Ikigai Daily
Menu
WonderFact

The morning after the space shuttle Challenger exploded in 1986, the psychologists Ulric Neisser and Nicole Harsch asked students to write down how they had heard the news. Years later, many vivid memories no longer matched: one student was sure she had seen it on TV with her roommate, but her note said she had heard it in class.

Ulric Neisser & Nicole Harsch, 1992

MindScience

The story behind the card

The psychologists Roger Brown and James Kulik coined the term “flashbulb memory” in 1977 for the vivid, confident memories people form around shocking news, and suggested such memories are unusually accurate. Neisser and Harsch put this to the test. More than two years after the disaster, they asked the same students again how they had heard. Many accounts had changed on basic details such as where they were and who told them, about a quarter were wrong on every main point, and yet most students felt sure of their memories. Some, shown their own handwritten notes, still trusted the later version. Studies after the attacks of 11 September 2001 found the same pattern: confidence stays high while accuracy fades.

Türkçe oku
Challenger uzay mekiği 1986'da patladığında, psikologlar Ulric Neisser ve Nicole Harsch ertesi sabah öğrencilerden haberi nasıl duyduklarını yazmalarını istedi. Yıllar sonra birçok canlı anı bu notlarla uyuşmuyordu: bir öğrenci haberi oda arkadaşıyla televizyonda gördüğünden emindi, oysa notunda derste duyduğunu yazmıştı.

Psikologlar Roger Brown ve James Kulik, 1977'de sarsıcı haberler karşısında oluşan canlı ve güvenle hatırlanan anılara “flaş bellek” adını verdi ve bu anıların alışılmadık ölçüde doğru olduğunu öne sürdü. Neisser ve Harsch bu iddiayı sınadı. Felaketten iki yılı aşkın süre sonra aynı öğrencilere haberi nasıl duyduklarını yeniden sordular. Birçok anlatımda nerede oldukları ya da haberi kimden duydukları gibi temel ayrıntılar değişmişti; yaklaşık dörtte biri ana noktaların hepsinde yanılıyordu. Yine de öğrencilerin çoğu anılarından emindi. Bazıları kendi el yazılarıyla tuttukları notları görünce bile sonraki anlatıma inanmayı sürdürdü. 11 Eylül 2001 saldırılarından sonra yapılan çalışmalar da aynı tabloyu gösterdi: Anıya duyulan güven yüksek kalıyor, doğruluk ise azalıyor.

Sources and further reading

Background reading: Flashbulb memory
Get the mobile appAbout our cards

Related cards

These cards share a subject or reading mode with the card above.

WonderScience

Deliberately smiling can make people feel slightly happier. In 2022 a study of nearly 4,000 people in 19 countries found that posing a smile, or copying a smiling face, raised reported happiness a little; a subtler method, holding a pen between the teeth, gave less clear results.

The idea that the face can feed back into feelings, called the facial feedback hypothesis, goes back to Charles Darwin and William James. In a famous 1988 experiment, Fritz Strack and colleagues had people hold a pen in their teeth, which forces a smile, or between their lips, which prevents one, and those in the first group rated cartoons as funnier. In 2016, seventeen laboratories repeated that experiment exactly and found no effect. A 2019 review of 138 studies concluded that the effect is real but small and varies from study to study. The 2022 Many Smiles Collaboration, led by Nicholas Coles and designed jointly by supporters and sceptics of the idea, found that deliberate smiling could both strengthen and start feelings of happiness, while the pen method remained inconclusive.

Ikigai DailyRead card
WonderScience

Your gut and brain communicate through nerves, hormones, immune signals and microbes, which is why stress and digestion can affect each other.

Scientists call this link the gut–brain axis. The gut has its own network of about 500 million nerve cells, the enteric nervous system, sometimes called the “second brain”, which can run digestion largely by itself. It is connected to the brain mainly through the vagus nerve, a long nerve running from the brainstem down to the abdomen, and most of its fibres carry messages upwards, from the gut to the brain. More than 90 per cent of the body's serotonin, a chemical messenger, is found in the gut. Gut bacteria play a part too: in a 2004 Japanese study, mice raised entirely free of germs overreacted to stress. Stress can speed up or slow down the gut, one reason it often worsens irritable bowel syndrome, a common gut disorder. Most research on the microbes' role has been in animals, and human evidence is still limited.

Ikigai DailyRead card
WonderScience

A placebo is a dummy treatment, such as a sugar pill. In pain studies, placebos can reduce the pain people report and also dampen activity in the brain areas that process pain, even though they contain no active drug.

The word placebo is Latin for “I shall please”. One of the first clues that the effect is physical came in 1978, when Jon Levine and colleagues studied patients recovering from wisdom tooth removal. They gave them a placebo and naloxone, a drug that blocks the effect of endorphins, the body's own painkilling chemicals. In patients who had responded to the placebo, naloxone increased the pain, which suggested that the placebo relief came from endorphins. In 2004 Tor Wager and colleagues used brain scans to show that a placebo painkiller reduced activity in pain-processing regions during a painful stimulus. Expectation works the other way too: in the nocebo effect, from the Latin for “I shall harm”, expecting harm makes symptoms worse. None of this means the pain was imaginary, or that placebos can replace effective treatment.

Ikigai DailyRead card
WonderScience

Memory does not work like a recording. Each time we recall an event, the brain rebuilds it from stored fragments, filling gaps with what we know and what we have heard since, so a memory can change without our noticing.

Psychologists call this reconstructive memory. In his 1932 book Remembering, the British psychologist Frederic Bartlett described asking people to retell “The War of the Ghosts”, a Native American folk tale unfamiliar to them; each retelling drifted towards what felt familiar in their own culture. In 1974 Elizabeth Loftus and John Palmer showed people films of car accidents and asked how fast the cars were going when they “hit” or “smashed” into each other. Those asked with “smashed” gave higher speeds, and a week later were more likely to remember broken glass that was never there. This is known as the misinformation effect. It matters in court: according to the Innocence Project, mistaken eyewitness identification played a part in most US convictions later overturned by DNA evidence.

Ikigai DailyRead card
WonderScience

Predictive processing, an influential theory in neuroscience, says the brain does not simply wait for information from the senses. It keeps guessing what is out there and uses the incoming signals mainly to check and correct those guesses.

The idea goes back to the German physicist Hermann von Helmholtz, who argued in the 1860s that seeing involves “unconscious inference”: the brain fills in what the eyes cannot fully tell it. In 1999 the researchers Rajesh Rao and Dana Ballard turned this into a computer model of vision. Higher brain areas send predictions down, and lower areas send back only the difference between prediction and input, called the prediction error. The philosopher Andy Clark and the neuroscientist Karl Friston later helped develop it into a broad theory of the mind. A well-known illustration is the hollow-mask illusion: the inside of a mask still looks like a face bulging outwards, because the brain's expectation of a normal face outweighs the evidence. The theory is widely used but still debated, and critics ask how some of its claims could be tested.

Ikigai DailyRead card
Next card in the archiveIn a 1973 field experiment, preschoolers who already liked drawing were split into three groups: some were promised a reward for drawing, some got the same reward as a surprise afterwards, and some got none. Given free time later, the children who had expected the reward chose to draw less than the other two groups.Read next →