“…Social and urban studies generally include basic socio-demographic variables, such as gender, age, race, income, job, and education, as control variables [ 40 , 41 , 42 , 43 ]. However, among these, variables other than gender and education (i.e., age, race, income, and job) did not need to be included in the control variables, because all participants were Korean university students in their 20s, and therefore such control variables were not relevant.…”