Professional swimmers don't have perfect bodies because they train extensively. Rather, they are good swimmers because of their physiques. How their bodies are designed is a factor of selection an not the result of their activities. Similarly, female models advertise cosmetics and thus, many female consumers believe that these products make you beautiful. But it is not the cosmetics that make those women model-like. Quite simply, the models are born attractive and only for this reason are they candidates for cosmetic advertising.

(s. 8)

Harvard has the reputation of being a top university. Many highly successful people have studied there. Does this mean that Harvard is a good school? We don't know. Perhaps the school is terrible, and it simply recruits the brightest students around.

(s. 9)

When I ask happy people about the secret of their contentment, I often hear answers like 'You have to see the glass half-full rather than half-empty.' It is as if these individual do not realise that they were born happy, and now tend to see the positive in everything. They do not realise that cheerfulness - according to many studies, such as those conducted by Harvard's Dan Gilbert - is largely a personality trait that remains constant throughout life. Or, as social scientists Lykken and Tellegen starkly suggest, 'trying to be happier is as futile as trying to be taller.' Thus, the swimmer's body illusion is also a self-illusion. When these optimists write self-help books, the illusion can become treacherous. […] For billions of people, these pieces of advice are unlikely to help. But because the unhappy don't write self-help books about their failures, this fact remains hidden.

(s. 9-10)

Social proof, sometimes roughly termed the herd instinct, dictates that individuals feel they are behaving correctly when they act the same as other people.

(s. 14)

A simple experiment carried out in the 1950s by legendary psychologist Salomon Asch show show peer pressure can warp common sens. A subject is shown a line drawn on paper, and next to it three lines - numbered 1, 2 and 3 - one shorter, one longer and one of the same length as the original one. He or she must indicate which of three lines corresponds to the original one. If the person is alone in the room, he gives correct answers - unsurprising, because the task is really quite simple. Now five other people enter the room; they are all actors, which the subject does not know. One after another, they give wrong answers, saying 'number 1'. Then it is the subject's turn again. In one third of cases, he will answer incorrectly to match the other people's responses.

(s. 15)

Not so long ago, you may have come across disciples of the Hare Krishna sect floating around in saffron-coloured robes as you hurried to catch a flight or a train to your destination. A member of the sect presented you with a small flower and a smile. If you're like most people, you took the flower, if only not to be rude. If you tried to refuse, you would have heard a gentle 'Take it, this is our gift to you.' If you wanted to dispose of the flower in the next trashcan, you found that there were already a few there. But that was not the end. Just as your bad conscience started to tug at you, another disciple of Krishna approached you, this time asking for a donation. In many cases, this plea was successful - and so pervasive that many airports banned the sect from the premises.

Many NGOs and philanthropic organisations use exactly the same techniques: first give, then take.

(s. 20)

Over the past decade, airlines have also learned the dangers of the authority bias. In the old days, the captain was king. His commands were not to be doubted. If a co-pilot suspected an oversight, he wouldn't have dared to address it out of respect for - or fear of - his captain. Since this behaviour was discovered, nearly every airline has instituted 'Crew Resource Management,' which coaches pilots and their crews to discuss any reservations they have openly and quickly. In other words: they carefully deprogramme the authority bias.

Authorities crave recognition and constantly find ways to reinforce their status. Doctors and researchers sport white coats. Bank directors don suits and ties. Kings wear crowns. Members of the military wield rank badges. Today even more symbols and props are used to signal expertise: from appearances on talk shows and on the covers of magazines, to book tours and their own Wikipedia entries.

(s. 30)

American researcher has been investigating acoustic sensitivity to pain. For this, he placed people in sound booths and increased the volume until the subjects signaled him to stop. The two rooms, A and B, were identical, save one thing: room B had a red panic button on the wall. The button was purely for show, but it gave participants the feeling that they were in control of the situation, leading them to withstand significantly more noise. If you have read Aleksandr Solzhenitsyn, Primo Levi or Viktor Frankl, this finding will not surprise you: the idea that people can influence their destiny even by a fraction encouraged these prisoners not to give up hope.

Crossing the street in Los Angeles is a tricky business, but luckily, at the press of a button, we can stop traffic. Or can we? The button's real purpose is to make us believe we have an influence on the traffic lights, and thus we're better able to endure the wait for the signal to change with more patience. The same goes for 'door-open' and 'door-close' buttons in elevators: many are not even connected to the electrical panel. Such tricks are also designed into openplan offices: for some people it will always be too hot, for others too cold. Clever technicians create the illusion of control by installing fake temperature dials.

(s. 55)

Large selection leads to discontent. How can you be sure you are making the right choice when 200 options surround and confound you? The answer is: you cannot. The more choice you have, the more unsure and therefore dissatisfied you are afterwards.

So, what can you do? Think carefully about what you want before you inspect existing offers. Write down these criteria and stick to them rigidly. Also, realise that you can never make a perfect decision. Aiming for this, given the flood of possibilities, is a form of irrational perfectionism. Instead, learn to love a 'good' choice. Yes, even in terms of life partners. Only the best will do? In this age of unlimited variety, rather the opposite is true: 'good enough' is the new optimum.

(s. 68)

Joe Girard is considered the most successful car salesman in the world. His tip for success: 'There's nothing more effective in selling anything than getting the customer to believe, really believe, that you like him and care about him.' Gerard doesn't just talk the talk: his secret weapon is sending a card to his customers each month. Just one sentence salutes them: 'I like you.'

The liking bias is startingly simple to understand and yet we continually fall prey to it. It means this: the more we like someone, the more inclined we are to buy from or help that person. Still, the question remains: what does 'likeable' even mean? According to research, we see people as pleasant if A) they are outwardly attractive, B) they are similar to us in terms of origin, personality or interests, and C) they like us.

Miroring is a standard technique in sales to get exactly this effect. Here, the salesperson tries to copy the gestures, language, and facial expressions of his prospective client. If the buyer speaks very slowly and quietly, often scratching his head, it makes more sens for the seller to speak slowly and quietly, and to scratch his head now and then too. That makes him likeable in the eyes of the buyer, and thus a business deal is more likely. Finally, it's not unheard of for advertisers to pay us compliments: how many times have you bought something 'because you're worth it'?

(s. 69-70)