Scientists at Finland’s Aalto University School of Science and Technology have studied the cellphone use habits of 5.3 million people over a period of 18 months, and discovered that prepaid users tend to be stingy both when it comes to making calls and returning them. The study says, “Postpaid users tend to be more prolific, having on average 5.41 people they call. Prepaid users, by contrast, have only 3.41 contacts on average (although the notion of “average” is a little strange here since there is a very long tail on these distributions).” Take a look at the published graph below.
The study further showed that postpaid users made about 10 times as many calls as their prepaid counterparts, which could be explained by the fact that the prepaid service is more popular among the youth. But it could also be the result of special offers by cellphone companies. These results were arrived at by a study of reciprocity, which has implications for the study of how things spread in a society, from human ideas to biological viruses.