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In a 2005 study, people chose which of two faces they found more attractive and were then handed the photo again, but researchers had secretly swapped it for the rejected one using a card trick. Most swaps went unnoticed, and some people explained why they had 'chosen' a face they had actually turned down.

Petter Johansson et al., 2005 study (Science)

MindScience

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Petter Johansson, Lars Hall and colleagues at Lund University in Sweden named this choice blindness. It is one example of what psychologists call the introspection illusion: we feel we can see the reasons for our choices, but our explanations are often built afterwards. The team later took the trick into a supermarket, where shoppers tasted two jams or teas, picked one, and were then given the other from a jar made to look like their choice; most did not notice. In a 2012 study they used a rigged clipboard to reverse people's answers on moral questions, and many went on to argue for views they had just rejected.

Türkçe oku
2005'teki bir araştırmada katılımcılar iki yüzden hangisini daha çekici bulduklarını seçti, ardından fotoğraf ellerine yeniden verildi. Oysa araştırmacılar bir el çabukluğuyla fotoğrafı reddedilen yüzle değiştirmişti. Değişikliklerin çoğu fark edilmedi; bazı katılımcılar, aslında beğenmedikleri yüzü neden “seçtiklerini” bile anlattı.

İsveç'teki Lund Üniversitesi'nden Petter Johansson, Lars Hall ve arkadaşları bu olguya “seçim körlüğü” adını verdi. Psikologların “iç gözlem yanılsaması” dediği şeyin bir örneğidir: seçimlerimizin nedenlerini gördüğümüzü sanırız, ama açıklamalarımızı çoğu zaman sonradan kurarız. Ekip bu numarayı daha sonra bir süpermarkete taşıdı: alışveriş yapanlar iki reçel ya da iki çay tadıp birini seçti, ardından seçtikleri kavanoz gibi görünen bir kavanozdan ötekini tattı; çoğu farkına varmadı. 2012'deki bir çalışmada ise hileli bir not panosuyla katılımcıların ahlaki sorulara verdiği yanıtlar tersine çevrildi ve birçoğu az önce reddettiği görüşleri savunmaya koyuldu.

Sources and further reading

Background reading: Choice blindness
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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.

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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.

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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.

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