Biases and effectsKahneman, Knetsch and Thaler, 1990
What you own looks worth more than it did before you owned it. The same mug doubles in price the moment it is yours.
Students were split in two. One group was given a university mug. Owners were asked the lowest price they would sell for; non-owners, the most they would pay.
Sellers' median: about $7. Buyers': about $3. Same mug, more than double.
The mugs had been handed out minutes earlier. No memories, no attachment. Yet the instant it became "mine", the price to let it go jumped.
The root is loss aversion: losing something hurts about twice as much as gaining the same thing feels good.
Owners price it as a loss; non-owners price it as a gain. Same object, seen from opposite sides of zero. So the prices never meet.
This is also why second-hand listings sit unsold: the seller is pricing a loss, the buyer a gain.
Re-ask it as: "if I did not own this, would I buy it at this price?" If not, the reason to keep it is thin.
Decluttering mostly resolves with this one question. Not "would I throw it out" but "would I buy it again".
When you are the seller, assume your price is running about double and discount from the start.
The unsold listing
A listing that has sat for a month is priced as a loss to you, not a gain to them. The reasons it "deserves" the price usually make sense only to the owner.
Cancelling the free trial
Before the trial it was "probably not needed". After a month it is "cannot do without". The features did not change; the decision flipped from gaining to losing. Free trials exist to buy this effect.
The clothes you cannot let go of
Clothes unworn for two years: would you buy them today, in a shop? If not, you are storing them, not wearing them. "Still wearable" is not a reason to wear; it is a way to avoid the sting of letting go.
If you take one thing
"It is valuable because I own it" usually runs the other way: it looks valuable because you own it. Ask whether you would buy it again, and things get lighter.
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