πŸ’Ž Bayesian thinking and the importance of applying a base rate when interpreting new data

The core of Bayesian thinking (or Bayesian updating, as it can be called) is this: given that we have limited but useful information about the world, and are constantly encountering new information, we should probably take into account what we already know when we learn something new. As much of it as possible. Bayesian thinking allows us to use all relevant prior information in making decisions. Statisticians might call it a base rate, taking in outside information about past situations like the one you’re in.

Consider the headline β€œViolent Stabbings on the Rise.” Without Bayesian thinking, you might become genuinely afraid because your chances of being a victim of assault or murder is higher than it was a few months ago. But a Bayesian approach will have you putting this information into the context of what you already know about violent crime. You know that violent crime has been declining to its lowest rates in decades. Your city is safer now than it has been since this measurement started. Let’s say your chance of being a victim of a stabbing last year was one in 10,000, or 0.01%. The article states, with accuracy, that violent crime has doubled. It is now two in 10,000, or 0.02%. Is that worth being terribly worried about? The prior information here is key. When we factor it in, we realize that our safety has not really been compromised.

Excerpt from: The Great Mental Models Volume 1: General Thinking Concepts by Shane Parrish and Rhiannon Beaubien

πŸ’Ž On copywriting (briefly)

So, gather your facts and get under the skin of your target. Talk to them in their language, not the Queen’s. What else? Be brief. I believe it was Pascal who added an apology to the bottom of a long letter, explaining that he hadn’t had time to write a short one. Why take twenty words to say what you could say in five? Why decide on a long copy ad when a poster-in-the-press will do? For most people, and particularly women who work outside as well as inside the home, money isn’t the most precious commodity these days; time is. We copywriters would do well to respect that.

Excerpt from: D&Ad Copy Book by D&AD

 

πŸ’Ž On how the serial-position effect (we remember beginnings and ends best) can improve your presentations

Accept that many things in the middle of your presentation may be lost. If the middle is more than 20 minutes long, break it up with activities and exercises. By doing this you are essentially creating several small presentations within your presentation. That means each of these small presentations also has a beginning, middle, and end. Since people tend to remember beginnings and endings,

Try breaking up a presentation into several small β€œpresentations” means that people will have a lot more beginnings and endings than middiesβ€”they will remember more information.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž On how we can be trapped by our own perspective

The first flaw is perspective. We have a hard time seeing any system that we are in. Galileo’ had a great analogy to describe the limits of our default perspective. Imagine you are on a ship that has reached constant velocity (meaning without a change in speed or direction). You are below decks and there are no portholes. You drop a ball from your raised hand to the floor. To you, it looks as if the ball is dropping straight down, thereby confirming gravity is at work.

Now imagine you are a fish (with special x-ray vision) and you are watching this ship go past. You see the scientist inside, dropping a ball. You register the vertical change in the position of the ball. But you are also able to see a horizontal change. As the ball was pulled down by gravity it also shifted its position east by about 20 feet. The ship moved through the water and therefore so did the ball. The scientist on board, with no external point of reference, was not able to perceive this horizontal shift.

This analogy shows us the limits of our perception. We must be open to other perspectives if we truly want to understand the results of our actions. Despite feeling that we’ve got all the information, if we’re on the ship, the fish in the ocean has more he can share.

Excerpt from: The Great Mental Models Volume 1: General Thinking Concepts by Shane Parrish and Rhiannon Beaubien

πŸ’Ž On the seemingly elusive aspect of money

At a party given by a billionaire on Shelter Island, Kurt Vonnegut informs his pal, Joseph Heller, that their host, a hedge fund manager, had made more money in a single day than Heller had earned from his wildly popular novel Catch-22 over its whole history. Heller responds, β€œYes, but I have something he will never have … enough.”

Enough. I was stunned by the simple eloquence of that wordβ€”stunned for two reasons: first, because I have been given so much in my own life and, second, because Joseph Heller couldn’t have been more accurate.

For a critical element of our society, including many of the wealthiest and most powerful among us, there seems to be no limit today on what enough entails.For a critical element of our society, including many of the wealthiest and most powerful among us, there seems to be no limit today on what enough entails.

Excerpt from: The Psychology of Money: Timeless lessons on wealth, greed, and happiness by Morgan Housel

πŸ’Ž Why conflicts can escalate quickly despite the illusion of proportionately

A team of psychologists at University College London invited subjects into the lab in pairs. The first person was hooked up to a little squeezing machine, which applied a very small force on her finger. She was then instructed to press down on the other person’s finger using exactly the same amount of force. Crucially, the other person had no idea about this part of the instruction.

β€˜The second person was then instructed to push back on the first person’s finger, using exactly the same amount of force as they felt. The two individuals traded finger pushes, while the scientists measured the precise force they used. In every pair of pushers tested, the use of force escalated quickly, until the two people were pushing down on each other’s finger with about twenty times the original force.

It’s an experiment that offers an ominous glimpse into the dynamics of human escalation. Each participant thought they were behaving proportionately to the other, and while nobody was deliberately raising the stakes, somehow the pressure rose anyway.

Excerpt from: Conflicted: Why Arguments Are Tearing Us Apart and How They Can Bring Us Together by Ian Leslie

πŸ’Ž The power of using nouns (being a voter) over verbs (voting)

You can stimulate group identity just by the way you have people talk about themselves or the way you phrase a question. For example, Gregory Walton’s research shows that if people say β€œI am a chocolate eater” versus β€œI eat chocolate a lot,” it affects the strength of their preference for chocolate. β€œEater” is a noun. β€œEat” is a verb. People who say β€œI am a chocolate eater,” who use the noun instead of the verb, show a stronger preference for chocolate.

In a survey about voting, Walton’s experimenters asked, β€œHow important is it to you to be a voter in tomorrow’s election?” versus β€œHow important is it to you to vote in tomorrow’s election?” When the noun (voter) was used instead of the verb (vote), more people actually voted the following day. Feeling that you belong to a specific group affects your behavior.

When you ask people to do stuff, use nouns rather than verbs. Invoke a sense of belonging to a group and people are much more likely to comply with your request.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž A simple but creative nudge that helped reduce workplace accidents (gold coin decals)

Globally, there are an estimated 340 million workplace accidents each year. These accidents are enormously damaging to both individuals’ lives and their contribution to the economy. While some accidents are a result of poor working conditions, others stem from the behavior of workers. For example, employees in a Chinese textile factory were in the habit of throwing waste scraps of cloth on the floor next to them, creating a slipping hazard. An explanation of why this habit had formed was that workers were financially motivated to continue working without breaks. Initially, the factory tried a traditional approach to influence behavior: offering monetary incentives to workers if they put waste in trash cans. The effect was disappointing: scraps were still thrown on the floor, and the danger remained.

Sherry Jueyu Wu and Betsy Levy Paluck, researchers partnering with the factory, thought that meaningful visual cues on the floor might help change behavior. Specifically, they introduced decals depicting golden coins on the production floors. Culturally, golden coins are considered to symbolize fortune and luck, meaning the employees would have a disincentive to cover them with waste. Introducing these decals led to a 20 percent decline in waste on the floor. A small, contextually meaningful change to the design of the environment was enough to overcome a seemingly entrenched habit.

Excerpt from: Behavioural Insights by Michael Hallsworth

πŸ’Ž Advertisers would do better to fear indifference than alienating consumers (real people don’t much care)

  • When it comes to ads, though, remember that real people don’t much care about them. So negative effects are rare.
  • We know of no evidence of any advertising that has had a negative effect on sales.
  • Don’t worry about ‘alienation’. Negative effects among existing buyers but not new buyers or vice versa won’t happen; we can’t think of any examples.
  • So don’t hold back from bold, provocative ideas through fear of alienation. You should be much more fearful of indifference – and that’s wonderfully liberating creatively.

Excerpt from:Β How not to Plan: 66 ways to screw it up by Les Binet and Sarah Carter

πŸ’Ž The fallibility of memory (even for big events)

Although flashbulb memories are vivid, they are also full of errors. In 1986 the space shuttle Challenger exploded. If you to recall that event, you probably remember it vividly. The day after this tragic event, Ulric Neisser, a professor who researches memories like these, he had his students write down their memories of what had happened. Three years later he asked them to write their memory of the event again (Neisser. 1992). Over 90 percent of the later reports differed from the originals. Half of them were inaccurate in two-thirds of the details. One person, when shown the description she had written three years earlier, said, β€œI know that’s my handwriting, but I couldn’t possibly have written that.” Similar research has been conducted on individuals with memories of the 9/11 attacks, with similar results.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž Beware claimed data (people don’t like to admit they ‘don’t know’ when questioned)

However, serious academic consideration of public opinion about fictitious issues did not start until the ’80s, when George Bishop and colleagues at the University of Cincinnati found that a third of Americans either favoured or opposed the fictitious Public Affairs Act. Bishop found that this figure dropped substantially when respondents were offered an explicit don’t know’ option. However, 10 per cent of respondents still selected a substantive answer, even when given a clear opportunity to express their lack of familiarity. Similar findings were reported in the US at around the same time by Howard Schuman and Stanley Presser, who also found that a third of respondents to their survey expressed positions on issues which, though real, were so obscure that few ordinary citizens would ever have heard of them.

Excerpt from: Sex, Lies and Politics: The Secret Influences That Drive our Political Choices by Philip Cowley and Robert Ford

πŸ’Ž Beware interpreting stats on anything you have a strongly held view about (from politics to Covid and beyond)

It’s much more challenging when emotional reactions are involved, as we’ve seen with smokers and cancer statistics. Psychologist Ziva Kunda found the same effect in the lab when she showed experimental subjects an article laying out the evidence that coffee or other sources of caffeine could increase the risk to women of developing breast cysts. Most people found the article pretty convincing. Women who drank a lot of coffee did not.

We often find ways to dismiss evidence that we don’t like. And the opposite is true, too: when evidence seems to support our preconceptions, we are less likely to look too closely for flaws.

The more extreme the emotional reaction, the harder it is to think straight.

Excerpt from: How to Make the World Add Up: Ten Rules for Thinking Differently About Numbers by Tim Harford

πŸ’Ž Beware the Rosser Reeves effect when interpreting tracking data (communication effectiveness)

Research routinely shows that people who’re aware of communication from brand X are more likely to buy that brand. Sometimes used as evidence that communication drives sales, in fact causality usually runs the other way: buying brand X makes you more likely to notice its communications. This phenomenon (the so-called ‘Rosser Reeves effecΕ₯ – named after the famous 1950s adman) has been known for decades, yet is still routinely used to ‘prove’ communication effectiveness (most recently to justify social media use).

Excerpt from:Β How not to Plan: 66 ways to screw it up by Les Binet and Sarah Carter

πŸ’Ž On the discrepancy between how important music is in ads and how little attention it gets from marketers (less than 0.1%)

Our disregard for the importance of music shows when we look at research literature. Of over 48,000 articles on the WARC database, only 10% of them mention music at all. Only 29 (less than 0.1%) discuss it in any detail. But the research that has been done on the effects of music suggests these are far greater than we seem to assume.

Research shows that music increases the attention paid to ads as well as recall of brand and message. We suspect these effects may be very long term. Think about the ads we remember word for word from childhood – it’s highly likely they used music.

It’s striking how often music is central to these famous campaigns. It’s estimated that the free media exposure arising from the music in John Lewis’s Christmas ad each year increases campaign impact by around 75%.

Given all this, it’s perhaps not surprising that the IPA Databank shows that TV ads using music prominently are significantly more effective than ads that don’t, enhancing effectiveness by 20-30%.

So, over a fifth of the effect of an ad may come from its music – meaning choice of music can easily determine whether or not the ad pays for itself.

That’s too important to leave to the last minute.

Excerpt from:Β How not to Plan: 66 ways to screw it up by Les Binet and Sarah Carter

πŸ’Ž On the tendency of marketers to exaggerate the amount consumers change (social trends)

Marketing and advertising people can talk a load of nonsense at the best of times. But if you want to hear them at their worst, ask them to talk about social trends. The average social trends presentation is a guaranteed mix of the obvious, irrelevant and false.

Recently, we were listening to a conference speech about changing lifestyles’. Life nowadays is faster than ever, said the speaker. We work longer hours. We have less free time. Families are fragmenting. Food is eaten on the run..

We’ve been listening to this bullshit for 30 years. And it’s no more true now that it was then. The inconvenient, less headline-worthy truth is that people have more free time than ever. Economic cycles wax and wane, but the long-term trend in all developed economies is toward shorter, more flexible working hours. And longer holidays. People start work later in life and spend much longer in retirement. Work takes up a smaller percentage of our life than it used to.

Related myths about pressures on. family time are equally false. Contrary to popular belief, in developed economies parents spend more time with their children these days. Not less. Research shows the amount of time families spend eating together has stayed remarkably constant over the years, As has the amount of time they spend together watching TV.

Excerpt from:Β How not to Plan: 66 ways to screw it up by Les Binet and Sarah Carter

πŸ’Ž Titles and headlines are critical (frame the message)

Read this paragraph:

First you sort the items into like categories. Using color for sorting is common, but you can also use other characteristics, such as texture or type of handling needed.. Once you have sorted the items, you are ready to use the equipment. You want to process each category from sorting separately. Place one category in the at a time

What is the paragraph about? It’s hard to understand. But what if I give you the same paragraph with a title:

Using your new washing machine

First you sort the items into like categories. Using color for sorting is common, but you can also use other characteristics, such as texture or type of handling needed. Once you have sorted the items, you are ready to use the equipment. You want to process each category from the sorting separately. Place one category in the machine at a time.

The paragraph is still poorly written, but now at least it is understandable.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž On the benefits of brevity (sell your idea or your dream in 10 to 15 minutes)

Let’s put this in perspective. Abraham Lincoln inspired generations in a speech that lasted two minutes. John F. Kennedy took 15 minutes to shoot for the moon. Martin Luther King Jr. articulated his dream of racial unity in 17 minutes. Steve Jobs gave one of the most famous college commencement speeches of our time at Stanford University in 15 minutes. If you can’t sell your idea or your dream in 10 to 15 minutes, keep editing until you can.

Ideas don’t sell themselves. Be selective about the words you use. If they don’t advance the story, remove them. Condense, simplify, and speak as briefly as possible. Have the courage to speak in grade-school language. Far from weakening your argument, these tips will elevate your ideas, making it more likely you’ll be heard.

Excerpt from: Five Stars: The Communication Secrets to Get From Good to Great by Carmine Gallo

πŸ’Ž All speeches have three versions (before, during, ideal)

“There are always three speeches for every one you actually gave: the one you practiced, the one you gave, and the one you wish you gave.”

-Dale Carnegie

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž Diane Dors on why she ‘rebranded’ (Diana Fluck)

Among the film’s cast were three people who would all go on to become famous – in one case, notorious. The first was born Diana Fluck in Swindon; she had changed her name because, as she later said, ‘what would happen if they put my name up in lights … and one of the bulbs burst?’ She had chosen the name Diana Dors, and very soon was being touted as Britain’s answer to Marilyn Monroe and Jayne Mansfield.

Excerpt from: Elizabethans: How Modern Britain was Formed by Andrew Marr

πŸ’Ž Abundance is the enemy of appreciation (on the benefits of abstinence)

But there’s a way to maximize the pleasure of that second confection. Temporarily giving up chocolate can restore our ability to enjoy it. After an initial chocolate tasting, students promised to abstain from chocolate for one week. Another group of students pledged to eat as much chocolate as they comfortably could, and they received a two-pound bag of chocolate to help them fulfill their pledge. The students who left with this reservoir of chocolatey goodness may seem like the lucky ones. But their sweet windfall came at a price. When they returned the following week to sample additional chocolate, they enjoyed it much less than they had the week before. People only enjoyed chocolate as much the second week as they had the first if they had given it up in between.”

Except from:Β Happy Money: The New Science of Smarter Spending by Elizabeth Dunn and Michael Norton

πŸ’Ž Experiences are less likely to suffer from the problem of unflattering comparisons than possessions (we like to compare ‘things’)

The apples-and-oranges quality of experiences also makes it easier to enjoy them in the moment, unfettered by depressing comparisons. Researchers at Cornell gave students a Pilot G2 Super Fine pen as a prize and asked them to try it out. When it was surrounded by inferior prizes, including an unsharpened pencil and a bag of rubber bands, the students gave the pen rave reviews. Other students saw the same pen alongside a USB drive and a leatherbound notebook. The presence of more desirable goods significantly diminished the pen’s appeal. This simple study illustrates one of the major barriers to increasing human well-being. We are happy with things, until we find out there are better things available.

Luckily, this tendency may be limited to things. Even the simplest experiences, like eating a bag of crisps, are relatively immune to the detrimental effects of attractive alternatives. Offered the chance to eat a bag of crisps, students enjoyed the crisps’ crunchy goodness regardless of whether the surrounding alternatives included Cadbury’s chocolate or clam juice.

Except from:Β Happy Money: The New Science of Smarter Spending by Elizabeth Dunn and Michael Norton

πŸ’Ž On how anchors influence us (even when they bear no relationship to the estimated value)

Surprisingly, anchors influence us even when they bear no relationship to the estimated value, and even when they’re patently absurd. Following the seminal experiments of Kahneman and Tversky in the 1970s, two German researchers named Thomas Mussweiler and Fritz Strack demonstrated this effect with remarkable creativity. In one of their experiments, they divided their subjects into two groups, asking one group whether Mahatma Gandhi was over or under 140 years old when he died, and the other whether he was over or under 9 years old when he died. Obviously, no one had trouble answering these questions. But when the respondents were then asked to estimate Gandhi’s age at death, these clearly ridiculous β€œanchors” made a difference: the group anchored on 140 thought, on average, that Gandhi had died at age 67, whereas the group anchored on 9 believed he had died at age 50. (Actually, Gandhi died at age 78.)

Excerpt from: You’re About to Make a Terrible Mistake!: How Biases Distort Decision-Making and What You Can Do to Fight Them by Olivier Sibony

πŸ’Ž How the tiniest of nudges can affect honesty (email versus pen)

NINETY-TWO PERCENT OF GRADUATE STUDENTS LIED

Charles Naquin (2010) from DePaul University and his colleagues have conducted research on honesty in people when using email versus pen and paper.

In one study, forty-eight graduate business students were each given $89 (imaginary money) to divide with their partner; they had to decide whether to tell their partner how much money was in the kitty, as well as how much of the money to share with their partner. One group communicated by email and the other group by a handwritten note. The group that wrote emails lied about the amount of money (92 percent) more than the group that was writing by hand (63 percent). The e-mail group was also less fair about sharing the money, and felt justified in not being honest or fair.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk

πŸ’Ž Trump has one negotiating tactic (anchoring – begin with an absurd ask)

MY STYLE of deal-making is quite simple and straightforward. I aim very high, and then I just keep pushing and pushing and pushing to get what I’m after. Sometimes I settle for less than I sought, but in most cases I still end up with what I want.

Excerpt from: Trump: The Art of the Deal by Donald Trump and Tony Schwartz

πŸ’Ž On the similarities between comedy and advertising (in particular on leaving enough space for the audience to be involved in the interpretation)

So all humour, however broad and however universally understood, is implicit rather than explicit: an explicit joke is either not explicit or not a joke.

All good comedians, all good storytellers, all good makers of advertisements, entice their receivers into willing and constructive collaboration It’s a skilful, delicate and difficult thing to do – particularly in advertising where the pressures of committees and cost tend to favour the ‘explicit, the β€˜unambiguous’, the β€˜message that just can’t fail to be understood.

But the measure of a good joke is much the same as the measure of a good advertisement (judging it now purely in terms of its communications effectiveness). Has it asked enough, but not too much, of its selected audience? Has it allowed that audience to see something for itself? (Whether, in the case of the advertisement, what the audience comes to see is the most persuasive and relevant thing is clearly another question.) So the principles of humour and the principles of commercial persuasion are very close.

Excerpt from:Β Behind the Scenes in Advertising, Mark III: More Bull More by Jeremy Bullmore

πŸ’Ž We are more likely to remember concepts if they are presented to us as pictures rather than words (the picture superiority effect)

A PICTURE SPEAKS A THOUSAND WORDS

We are more likely to remember concepts if they are presented to us as pictures rather than words.

For example, one study of discharged emergency room patients provided half of the participants with text-only instructions to properly care for their wounds, whilst the other half were given both text and cartoon depictions of each step. Three days later, 46% of patients given illustrated instructions demonstrated perfect recall of the prescribed techniques, compared to just 6% in the text-only condition.

UNSEEN OPPORTUNITY

By adding pictures and visual context into your goals, meetings, or even briefs, you can help others digest and retain

Excerpt from: The Unseen Mind by Ogilvy UK

πŸ’Ž On our minds working on problems even when we’re not consciously thinking about them (John Cleese)

Graham and I thought it was rather a good sketch. It was therefore terribly embarrassing when I found I’d lost it. I knew Graham was going to be cross, so when I’d given up looking for it, I sat down and rewrote the whole thing from memory. It actually turned out to be easier than I’d expected.

Then I found the original sketch and, out of curiosity, checked to see how well I’d recalled it when rewriting. Weirdly, I discovered that the remembered version was actually an improvement on the one that Graham and I had written. This puzzled the hell out of me.

Again I was forced to the conclusion that my mind must have continued to think about the sketch after Graham and I had finished it. And that my mind had been improving what we’d written, without my making any conscious attempt to do so. So when I remembered it, it was already better.

Chewing this over, I realised it was like the tip-of-the-tongue phenomenon: when you can’t remember a name, and you chase after it in your mind

Excerpt from: Creativity: A Short and Cheerful Guide by John Cleese

πŸ’Ž The importance of leaving room for the audience to participate whether it’s a screenplay or an ad (arriving late and leaving early)

Goldman has never written a commercial in his life yet you’ll learn more from his storytelling on how to write for the screen than you will from some advertising expert. And you’ll learn in a memorable and entertaining way – what could be better? There is one piece of advice he offers, in particular, about writing a scene that I love. || It’s a piece of advice that could be well employed by most writers: ‘Come in late, leave early’. || And Goldman’s not talking about the hours you keep. His point is that most writers leave nothing for the audience to do – the writer over explains. || When you write a scene, and it could be a screenplay or it could be a television commercial, whatever you do, you must leave room for the audience to participate. You have to get them engaged in the process – that way you’ll get them wanting more. || With screenwriting you move from scene to scene, twisting, turning and surprising, so predictability is the death of a screenplay, as it is for those of us who write television commercials.

If I can work out what’s coming why bother watching? Surprise is a fundamental factor in making something memorable.

Excerpt from:Β Hegarty on Advertising: Turning Intelligence into Magic by John Hegarty

πŸ’Ž Kleiner Perkin’s tactic for avoiding their staff developing entrenched positions in meetings (flip-flop)

Another renowned venture capitalist, Kleiner Perkins’s Randy Komisar takes this idea one step further. He dissuades members of the investment committee from expressing firm opinions by stating right away that they are for or against an investment idea. Instead, Komisar asks participants for a β€œbalance sheet” of points for and against the investment: β€œTell me what is good about this opportunity; tell me what is bad about it. Do not tell me your judgment yet. I don’t want to know.” Conventional wisdom dictates that everyone should have an opinion and make it clear. Instead, Komisar asks his colleagues to flip-flop!

Excerpt from: You’re About to Make a Terrible Mistake!: How Biases Distort Decision-Making and What You Can Do to Fight Them by Olivier Sibony

πŸ’Ž Contingent rewards can reduce intrinsic motivation (we are motivated by uncertainty)

Mark Lepper, David Greene, and Richard Nisbett (1973) conducted research on this question. They divided children into three groups:

  1. Group 1 was the Expected group. The researchers showed the children the Good Drawing Certificate and asked if they wanted to draw in order to get the certificate.
  2. Group 2 was the Unexpected group. The researchers asked the children if they wanted to draw, but didn’t mention anything about a certificate. After the children spent time drawing, they received an unexpected drawing certificate.
  3. Group 3 was the Control group. The researchers asked the children if they wanted to draw, but didn’t mention a certificate and didn’t give them one.

The real part of the experiment came two weeks later. During playtime the drawing tools were put out in the room. The children weren’t asked anything about drawing; the tools were just put in the room and available. So what happened? Children in the Unexpected and Control groups spent the most time drawing. The children in Expected group, the ones to had received an expected reward, spent the least time drawing. Contingent rewards (rewards based on specific behavior that is spelled out ahead of time) resulted in less of the desired behavior if the reward was not repeated. Later the researchers went on to do studies like this, with adults as well as children, and found similar results.

Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter)Β by Susan Weinschenk