Lesson preview · Behavioral Economics
Framing Effects & Biases
~5 min · Free to read
If people were perfectly rational, the way a problem is described shouldn’t affect their choice — only the underlying outcomes matter. But Kahneman and Tversky showed that framing — how options are presented — systematically changes decisions. This violates a basic axiom of rational choice theory (description invariance) and reveals deep cognitive biases.
Key Term
Key Framing Effects and Biases
- Framing effect: People choose differently when the same problem is framed as a gain vs. a loss. E.g., “90% survival rate” sounds better than “10% mortality rate” — same information, different choices.
- Anchoring: Initial information (even irrelevant) biases subsequent judgments. Asked “Is the population of Turkey more or less than 5 million?” people guess lower than when asked “…more or less than 65 million?”
- Endowment effect: People value things more once they own them (loss aversion applied to objects).
- The 2/3 game: Guess 2/3 of the average guess (0-100). Rational equilibrium is 0, but real play averages 20-30 due to limited levels of reasoning.
Description invariance: rational agents should choose the same regardless of how options are framed. Humans violate this systematically.
The classic demonstration is the Asian disease problem (Tversky & Kahneman, 1981). A disease threatens 600 people, and a public health official has to pick a program to fight it.
Group one is told: Program A saves 200 people for sure. Program B has a 1/3 chance of saving all 600 and a 2/3 chance of saving no one. Most people pick the certain Program A — risk-averse, because the choice is framed as gains (lives saved).
Group two is told: Program C lets 400 people die for sure. Program D has a 1/3 chance that nobody dies and a 2/3 chance that all 600 die. Most people pick the gamble in Program D — risk-seeking, because the choice is framed as losses (lives lost).
But Program A is identical to Program C, and B is identical to D. Only the wording changed. Flipping the frame from “lives saved” to “lives lost” reversed the choice. This is the prospect-theory value function in action: concave in gains, convex in losses.
Worked Example
In the 2/3 game, 100 players each guess a number from 0 to 100. The winner is the person closest to 2/3 of the average guess. What is the Nash Equilibrium? Why do actual results differ?
The Asian disease problem reveals a deeper idea: reference points. Group one’s baseline was “everyone dies” — so saving 200 felt like a gain. Group two’s baseline was “everyone lives” — so 400 dying felt like a loss. Same outcomes, different baselines, opposite choices.
A reference point is the dollar amount (or outcome level) your brain treats as “zero” or “status quo.” Above it, you feel a gain. Below it, you feel a loss. It’s almost never just “total wealth” — it’s set by expectations, recent experience, or how the question is framed.
In the widget below, slide the reference point R around. The fixed outcomes on the curve don’t move — only the baseline does. Watch them flip between gain-coloured and loss-coloured as R crosses them.
Tip
Reference points in everyday life
Same paycheck, opposite feelings:
- A salesperson expects a 10% commission and gets 6%. Disappointed.
- Their colleague expects 5% and gets 6%. Thrilled.
The reference point is doing all the work. More examples:
- Your portfolio hit 100k last month, now sits at 90k. You feel a loss — even if you started the year at 80k.
- A “free shipping” label feels like a win compared with “shipping included in the price.” Identical money, different framing, different reference point.
- Tax season: people who get a refund feel a gain, people who owe feel a loss. Same money flowed out of their paycheque all year either way; only the baseline they’re comparing to differs.
Check yourself · no marks
How can understanding framing effects be useful for policy design?
Commit to one first. Guessing and being wrong beats reading the answer cold.
Practice · 1 / 4
The endowment effect is explained by:
Next
Like what you read?
Sign up free to save your progress, get spaced reviews tuned to you, and unlock all 50 microeconomics knowledge points with interactive graphs and adaptive practice.