Critical Thinking (Part 2 of 4)

Each day, we risk information overload, yet we’re found making decisions instead of lying on the floor in a puddle of confusion.

Heuristics are rules of thumb, or mental shortcuts that allow us to make decisions quickly and without much work (1), thus helping us avoid puddled floor-lying. These decision rules are often helpful, but they can also lead to overconfidence.

There are quite a few heuristics, but today I’ll focus on one. The availability heuristic (2) relies on how easy it is to bring to mind information about the current decision, and helps us make a probability judgment about the likelihood of a certain event, in this case, how likely it is that I’ll enjoy the movie.

So, I asked myself if I typically like JD movies and the first Pirates of the Caribbean movie immediately popped in to my head. Because that one example popped in to my head without having to search for it, I am likely to assume that there are many more examples that I could easily bring to mind. Thus, I must really like Johnny Depp movies.

Problem solved — conclusion reached — blog post over (just kidding, obviously).

Here’s a pie chart with my actual JD movie stats.


What can we take from this chart?

·      I’m clearly not that interested in Johnny Depp movies overall.

·      If I take the plunge and decide to watch it, I will have just over a 50/50 chance of enjoying the movie.

·      But, since I still have not decided, we consider the total number of JD movies, which means that I have about an 18% chance of liking it.

My initially high level of confidence is not supported by the data.

What could I have done to reduce my overconfidence?

         Brainstorm JD movies that I didn’t like. Our natural impulse is to look for information that supports an existing idea. Taking the time to look for information that contradicts us is a very important step in critical thinking.

Where else can you use this?

         To examine stereotypes. Just because it may be easy for you to bring to mind examples that make you think that your stereotypes are true, it does not mean that they are. Use your critical thinking skills to re-examine old beliefs and make more accurate judgments about yourself, the world, and other people.

I’m picky about movies, so I want higher odds that I will enjoy them. I will not be watching The Lone Ranger. (I’m sorry Johnny Depp, because I know that you’re reading this… You have lots of other movies that I like, such as Chocolat, Don Juan Demarco, and some of the ones in which you’re a pirate).



1. Kruglanski, A. W. & Sleeth-Keppler, D. (2007). The principles of social judgement. In A. W. Kruglanski & E. T. Higgens (Eds). Social Psychology: Handbook of Basic Principles. (pp. 116-137). New York: The Guilford Press.

2. Tversky, A., & Kahneman, D. (1973). Availability: A heuristic for judging frequency and probability. Cognitive Psychology, 5, 207-232.


AuthorTara Giller