources
- people will pay $2 for a dollar
Auction off a dollar. The highest bid wins it, but the second-highest bidder pays too. Bidding goes past a dollar almost every time, because at every step quitting looks worse than one more bid.
Milan Popović · 6 sources
- why unfinished things nag at you
Hannah Kim · 5 sources
- the jam study: do more choices really make people buy less?
Lin Chen · 5 sources
- Clever Hans and why ML models cheat
A horse that 'did arithmetic' by reading tiny cues from the questioner's body. ML models do the same thing: a classifier that 'detects pneumonia' by reading the hospital's watermark on the X-ray.
moth · 4 sources
- Semmelweis figured out handwashing and nobody listened
1840s Vienna: one maternity clinic staffed by doctors and medical students, who often came straight from autopsies, had a far higher death rate than the one staffed by midwives. He made them wash in chlorinated lime and deaths dropped dramatically. He was right before germ theory could explain why, he was bad at persuading people, and he died in an asylum in 1865, the same year Lister began antiseptic surgery.
Noor Rahman · 6 sources
- the Stanford Prison Experiment was more performance than experiment
Lin Chen · 5 sources
- why cockpits went from three pilots to two
The flight engineer job got automated away, and CRM came out of crashes where a crew noticed a problem but nobody felt able to tell the captain.
Dev Malhotra · 5 sources
- the crosswalk button probably isn't doing anything
In a lot of big cities the walk signal runs on a fixed timer for much of the day and the button does nothing, at least at those times. The New York Times reported in 2004 that most of NYC's buttons didn't work. Elevator door-close buttons in the US are a similar story in normal operation.
Jonah Feld · 4 sources