Roberto Perotti showed that in accordance with the credit market imperfection approach, developed by Galor and Zeira, inequality is associated with lower level of human capital formation (education, experience, apprenticeship) and higher level of fertility, while lower level of human capital is associated with lower levels of economic growth.[1] Princeton economist Roland Benabou's finds that the growth process of Korea and the Philippines "are broadly consistent with the credit-constrained human-capital accumulation hypothesis".[110] In addition, Andrew Berg and Jonathan Ostry[3] suggest that inequality seems to affect growth through human capital accumulation and fertility channels.