Facts about psychology
Psychology facts describe the shortcuts your mind takes without asking permission. We misjudge randomness, remember interrupted tasks better than finished ones, and change our answers when a group disagrees with us. The entries here stick to findings that have held up under replication, avoid the pop-science versions that overstate them, and explain what the effect really predicts about everyday behaviour.
People who know the least about a subject often feel the most confident about it.
In 1999, psychologists David Dunning and Justin Kruger found that the lowest-scoring participants in tests of logic, grammar and humour rated their own performance far above average. Top performers, meanwhile, tended to underestimate themselves.
Placebos can relieve symptoms even when patients are told they are taking a placebo.
In several trials, people with conditions such as irritable bowel syndrome or chronic back pain improved after taking pills clearly labelled as placebos. They knew there was no active drug.
Walking through a doorway really can make you forget why you came into the room.
In experiments, people who carried objects between rooms in a virtual or real building were worse at remembering what they held than people who walked the same distance within one room. Psychologists call it the doorway effect.
You remember unfinished tasks better than finished ones.
In the 1920s, psychologist Bluma Zeigarnik noticed that waiters could recall unpaid orders in detail but forgot them as soon as the bill was settled. Her experiments showed people remember interrupted tasks far better than completed ones.
We tend to like things simply because we have seen them before.
Psychologist Robert Zajonc showed people nonsense words, shapes and faces, and found that the more often something was shown, the more they liked it. This is the mere-exposure effect, and it works even when people do not consciously remember seeing the item.
Half the people in a famous experiment did not notice that the stranger they were talking to had been swapped for someone else.
In 1998, a researcher asked passers-by for directions. Halfway through, two men carrying a door walked between them, and a different researcher took over the conversation. About half of the people carried on as if nothing had happened.
People notice your embarrassing moments far less than you think.
In a 2000 study, students had to walk into a room wearing a T-shirt with a large picture of Barry Manilow. They guessed that about half the people present would notice; in reality, fewer than a quarter did.
Adding a third option that nobody wants can change what people buy.
Offer a small popcorn for 3 and a large for 7, and most people pick the small. Add a medium for 6.50 and suddenly the large looks like a bargain, so many more people choose it. The medium exists only to be rejected.
A year after a big win, lottery winners are about as happy as they were before.
A 1978 study compared lottery winners, people paralysed in accidents and a control group. The winners were only slightly happier than the controls, and took less pleasure in everyday things like breakfast or a chat with a friend.
In 2015, a photo of a dress split the internet because people literally saw different colours.
Some viewers saw the dress as white and gold, others as blue and black. It was in fact blue and black. Millions argued about it, and vision scientists published studies on why.
The more people who witness an emergency, the less likely any one of them is to help.
In experiments from the 1960s onward, people who believed they were the only witness to someone in trouble helped quickly. When they believed others could also hear, most waited, assuming someone else would act.