This one could have as easily gone into the Critical Thinking Collection, as it relates to how we understand (or don’t) the information that is presented to us when looking at maps, particularly during the political season. Yonatan Zunger offers some good reminders.
Originally shared by Yonatan Zunger
As election season enters into full swing, we’re going to see more maps in the news and on social media. So this is a good time to remind ourselves of one of the most important ways maps lie: by making some things look bigger than others. Some things to watch out for:
(1) Land area isn’t the same as people! In the map below, those dark spots account for a full 50% of the population of the US. If you see a traditionally-shaped map of the country, or of a state, shaded by who’s leading where, it will look like the preferences of the most rural voters drastically dominate. When those disagree with the preferences of urban voters – as they often do, it’s a very basic kind of split – the map could make it look like urban voters “stole” the election, since “obviously” more people favor the rural side. Watch out for these!
(2) Color can fool the eye. The human eye is designed to react very strongly to some colors (e.g. red, the color of blood), and far more weakly to other colors. If a map is pure red and blue, for example, the red areas will look more prominent visually. If a map shows shades of purple, though, purple will look more like blue (because we’re not as sensitive to it), and so blue will look artificially prominent instead!
Ultimately, maps fool the eye. There are things like “cartograms,” maps which are stretched out so that the area shown is proportional to something of interest, like the number of people, and other color schemes which account for the eye’s sensitivity better. (Check out this site for examples using the 2012 election: http://www-personal.umich.edu/~mejn/election/2012/)
These fix the problems above, but the result looks so little like a traditional map that their value as actual geography goes away. The “best” 2012 map, in the sense of accounting for those issues, reveals mostly that Republican support is strongest in a sort of “web” centered in the middle of the country and with holes corresponding to most of the cities, while Democratic support is in the cities and on the coast. But at this point, it’s fair to wonder if there would have been a better way to show that – e.g., with a two-dimensional chart, showing population density on one axis and percent results on the other, with one dot shown for every precinct.
The main lesson from this is to take any political maps you see with a tremendous grain of salt. Whenever you’re in doubt about their meaning, look for a chart instead; the numbers will be more honest.
h/t Amber Yust.