= 擁有偏誤

• People tend to value items that they own more highly than they would if they did not own the same items.
• People often demand more to give up an object than they would be willing to pay to acquire it.

This bias makes us resistant to change and overly attached to the status quo, even when better options exist.

[@kahnemanExperimentalTestsEndowment1990]

In 1990, behavioral economists Richard Thaler, Daniel Kahneman, and Jack Knetsch conducted an experiment using a simple coffee mug.

They split the participants into two groups:

• Sellers: Given a coffee mug and told they owned it.
• Buyers: Given nothing and told they could buy a mug if they wanted to.

Then, the researchers asked each participant a question:

• Sellers: What is the minimum price you’d be willing to sell the mug for?
• Buyers: What is the maximum price you’d be willing to pay for the mug?

The results were fascinating:

Sellers wanted $7 on average to sell the mug, while Buyers were only willing to pay$3 on average to buy a mug.

The mugs were all identical in every way, but the two groups placed very different value on the item.

This revealed a striking cognitive bias: The Endowment Effect.

The Endowment Effect describes our tendency to assign more value to things simply because we own them. Once people possess something, they value it more highly, purely because it’s theirs.

It provides the scientific basis for an irrational attachment to the things that are ours.

Examples

• You keep old clothes you never wear simply because they’re already in your closet.
• People are reluctant to sell a house at a loss, even if it’s the rational choice, because they “own” it.
• Companies overvalue patents or products they developed, even when the market says otherwise.

Related Biases

• Loss Aversion
• Status Quo Bias
• Sunk Cost Fallacy
• Anchoring Effect

How to Overcome

• Imagine you don’t own the item: Would you buy it again at the current price?
• Seek outside perspectives—ask what a neutral third party would do.
• Practice detachment: Remind yourself that value is not inherent, but assigned.
• Use probabilistic thinking: Consider the odds that keeping something will actually benefit you in the future.