A U.S. study found that cellphone use is linked to selfish behavior and may make users less socially minded, researchers said. Marketing researchers at the University of Maryland conducted a series of experiments involving test groups of cellphone users. They found after a short period of cellphone use subjects were less inclined to volunteer for a community service activity when asked, compared with a counterpart control group, a university release said Tuesday. The cellphone users were also less persistent in solving word problems even when told their answers would translate to a monetary donation to charity, the researchers said. They said previous studies suggest an explanation of their findings. \"The cellphone directly evokes feelings of connectivity to others, thereby fulfilling the basic human need to belong,\" resulting in reducing one\'s desire to connect with others or to engage in empathic and prosocial behavior, they said. Although the study involved college student subjects, both men and women generally in their early 20s, researchers said the results were likely to be universal. \"We would expect a similar pattern of effects with people from other age groups,\" researcher Rosellina Ferraro said. \"Given the increasing pervasiveness of cellphones, it does have the potential to have broad social implications.\"