Anchoring Effect — The First Number Changes Everything That Follows

## The Core Finding

When making numerical estimates, people are disproportionately influenced by the first number they encounter — even when that number is arbitrary.

Tversky and Kahneman (1974): They spun a wheel of fortune in front of participants before asking them to estimate what percentage of African nations were in the UN. People who saw the wheel land on 65 gave significantly higher estimates than those who saw it land on 10.

The wheel was random. The participants knew it was random. The anchor still worked.

## How Anchoring Works

The dominant explanation: **insufficient adjustment**. People start from the anchor and adjust, but don't adjust enough. The anchor constrains the range of plausible values even when it shouldn't.

A second mechanism: **selective accessibility**. The anchor activates anchor-consistent information in memory. If told the Eiffel Tower is 1000 feet tall, you retrieve memories consistent with tall structures. The background information shifts, not just the estimate.

## Real-World Applications

**Salary negotiation**: The first offer anchors the negotiation. Studies show whoever makes the first offer tends to get a better outcome.

**Retail pricing**: "Was $200, now $99" sets the original price as an anchor. The $99 feels like a bargain even if $99 is the market price.

**Legal damages**: Research found that when plaintiffs stated higher demands in personal injury suits, juries awarded higher damages — even when instructed to ignore the demand.

**Real estate**: Asking prices anchor appraisals. Professional agents shown the same house with different listing prices made different "independent" appraisals that tracked the listing price.

## Anchoring in Expert Domains

Englich and Mussweiler (2001): Experienced criminal judges who received a high sentencing request from a prosecutor gave significantly longer sentences than judges who received a low request — even when the request was generated randomly.

Expertise reduces anchoring in some domains (doctors and base rates) but not others (judges, financial analysts, negotiators). The critical factor is whether the domain provides frequent, clear feedback that corrects the bias.

## Debiasing Approaches

**Consider the opposite**: Before finalizing an estimate, generate reasons why the anchor might be wrong. This consistently reduces anchoring without eliminating it.

**Use multiple anchors**: Several reference points from different sources dilutes the effect of any single anchor.

**Set your own anchor first**: Before seeing someone else's number, write down your estimate. This creates a competing anchor.

**Slow down**: Anchoring effects are stronger under cognitive load. Time pressure increases anchor dependence.

Anchoring operates at the level of information processing, not reasoning. You can know about it, intend to ignore it, and still be influenced. The correctives work by creating additional cognitive steps that force more adjustment — not by removing the bias.

Anchoring Effect — The First Number Changes Everything That Follows

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