People like believing they're above average. Most people feel they're smarter, funnier, and more attractive than the next person. Unfortunately, this same tendency does not exist among young women when comparing body weight.
In a study by psychologist Catherine Sanderson, of Amherst College, college women tend to believe that they exercised less and weighed more than the average person. Her study also found that this misperception increases over time, as college seniors seem much more likely than freshwomen to misjudge the weight and habits of others.
According to Sanderson, the trend goes something like this: "Jane," the average college freshwoman, first arrives at school weighing 130 pounds. When asked, she estimates that other students weigh approximately 130 pounds—and she's right. Years pass, and Jane observes other women eating less, bragging about rigorous exercise regimens, and skipping meals. By her senior year, Jane has put on a few pounds. Weighing in at 135, she estimates that the average female student weighs 125 pounds. This time, she's wrong. The average student weighs what she does—yet Jane doesn't see it.