someone happens to win a lot of money at the casino, why would they not be in a commercial (which they are perhaps getting paid to do on top of their gambling winnings)? If it is that easy to win money, we should all go the casino, as it seems everybody is a winner there. Of course, there is some information that is missing. That is, those commercials never show the people who lost their money gambling at that casino. And, in fact, most people have to lose money gambling as it is one way that the casinos make money to stay in business! But by only making available to viewers the people who won money, casinos make available in our minds that they exist just to hand us cash. So naturally, why would we not go there and gamble? Of course, the casinos neglect to make available the reality of gambling for most people.
Another specific application of the availability heuristic is the framing effect, in which people are persuaded by the way information is presented rather than by the value of the information itself (Hardisty, Johnson, & Weber, 2010). Let’s take an example from a food that I tend to eat too much of: potato chips.
Photo 1.5a and 1.5b Are baked chips really better for you?
Let’s look at RUFFLES® Original Potato Chips (hereafter, “Original Ruffles”) and RUFFLES® Oven Baked Original Potato Chips (hereafter, “Baked Ruffles”), made by Frito-Lay® (Purchase, NY). As you might have guessed, Baked Ruffles are baked. The Original Ruffles are fried. So if one type is called “Baked” Ruffles, why not call the other type “Fried” Ruffles to signify how the chips were made? What image does “fried” make available in your mind? It is likely not one of health food. “Baked,” on the other hand, sounds like it might be healthy, so therefore it is included on that package. This is an example of the framing effect. Health-conscious consumers might not buy Original Ruffles because there is no real health value in them. However, by baking the chips instead of frying them, it does reduce the fat content, so this benefit gets advertised on the package. Original Ruffles do not advertise that they were fried on the package because most people perceive fried foods to be unhealthy.
Framing effect: tendency to be persuaded by the way information is presented.
You might be asking at this point whether Baked Ruffles are healthier than Original Ruffles. Let’s look at the nutritional information to see whether that is the case.
In looking at the nutritional labels for each type of Ruffles, indeed, the Baked Ruffles have more than 50% less fat than Original Ruffles. However, the Original Ruffles have more potassium than do Baked Ruffles. Examining the protein, vitamin, and mineral contents of each bag, they are both low on all dimensions. When we look at the data regarding nutritional content of both types of Ruffles, we see that in terms of vitamins and minerals, there is no big health advantage to Baked Ruffles (maybe less of a “health disadvantage”), no matter how healthy an image such a label may create in our minds. If I want to eat something healthy, data suggest eating snacks such as peppers, bananas, and apples.
Photo 1.6a and 1.6b Are baked chips really better for you?
Representativeness heuristic
The availability heuristic is one barrier to using statistical information. There is another heuristic we use that also makes it difficult to use statistical information. To start this discussion, let me to tell you about my cousin Adam. When he was a toddler, he lived in a house with two dogs. So when Adam saw any four-legged, furry creature, he called it “doggie.” One day when we were at a petting zoo, he saw what I, as a teenager, knew was a horse. But to him, it was a “big doggie.” And indeed, dogs and horses do share some outward similarities (e.g., four legs, fur, and a tail). One difference between dogs and horses is that whereas dogs bark, horses neigh.
So when this “big doggie” neighed, Adam looked most perplexed. That sound did not fit in his mental notion of “dog.” He was forced to change his mental picture of what a dog was, and in addition, he needed to create a new, distinct mental category for this creature he had encountered called a “horse.” In this example, Adam was using the representativeness heuristic (Gilovich & Savitsky, 2002). That is, he had created a mental category of “dog” that included all animals with four legs, fur, and a tail.
Representativeness heuristic: judging how likely something or someone is to the typical instance of a mental category that we hold; can lead us to ignore other relevant information.
So what’s the problem that representativeness plays in our thinking? Those mental categories had to come from somewhere, and indeed, they are often correct or else we would stop using them. In Adam’s situation, the sound that the horse made forced him to redefine his mental category of “dog.” This may not be too difficult to do at least in theory. But remember, I want you to be aware of when our thinking goes awry and how such missteps are rooted in statistical thinking.
Photo 1.7 They look similar, don’t they?
Source: ©iStockphoto.com/GlobalP; ©iStockphoto.com/fotojagodka
There are two potentially problematic results of using representativeness that we will discuss. First, the base-rate fallacy is the tendency to ignore information that describes (i.e., represents) most people or situations. Rather, we rely on information that fits a mental category we have formed (Bar-Hillel, 1980). To take a simple example, approximately 90% of the students at my college are from Michigan, Indiana, and Ohio. At first-year orientation this fall, I talked with a tall, athletic-looking, suntanned student who had long blond hair and was wearing a Ron Jon Surf Shop® (Cocoa Beach, FL) T-shirt. Where was he from? California? Florida? Perhaps. But without knowing any additional information, you have a 90% chance of being correct (assuming you say “Michigan,” “Indiana,” or “Ohio”). Even though the description seems to fit someone from California or Florida, those states are sparsely represented in our student body. Thus, there was minimal chance he was from one of those places despite fitting our mental category of “Californian” or “Floridian.” Let’s explore the base-rate fallacy in a little more detail.
Base-rate fallacy: tendency to prefer information derived from one’s experience and ignore information that is representative of most people or situations.
When we started this chapter, I lamented that we as humans often have difficulty thinking statistically. Again, 90% of the student population at my college is from three states. Therefore, the probability of a student being from any of the other 47 states or another country is low. That probability is even lower for any one specific state of those 47. However, in this instance, the only thing I “saw” was that one student I talked with at orientation. He was a sample of the entire student body at my college. The entire study body at my college consists of people primarily from three states. Therefore, even though he fit my mental representation of “Californian” or “Floridian,” the odds are that he was from Michigan, Indiana, or Ohio.
One danger, in terms of statistical thinking, of our everyday experiences is that rarely, if ever, do we have all of the information about a given situation (we are egocentric, remember). Much as we can rarely, if ever, be familiar with everyone in a large group of people, we rely on our personal experiences to draw conclusions about the world. An extension of the base-rate fallacy is the law of small numbers, which is the second potential problem with using representativeness. The law of small numbers holds that results based on a small number of observations are less likely to
