Why Knowing About Bias Isn't Enough | Lesson 1.2, Free Course

A marble statue before a mirror; the room is sharp, its own reflection is blurred in red. Spotting bias in others is easier, seeing your own is the hard part. — Warnings, a short list, and a blind spot.

The idea

Researchers have tested many kinds of debiasing. In the studies behind this lesson, knowing about a cognitive bias did little on its own. In one set of studies, people still leaned on the first number they saw, even after a warning. Asking people to think of reasons they might be wrong corrected their judgments more. Telling them to be "as fair and unbiased as possible" corrected them less.
Even a good step can be overdone. Hindsight bias is feeling, afterwards, that an outcome could have been foreseen. In two studies, people who listed two other ways things could have gone showed no reliable sign of hindsight bias. People who listed ten showed more of it. So in those studies, a short list helped and a long one backfired.
Training has reduced some biases on the same kind of task, and in some studies the effect lasted for weeks. Whether it carries over to real-life decisions is still argued. People also see bias in others more readily than in themselves, which is called the bias blind spot. This held up when tested again in later experiments. People who scored higher on tests of thinking ability did not have a smaller blind spot. The evidence that training can shrink it is thinner.

Knowing and doing are different things.

In other words

Knowing about a bias is like knowing you often forget your keys. Knowing it doesn't put them in your pocket. A hook by the door does, because it works even on the days you forget.

Two children beside two block towers. Each can see that the other's tower leans; neither can see their own tower lean. — Two towers, and nobody sees their own lean.

Explain like I’m 5

Two kids build block towers side by side. Each can see that the other's tower leans. Neither can see their own tower lean, because they are too close to it. A grown-up standing back sees both. Adults call this the bias blind spot.

Two panels. Asking people to think of reasons they might be wrong corrected their judgments more than telling them to be as fair and unbiased as possible. — Checks that happen even on the days you forget.

How it applies

Taken together, the studies lean towards checks that are part of how you decide, instead of willpower. That is our reading. A step built into the routine happens whether or not anyone recalls the lesson. The drawing shows three such checks. The outside view looks at how similar past cases went; the inside view looks only at your own plan. And a second pair of eyes may see what looking inward misses.

Three built-in checks · Drawing: Hacks Vitae

A table comparing the inside view and the outside view: what each means, what it asks, what it is built from, and the 1994 studies. — Your plan says one thing. Past cases say another.

Inside view vs outside view

Compared	Inside view	Outside view
What it means	Forecasting from your own plan	Forecasting from how similar past cases went
What it asks	How will my plan go?	How did similar cases go?
Built from	Your own plans and scenarios	How similar projects went
In 1994 studies of predicting when tasks would be done	Predictions were too optimistic	The optimistic bias "was eliminated"

In those studies, the step was telling people to connect past experiences with their predictions.

Three hard questions, and the easier ones the mind may answer instead: could I be wrong, how long will this take, am I seeing this clearly. — Hard questions often get answered by easier ones.

If… then…

Examples (ours)

When a question is hard, the mind quite often answers an easier one instead, usually without noticing.

If the hard question is 'Could I be wrong about this?', the easier one is often 'Can I think of why I'm right?'
If the hard question is 'How long will this really take?', the easier one is often 'How long does my plan say it takes?'
If the hard question is 'Am I seeing this clearly?', the easier one is often 'Does it feel clear to me?'

Work, shops and friends.

Where you’ll see it

Everyday examples (ours)

At work: a plan is agreed in minutes, and nobody is asked to argue the other side.
Shopping: the first price you saw can still shape what feels like a deal, even when you know the trick.
With friends: you can see when a friend is too hopeful about a plan, and miss it in your own.

Three signs: a feeling that your own view is the balanced one, a reminder with no step attached, a forecast built only from your own plan. — It feels like being objective.

Signs it’s happening

A feeling that your own view is the balanced one, while other people's views look slanted.
A reminder like 'be objective' with no step attached to it.
A forecast built only from your own plan, with no look at how past cases went.

A sealed contract. I know about bias so I'm probably being objective, or what are one or two reasons this could be wrong. — Same purchase, one short list apart.

Before and after

Example (ours)

A big purchase that feels like the right call.

The quick answer

"I know about bias, so I'm probably being objective," and the purchase goes ahead.

The second look

"What are one or two reasons this could be wrong?" A short list, and a reason to wait may turn up.

An old notebook ruled into columns with black spots. Franklin added Humility after a friend told him he was generally thought proud. — A friend pointed out what the list missed.

Example from history: Franklin's chart

In his memoir, the Autobiography, the American printer Benjamin Franklin describes 13 virtues he set out to build.
He kept a chart and marked "by a little black spot, every fault".
His list began with twelve virtues. He added Humility after a friend told him he was "generally thought proud".
Of Humility, he wrote that he had little success with "the reality of this virtue, but I had a good deal with regard to the appearance of it."

Our framing

Franklin's story is about a virtue, not a thinking bias. Still, a friend pointed out what his list had left out. And knowing what to change did not finish the change.

Three words worth knowing.

Key terms

cognitive bias: A systematic, common tendency that skews judgement or decision-making in the same direction, in ways that can make the outcome inaccurate or less than ideal. Glossary →

debiasing: Efforts to reduce or remove the effect of a thinking bias on judgements and decisions. Glossary →

bias blind spot: The tendency to see yourself as less influenced by biases than other people are. Glossary →

Quick check3 questions · nothing is saved

1. In the studies, what corrected people's judgments more than being told to be fair?

2. In the two hindsight studies, what did listing ten other ways things could have gone do?

3. What is the bias blind spot?

For more: the research behind it

Optional. Everything above stands on its own; these are the full articles, with every source.

The statue shines its phone torch on the mirror. What are one or two reasons I could be wrong?

One question worth keeping.

In one line

Knowing a bias names the problem; one or two reasons you could be wrong give you a way through.

Whose blind spot have you been sure you could see, and what might they see in yours?