Educational activity among adults is not only a key factor of social development but also one of the most important priorities of public policies. Although large sums have been earmarked and numerous actions undertaken to encourage adult learning, many people remain educationally passive, a particularly acute problem in Poland. We point to the main cultural and economic determinants of educational passivity: the family environment, education, low earnings and job. Based on several years of research conducted within the Study of Human Capital in Poland project, we conclude that the Matthew effect is visible in the field of adult learning: better-educated people increase their educational capital, moving further away from those with a lower level of education. Comparison of the levels of self-evaluation of competences between educationally active and non-active adults of various levels of education indicates that the highest increase in evaluation occurs among less educated people. Owing to this group's very low level of education, however, the scale of using the potential for educational activity is very low. The outcome of this is that the opportunities created by adult educational activity are not exploited to reduce social differences and instead it sometimes reinforces these differences.