Let’s say you are following your dream to kick your day job and start a pizza joint. Many consequential decisions need to be made, but one that will certainly affect your production and display process will be the shape of the pizza: round or square? You might have personal preferences, but how will your customers see it? Given the same size, which shape will be seen as a better deal? Questions on package shapes often arise for consumer goods, but while pizza is ubiquitous, its shape has not been systematically investigated until recently. The broad area of inquiry is called psychophysical biases in area comparisons and three researchers considered the shape problem to figure out what a pizza parlor should do.
People have trouble comparing areas of objects. Comparing single dimensional figures such as two lines is easy. When a second dimension is involved leading to shapes such as triangles, squares and rectangles, area comparisons come into play to determine which shape is larger. The common tendency is to underestimate the importance of one of the dimensions, usually the less prominent one.
Consider what happens when an elongated rectangle and a square (both of equal area) are compared. The first dimension that people are drawn to, as it is more salient, is the elongated side of the rectangle which is quite obviously longer than the corresponding side on the square. But because people like to simplify things they don’t pay as much attention to the second dimension (where the square appears to be only somewhat larger). This results in most people incorrectly concluding that the rectangle is larger.
The problem becomes harder when circles are involved given their unique shape. The researchers ran several experiments to understand how people make area comparisons. Some of these (non-pizza) experiments showed that people use the first (salient) dimension as a primary point of comparison and later adjust this to incorporate the second dimension. Since the adjustment is often wanting, the comparisons are not very accurate. When contextual information (such as diagonals and shading) is provided, peoples responses tended to vary (but did not necessarily become more accurate). This suggested ways by which a pizza company could more advantageously position its pies.
In the first pizza experiment, the researchers tested area comparisons of round and square pizzas (of the same size). In one case the diagonal of the square pizza was made more salient by displaying it in a diamond pattern (i.e. with an edge facing down), while in another case the side was facing down in a conventional display. The results showed that people estimated the square to be larger when placed in a diamond pattern and the circle to be larger when placed in a regular square pattern. Moreover they were also willing to pay more for the square pizza displayed as a diamond, even though in reality they were going to get the same quantity with the round pizza. Clearly a pizza house would be better off if it followed this display strategy.
In the second pizza experiment, the researchers considered how “small”, “medium” and “large” sizes should be labeled. As with existing practice should sizes be given by diameter dimensions (8 inches, 10 inches etc), should the actual area of the pie be provided, or should sample pies be displayed? The results showed that people were willing to pay more when size was expressed as an area instead of the conventional diameter description. They were also willing to pay more when a sample pie was displayed rather than just the diameter to explain the size. Lastly, the pizza parlor was better off selling two small pizzas instead of a large one (i.e. using a buy one get one free strategy, instead of discounting a large pizza).
Those are all strategies that a pizza parlor could use to its advantage. What if you just want to buy pizza, not sell it? If you see a round and square pie next to each other look carefully, don’t assume the square is larger. If they look similar, check how many slices there are in each. It’s quite likely the round will have 8 slices while the square will have either 9 or 12 slices. If buying by the slice go for the round. If your favorite topping is not available in round, then I’m afraid you’re on your own.
This research was conducted by Robert Krider, Professor of Marketing at Simon Fraser University, Priya Raghubir, Professor of Marketing at New York University and Aradhna Krishna, Professor Marketing at the University of Michigan. Their research was published in Marketing Science.