Oddly Wired
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decision making

Your initial estimate is a trap you set.

A 1974 study showed that people's final estimates for unknown quantities are heavily skewed by the first arbitrary number they hear.

Even when participants were told the anchor was random, their final guesses moved toward it. You adjust away from the first data point you encounter, but rarely far enough.

The first number you see sets the ceiling for your thinking.

Where this comes from

Study
Tversky and Kahneman, 1974, Anchoring Bias
What the check found
The 1974 Tversky and Kahneman study used a rigged wheel of fortune (a random process) as an anchor. While the claim is accurate to that study, replication of 'random anchor' effects is debated in modern literature.
Confidence
Solid, with limits

Related

One of these every day, and every one names the study it came from. When a finding is contested, it says so.