The Power of Graphs

A couple days ago I had students present their physics lab reports to the class. They did a good job, but I think I need to emphasize the importance of including graphs in their results. It’s much harder to look for trends and patterns in the data without charts, especially when presenting to an audience.

An interesting political science study (via Yglesias) found that it’s much easier to change people’s minds when you show them graphs, even when people don’t want to believe what you’re telling them.

[P]eople cling to false beliefs in part because giving them up would threaten their sense of self. Graphical corrections are … found to successfully reduce incorrect beliefs among potentially resistant subjects and to perform better than an equivalent textual correction.

–Nyhan and Reifler (2011): Opening the Political Mind? The effects of self-affirmation and graphical information on factual misperceptions

Despite the fact that the number of jobs increased in the last year (according to the Bureau of Labor Statistics), many people who disapprove of President Obama believe that the economy lost jobs. A lot of people who were told this with text still believed that there was a net job loss, but when presented with a graph of the actual data the number decreases to close to zero. (Graph from Nyhan and Reifler (2011)

Teachers know how hard it can be to correct misconceptions – people tend to stick with the first thing they learned – so it’s good to see that graphical corrections can make a big difference.

Fortunately, my physics students are changing over to math next week, so we’ll be able to use their experimental data to draw lines, find gradients and do all sorts of interesting things.

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