Posted by: Kash Farooq | April 28, 2011

Bad decision making and the framing effect

I recently attended a Science London talk given by UCL Neuroscientist Dr Benedetto De Martino. The talk was titled “Decisions, Decisions, Decisions” and was about a phenomenon called the framing effect.

Due to the framing effect, the same option presented in different formats can change the decisions people make. This effect can influence anyone. It is particularly interesting when dealing with how risk is presented in medicine; present identical data differently and doctors can be influenced about the worth of a treatment.

Basically, the way a question is framed can influence how the question is answered.

There is a famous example that Dr. De Martino mentioned in his talk. It is from the 1981 paper “The Framing of Decisions and the Psychology of Choice” [PDF] by Amos Tversky and Daniel Kahneman:

Imagine that the U.S. is preparing for the outbreak of an unusual disease, which is expected to kill 600 people.  Two alternative programs to combat the disease have been proposed. Assume that the exact scientific estimates of the consequences of the programs are as follows:

  • If Program A is adopted, 200 people will be saved.  [72 percent]
  • If Program B is adopted, there is ⅓ probability that 600 people will be saved, and ⅔ probability that no people will be saved. [28 percent]

The percentages responses are given in brackets. Program A is a clear winner with 72% of the respondents selection this option.

Now the question is asked differently – i.e. it is framed differently:

  • If Program C is adopted, 400 people will die. [22 percent]
  • If Program D is adopted, there is ⅓ probability that nobody will die, and ⅔ probability that 600 people will die. [78 percent]

This time, Program D is the clear winner with 78% of respondents selecting it.

However, Program B is identical to Program D. Also, Program A is identical to Program C. By just framing the question differently, you can get a completely different response.

This is rather worrying. It seems to be very easy to confuse people with data. An advertiser’s dream situation!

Is bad decision making evolutionary?

Bad decision making isn’t restricted to humans.

Decision-making has been studied in monkeys and it appears that the same mistakes are made by our primate cousins. Specifically, capuchin monkeys have been studied. They are New World primates – our last common ancestor lived about 35 million years ago.

Capuchin monkey

White-faced capuchin monkey in Manuel Antonio National Park in Costa Rica, by Michelle Reback

An experiment was designed that introduced currency tokens into their monkey world. The monkeys quickly learnt that they could hand tokens over to the different humans in the lab in return for grapes.

Next a marketplace was created in which different humans provided different deals. For the same amount of currency, one human would give more grapes than another. Again, the monkeys quickly learned to go to the guy who was cheaper.

Finally an element of risk was introduced. The monkeys were introduced to two salespeople who both appeared to be selling 3 grapes per token. However, one of the salespeople took away one grape every single time when handing over the products – the monkey always received 2 grapes. The other salesperson randomly took away either zero or two grapes – the monkey could end up with either one grape or three.

So what do the monkeys do? Play it safe and always pick the guy who guarantees a 2 grape return. No, they play risky and go with the other guy.

And this is exactly the same thing that humans do when presented with a similar situation.

So perhaps we can’t blame the bankers for the financial collapse? Perhaps risk taking in the financial markets is a consequence of evolution?

Nah…let’s still blame the bankers.


I highly recommend you watch the full capuchin monkey TED video presented by Laurie Santos. She’s informative and very entertaining. Her talk covers other discoveries such as the monkeys would try to steal tokens at every opportunity.


This post was originally published on the Birmingham Skeptics website. It was also recorded for episode 74 of the Pod Delusion – a podcast about interesting things.


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