A book given to people taking the GRE exam advises them that “Exercise great caution if you decide to change an answer. Experience indicates that many students who change answers change to the wrong answer.”
This advice represents a widespread belief that our instincts, our intuitive senses, are the most reliable guides to decisions. It is based on the assumption that instincts are based on prior knowledge and experiences and that our brains integrate all these things to enable us to make quick judgments that tend to be sound. This is the idea heavily promoted by Malcolm Gladwell in his book Blink.
But is it true?
I was interested in this study (published in the Journal of Personality and Social Psychology, 2005, Vol. 88, No. 5, 725–735 by Justin Kruger, Derrick Wirtz, and Dale T. Miller) titled Counterfactual Thinking and the First Instinct Fallacy (subscription required but you can see a fairly detailed discussion of the paper < a href="http://www.apa.org/monitor/apr05/instincts.aspx">here) that examined the answers given by 1561 students in response to a multiple choice test. By looking at the erasures and comparing them with the final answer, they found that 51% changed their answers from wrong to right, 25% from right to wrong, and 23% from wrong to wrong. In other words, when people changed their minds, they were twice as likely to go from wrong to right as from right to wrong.
In fact, the authors point out that research over a period of 70 years provides overwhelming evidence that these ‘second guesses’ are more likely to be correct. So given this clear evidence over a long period of time that second guessing leads to better outcomes, why do people still think that sticking with the first choice is the best option?
As I have written before, our initial reactions are based on System I thinking that “operates automatically and quickly, with little or no effort and no sense of voluntary control” and does not engage the higher order thinking skills that are brought in by System 2 which is slower because it “allocates attention to the effortful mental activities that demand it, including complex computations” (Thinking Fast and Slow, Daniel Kahneman, 2011, p. 20). Most of the time when confronted with novel problems, we tend to form an initial response based on the quick intuitive System 1 thinking instead of taking the time to engage the slower but more analytical System 2 thinking because it requires less intellectual effort. We tend to use System 2 only when we are forced to do so, even though it gives better results. But when we ‘second guess’, we are more likely to be using the more reliable System 2.
But there is more to the desire to stick with our first guess than the tendency to avoid intellectual effort. In a separate experiment that involved only 23 students (but still has p<0.05), Kruger, Wirtz, and Miller found that people feel worse when they change a correct answer to an incorrect one (74%) than when they stick with an original incorrect answer (0%!). 26% felt that they would feel no difference in regret. Furthermore, students who switched from a correct answer to an incorrect one were far more likely to remember it later. All these make changing right answers to wrong more memorable than a wrong-to-right change and since we tend to assign higher probability to more easily recalled events, this makes it seem far more probable that second guesses lead to wrong decisions than it really is.
This might also explain the psychology behind the anomalous results of the Monty Hall problem. Most people are aware of this game. There are three closed doors, behind one of which is a valuable prize, while the other two have nothing. People are asked to pick a door. After they have chosen, the door is not opened but one of the remaining two doors is opened to reveal that there is nothing there. The contestant then has the option of sticking with the first choice or switching to the remaining unopened door.
Statistically, you are better off switching than sticking with your first choice. This is because there is a 2/3 chance that your first choice was wrong (since you had three options then)
but only a ½ chance that switching would result in the wrong door (since you now have only two options) and so it is twice as likely that the prize was behind one of the other doors. Opening one of them later does not change those odds.
But most people stick with their first choice. Why? Part of it is undoubtedly due to a misunderstanding of statistics. They think that since there are only two choices after one of the doors is opened, it is 50-50 as to which of the two remaining closed doors conceals the prize so it does not really matter. But even then, you would expect half to stick with the first choice and half to switch but that is not the case.
One can put this down to inertia. Why switch if there is nothing to be gained? But there is more to it than that and the psychology behind not switching is not hard to understand. It is because people regret more those things they had and then lost than those things they never had in the first place. This desire to avoid loss is very strong. In the Monty Hall problem, if it is revealed that they switched from the right choice to the wrong one, this is accompanied by the feeling that they had the valuable prize in their grasp and then threw it away, whereas if they stick with their choice and it is wrong, they feel that they never really had the prize in the first place.
So the reason that we are reluctant to change our minds once we have made even a quick and hurried decision is driven by our desire to avoid the great feeling of regret that we had it right and then blew it.