The fundamental attribution error is the attribution of the source of behaviour to the character and personality of a person above the consideration of context. It's sometimes described as over-attributing causes to disposition over situation.

In a classic example, if a driver swerves in front of you suddenly, it's easy to attribute the cause of the behaviour to the driver being a jerk, i.e. to their character. What we may not see is that the driver is late to pick up their kids, was distracted by a challenging conversation they just had at work, and they're worried they've gone the wrong way and are driving an unfamiliar car.

If a colleague is late to meet us, we might infer that the person is lazy or disrespectful when, in fact, they may have been held up by a traffic accident, been on the phone with a sick relative, and have had trouble sleeping lately. If we are late for a meeting, well, then it's probably for all sorts of good reasons outside our control.

Like confirmation bias, the fundamental attribution error is a big one that can easily colour our interactions with others without us being aware of it.

Remember that what we see is just a tiny fraction of any other person's life and that we don't see the complete picture.

Minimise judgment, particularly around character and personality.

Where appropriate, ask if anything is bothering others.

Build empathy for others as you would for yourself.

Reflect on the positive things others do.

The Fundamental Attribution Error

The Barnum effect is our tendency to apply personal meaning to statements that could apply to many people.

For statements such as the results of a personality test, the effect is stronger if:

they are sufficiently vague — handy phrases include "at times," "a tendency to," "some of," etc.

they are mostly positive — we're more inclined to accept positive evaluations of ourselves than critical ones

You may recognise these tricks from a horoscope or your star sign, magicians, fortune-tellers, fortune cookies, con artists and, perhaps, marketing. There's a fascinating magician's technique you may have seen called cold reading that uses the Barnum effect with other tricks ("I see someone with heart pain in your family.") to make it seem like they know a lot of personal details about someone at a first meeting.

Originally from Bertram Forer, who called it "the fallacy of personal validation," it was later known as the Forer effect until Paul Meehl suggested it should be named the Barnum effect after P. T. Barnum (now of The Greatest Showman fame) for the way he could easily fool an audience with these techniques and to emphasize that we should all know and be on the lookout for being fooled. For that reason, I called it the same here.

Bertram Forer ran an experiment with his students (pdf), giving everyone the same results for their individual personality assessment. Generally, the students all thought the same description applied very well to themselves. He used these statements taken "largely from a newsstand astrology book":

You have a great need for other people to like and admire you.

You have a tendency to be critical of yourself.

You have a great deal of unused capacity which you have not turned to your advantage.

While you have some personality weaknesses, you are generally able to compensate for them.

Your sexual adjustment has presented problems for you.

Disciplined and self-controlled outside, you tend to be worrisome and insecure inside.

At times you have serious doubts as to whether you have made the right decision or done the right thing.

You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations.

You pride yourself as an independent thinker and do not accept others' statements without satisfactory proof.

You have found it unwise to be too frank in revealing yourself to others.

At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved.

Some of your aspirations tend to be pretty unrealistic.

Security is one of your major goals in life.

I learned about it from a discussion of the Meyers-Briggs test (I'm an ENTP btw).

Here's Paul Meehl advocating for the Barnum effect:

"Many psychometric reports bear a disconcerting resemblance to what my colleague Donald G. Paterson calls “personality description after the manner of P. T. Barnum” ... I suggest—and I am quite serious—that we adopt the phrase Barnum effect to stigmatize those pseudo-successful clinical procedures in which personality descriptions from tests are made to fit the patient largely or wholly by virtue of their triviality; and in which any nontrivial, but perhaps erroneous, inferences are hidden in a context of assertions or denials which carry high confidence simply because of the population base rates, regardless of the test’s validity. I think this fallacy is at least as important and frequent as others for which we have familiar labels (halo effect, leniency error, contamination, etc.). One of the best ways to increase the general sensitivity to such fallacies is to give them a name. We ought to make our clinical students as acutely aware of the Barnum effect as they are of the dangers of countertransference or the standard error of r."

Meehl, P. E. (1956). Wanted—a good cook-book. American Psychologist, 11(6), 263–272. https://doi.org/10.1037/h0044164

The Barnum effect

Attribution bias includes a set of more specific biases where we may attribute behaviour to fixed personality traits or characteristics of a person rather than specific circumstances or actions.

For example, a child may be labelled a genius or gifted when they actually had a supportive environment and worked hard, or someone may be labelled a loser rather than recognising specific circumstances that led to some failures.

Criticism — one of the four horsemen of relationship apocalypse — can become toxic when it's attributed to someone's personality traits. For example, calling someone 'lazy' rather than sharing how it makes you feel when they don't keep the place tidy.

A form of attribution bias may be applied to whole societies via the Destiny Instinct.

Specific examples of attribution bias include the fundamental attribution error and self-serving bias.

Attribution bias

Optimism bias is believing things will turn out well despite past evidence or circumstances.

It can be extremely helpful. It allows us to attempt things that many may deem impossible. It probably helps motivate entrepreneurs even when everyone doubts them. Optimists are often healthier and happier.

We might overestimate our chances of success because of what we want to happen rather than what's likely to happen.

We may feel pressure from others to give a rosier outlook — like when you might underestimate a timeline when speaking with your boss.

We might want others to succeed, or they may be paying us money and hoping for good news.

We probably think we'll get more done next week. 

We probably think we'll be more disciplined than we will be.

We might think that this time it'll be different or that everyone can't be wrong.

Or we may be just discounting evidence without realising it.

Optimism bias

We're all different sizes, and there is no one-size-fits-all, but when it comes to the chosen size it turns out that that size mostly fits men better.

Caroline Criado Perez in her book Invisible Women shares how so much of the designed world fits men better than women — examples include piano keyboards that make playing more technically difficult and more prone to injury for smaller hands, stab vests that didn't take account of breasts, crash test dummies for car seats tested only with males, toilets that always lead to queues, phones that don't fit female hands or pockets, and voice recognition that picks out male voices more easily.

It's a stark reminder of how we need to do more to design with more of the world in mind rather than the default reference male. 

Read more: The deadly truth about a world built for men – from stab vests to car crashes.

See also brilliance bias and the curb-cut effect.

One-size-fits-men

Don't ask the barber if you need a haircut — a simple reminder that asking someone with a vested interest in the outcome isn't likely to give you an impartial answer.

Except that while we might reasonably make decisions about our hair with few consequences to anyone but ourselves, when we work with professionals they may well see or hear what we don't. It might be that asking a professional to review what you're doing is exactly what you need to tell you what you didn't and couldn't think to ask.

The phrase has been famously shared by Warren Buffet though it appears in several similar earlier forms.

Don't ask the barber if you need a haircut

Confirmation bias is the big one. The bias that leads us to live in a world of our own choosing, finding the information that already fits with our beliefs and ignoring or discounting what doesn't. It's the bias that makes two sides get further apart rather than closer together.

Edward De Bono in Water Logic suggested a metaphor for thought as channels of water. As water runs through the channels the channels get deeper, and as they get deeper it pulls more of the water into the main channels until there is only one way. Confirmation bias can act like that.

It's important to work to understand different opinions, not discount them upfront. To use our empathy to understand why others feel the way they do. And when we deliberately seek out information that challenges our point of view we will usually find a richer, more nuanced world that helps build bridges with others rather than drive us apart.

Confirmation bias

There are a lot of reasons why it can make sense to go with the majority. Going with the popular view is a shortcut for taking the time and effort to make our own decisions from scratch. We might reason that if others believe it, then it's probably true. But we can also keenly feel the desire to conform to the majority view because it's uncomfortable to hold a different opinion — the easy choice is so often to go with the flow even if, deep down, you disagree. So we get the bandwagon effect.

The bandwagon effect can lead to the Abilene paradox — where a group can make a decision that no one in the group agrees with. On a night out it may lead to just following the crowd, but in a company it could lead to launching a product that no one thinks is good or, more seriously, in safety critical industries like airlines, if people don't feel comfortable speaking up against the group or authority it could lead to accidents.

The bandwagon effect

So the story goes, as told by Stephen Sigler, Nature May 1989:

"The US military studied fighter planes returning from missions to try to improve their survival rate and were considering adding heavy armour to those parts of the plane that tended to show the greatest concentration of hits from enemy fire, until statisticians pointed out the fallacy of that argument. The more vulnerable parts of the plane were those with the fewest hits; planes hit there tended not to return at all. The single most vulnerable part, the pilot’s head, was without serious scar in the sample of planes that returned."

It’s easy to draw correlations from what we see in front of us. But what we see usually represents just a small part of what has happened. Focusing on the evidence we can easily see at the expense of that we can’t leads to survivorship bias. To say it another way, when Bill Gates drops out of college and starts Microsoft it might seem like dropping out is a path to success for others too, but that ignores all the dropouts who didn’t create Microsofts and consequently you didn’t hear about.

Silent evidence — the evidence that we don’t or can’t easily choose to consider — is a term from Nicholas Nassim Talleb.

When trying to discover the veracity of the planes story I enjoyed Bill Casselman’s American Mathematical Society article on The Legend of Abraham Wald. The postscript points to some of the source behind the story including a mention of Stephen Sigler’s letter in Nature quoted above.

I covered survivorship bias before, but I like this story so much I thought it was worth doing again.

Survivorship bias

Fading affect bias is the name given to the fact that the intensity of emotion, or the affect, of our bad memories seems to fade faster than for our good memories.

This means that, say, our happy memories keep us happier for longer, and our bad memories don’t affect us as much in the future. It’s called the fading affect bias, as the fading is biased more strongly for negative memories.

This is handy as it naturally gives us a more positive disposition. So, for instance, after some time has passed, we may find we remember the good parts of a holiday — like an amazing beach — more clearly than the bad — like the mosquitoes at the beach. And thinking about the good parts keeps making us happy longer than thinking about the bad parts might make us sad. Brilliant!

This is a different use of affect than the common affect/effect confusion.

Fading affect bias

The Implicit Association Test (IAT) is an amazingly simple way to uncover if and how strong your implicit biases may be. For example, you could test if you have a bias on gender roles (as in the sketch), race, religion or in fact any attitudes you may have. You could forget about reading this and simply go take the Implicit Association Test online now and you’ll get the idea and perhaps surprise yourself.

In the example I gave in the sketch, you could see how strong your biases are for traditional gender roles by measuring the difference in time it takes to sort first career words towards men and home and family words towards women, and then sorting the other way around.

It’s fascinating, and a little uncomfortable, to see your implicit attitudes so clearly come to light. Don’t forget to try taking a test.

The Implicit Association Test

The IKEA effect is the increase in value we feel towards self-made products—products that required our effort to create them. Or, less formally, we love it more if we made it.

The effect is named after the odd sense of satisfaction many of us feel after spending more time and sweat than expected putting together IKEA's famous flat-pack creations. Yet not only does more effort equal more love. If we've put effort into something ourselves, we're also more likely to, often mistakenly, think that others will value it more, just as we do.

Together with others, Dan Ariely, a professor of behavioral economics, conducted several experiments leading to these conclusions.

Ariely also points out that kids are the ultimate expression of the IKEA effect: they're very hard, don't come with instructions and take a lot of effort.

Watch Dan Ariely do a great job explaining some experiments that lead to this conclusion, or read the full paper, The “IKEA effect”: When Labor Leads to Love (pdf), Norton, Mochon, Ariely HBS working paper, 2011.

The Betty Crocker Effect, or ‘the egg theory.’

The IKEA effect

The reason, generally, is simply that all those times previously, we weren’t tuned in to notice what’s top of mind now. The frequency likely hasn’t changed a bit, but our noticing of it has.

Also known as the Baader-Meinhof Phenomenon.

The frequency illusion: we notice what’s top of mind

Update: More recent research has brought into question the captivating notion of ego depletion with difficulties reproducing some key experiments and suggesting other factors may be at work.

In his book You are now less dumb, David McCraney explains an concept called ego depletion with the basic idea that our brains require fuel, particularly the decision-making and glucose hungry pre-frontal cortex. Every time you have to make decisions or deal with difficult situations it tires you such that we have a sort of finite amount of will power. If you spent the morning battling to get the kids dressed and out the door, then jostling your way through a crowded commute, by the time you get to work you’re more likely to say ‘whatever’ to any decisions that come your way. Making decisions is hard work.

McCraney brings up a remarkable, and slightly disturbing, study by Shai Danziger which followed eight Israeli judges as they decided on over 1,000 parole applications. The findings show that prisoners were most likely to be granted parole first thing in the morning, after a snack break, and right after lunch. If you were unlucky enough to be up for parole just before lunch, bad luck.

If you want the most control over your own mind so that you can alter your responses to the world instead of giving in and doing what comes naturally, stay fresh. Take breaks. Get some sleep. And until we understand what ego depletion really is, don’t make important decisions on an empty stomach.

Here’s a nice summary of Shai Danziger’s parole study in the Economist including a remarkable chart.

Don’t make important decisions on an empty stomach

Dan Kahneman and Amos Tversky’s behavioural economics theory modeling how we make decisions. It illustrates, among other things, some of the non-rational decisions we make as we are guided by emotion and heuristics in decisions. The sketch points out a few of the key points:

Loss aversion - the different shape of the curves as we make gains or losses (either side of the centre) represents how a loss of £100 annoys us much more than a gain of £100 gives us pleasure.

Diminishing sensitivity - the levelling off of the curves represents that we’ll enjoy winning £100, if we only have £100, much more than we’d enjoy winning £100 if we had £900.

Adaptation level - We don’t evaluate from some absolute level - we evaluate whether something is good or bad from a neutral reference point that we adapt to. So, by the end of a movie the movie theatre doesn’t feel dark, yet walking out feels blinding. Your reaction to the £100 example above was probably affected by whether you think £100 is a lot of money or a little, which is all to do with your adaptation level.

Prospect theory

Unfortunately, there are studies to show that this is generally true, and prices written smaller are seen as more affordable than those written larger.

What with decoy prices, anchoring, the age-old susceptibility to 99s and a host of other biases, we’re at the mercy of many factors when it comes to trying to make vaguely rational pricing decisions.

For plenty more see William Poundstone’s, Priceless: The Myth of Fair Value (and how to Take Advantage of It), Scribe, 2010.

Prices written smaller seem more affordable

The technique of adding a significantly more expensive option in order to instantly make the other options look reasonable by comparison. These kinds of manipulations have been shown to be scarily effective.

Pricing decoys are another way retailers get you to part with more money than you planned on. In his book Predictably Irrational, behavioural economist and professor Dan Ariely demonstrates how a large magazine successfully employed a strategy called the “decoy effect” to increase revenue from subscription sales. Prospective subscribers were given three choices:

1.       Web-only subscription for $59
2.       Print-only subscription for $125
3.       Web + print subscription for $125

At first glance, the middle price point appears to be superfluous. Why would anyone buy a print-only subscription for $125 if they could get a web and print for the same price? Ariely tested the price points with MIT students and found that 16% of students chose option 1 and 84% chose option 3; not surprisingly, none chose option 2.

Then Ariely did something really interesting; on the assumption that having a decoy price (option 2) was influencing people’s choices, he removed the decoy and retested the price points. This time, the subscription choices were as follows:

1.       Web-only subscription for $59
2.       Web + print subscription for $125

With the decoy removed, the option that had previously been the most popular – the more expensive print + online access subscription – suddenly became the least popular choice. Only 32% of those surveyed chose the more expensive option, with 68% selecting the online-only subscription. Clearly the middle price point wasn’t superfluous; it was smart marketing that made option 3 look more attractive to subscribers.

Avraham Byers, Here’s why you should always pay full retail price, Financial Post, April 22nd 2014

The decoy price

Where “all the children are above average.” From the intro by Garrison Keillor to the News from Lake Wobegon on the radio show A Prairie Home Companion. Also known as illusory superiority. From the popular studies where, for example, 80% of people think they are above average drivers, when asked to estimate the % of chores done in the household it adds up to more than 100%, and we overestimate our input to project work and it’s impact on its success. For the best treatment I’ve read, and references, see Thinking Fast and Slow by Dan Kahneman.

The Lake Wobegon Effect

We usually only see the winners. The losers tend to disappear from the record. Which is why all the fund managers in the papers seem to be giving great returns, or starting the next Whatsapp or Instagram seems like such a sure fire way to get rich. We don’t see all the funds, apps and entrepreneurs who never made it.

Hindsight bias, Loss aversion and Recency bias. Parents in particular frustratingly seem to suffer from hindsight bias where everything becomes blindingly obvious as soon as a child has dropped the glass/fallen over/bumped into someone. Though ‘careful’ is not so useful after the fact.

Sneaky cognitive biases: hindsight bias, loss aversion, recency bias

Anchoring

Stories feel better than randomness — even when randomness may be the truth. Another reason that reading the papers is not always worth your time. This TEDx talk has a nice summary of a host of our common cognitive biases.

Narrative bias

Framing

We’re not very consistent at estimating the future value of something and have a bias, perhaps motivated by survival, towards overvaluing nearer outcomes at the expense of later ones.

Hyperbolic discounting

We have a tendency to think that we’ll be able to act differently in the future. So while this lucky chap plans to start his diet tomorrow having been presented with this giant cake, he underestimates his likelihood of not sticking to it on future days.

Bias sketches