When asked, students said they spent an average of 149 minutes *per day* on Facebook, but monitoring software found that this was a gross overestimation.
People are notoriously unreliable sources of information about their own habits. One study, performed in 2003, found that 50 percent -- 50 percent!! -- of self-reported non-smokers being treated for head and neck cancer "were in fact smoking actively," their lie revealed when scientists looked at their breath and blood for chemical clues.
But nevertheless, researchers often have to rely on self-reporting -- whether the question at hand is health habits or social-media use. And when it comes to the latter, people are apparently no more reliable than they are on questions of the former. A new study reports (pdf) found that college students estimated that they spent 149 minutes *per day* on Facebook, but when monitoring software was installed on their computers, the data revealed a much smaller number: just 26 minutes.
Reynol Junco, a scholar with Harvard's Berkman Center, says that the students in the study did have a pretty good sense of their relative Facebook use: Students who were heavier users estimated higher; those who were lighter users suggested as much. But ALL were wildly off when it came to the absolute estimate. (Though the number of students participating in the study was quite small -- just 45 -- Junco says the effect was so huge that the result is nevertheless reliable.)