Two hundred and eighty-nine undergraduate students (39%
males; 61% females) were recruited in spring 2007 from a single
college dormitory at a private university in the New England area of
the United States. Only students using notebook computers were
invited to participate in the study. Because of the notebook
restriction and attrition, 223 undergraduates participated for the
full duration of the study. Institutional Review Board approval was
obtained from the university.