February 7, 2022 Leave your thoughts

The persuasive power of choice

A short commentary on Bown, Read and Summers. The lure of Choice. JBDM 2003

In our previous post, we saw that rats’ behaviour indicates that they value choice in and of itself. Since this discovery by Voss and Homzie in 1970, many others have shown similar behaviours in other animals including pigeons, monkeys and humans. The idea that choice can be inherently valuable raises a curious and potentially powerful prediction: 

It should be possible to manipulate people’s preference between two products of the same value: people would prefer product A over B if A is offered as part of a choice bundle with a third, inferior item C.   

Nicola Bown, Daniel Read and Barbara Summers conducted a great experiment to test this very exciting prediction. 

They asked their participants to imagine that they were at a casino with roulette tables. Half of the participants went to Casino Royal. The other half to Casino Republic. The participant was given one chip to play in one roulette game.  

You are about to leave and you have one token left. Near the exit there are two tables offering a chance of winning a prize. You can get one spin of the wheel in exchange for your token, and if the pointer ends up in the light section, you win the amount specified. Choose the table at which you would like to spend your token.” 

For participants in Casino Royal, there were two spinners A and C on the Green table and one spinner B on the sky blue table (see Figure 1) .   

For participants in Casino Republic, spinner A was on the Green table and spinner B and C were placed on the sky blue table.

Figure 1. Left panel shows the prize amount and probability of winning for each spinner. Right panel shows the organisation of the options in each casino. The numbers below each table indicate the frequency that participants chose that table.

As depicted in Figure 1, left panel, spinners A and B had very similar expected values (i.e., probability of reward x reward size) of ~2.2£ and spinner C had a lower expected value of 1.8£. This means that a rational decision maker who looks for the best prize to win should be indifferent between the green and blue tables. After all, the participant has only one token and in both casinos, the better options of the green and sky blue tables are identical. 

The results (see numbers underneath each table in Figure 1) showed that this was NOT the case. In each casino, the majority of the participants preferred the table with a choice.

As predicted above, Bown, Read and Summers showed that it is possible to manipulate people’s preference between two products of equal value (A and B) by bundling one or the other with an inferior product C. The eagerness to have a choice makes us predictable. 

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