“…Parents’ education level was used as an index of socioeconomic status (e.g., see Ex and Janssens 1998; Finkelstein et al 2007). Participants separately indicated their mother’s and father’s highest level of education as follows: 1 = elementary school , 2 = some high school , 3 = high school graduate , 4 = some college , 5 = bachelor’s degree , 6 = some graduate school , or 7 = graduate degree (master’s, doctorate, medical, law, etc . )…”