This paper investigates whether ideological indoctrination by living in a communist regime relates to low economic performance in a market economy. We recruit North Korean refugees and measure their implicit bias against South Korea by using the Implicit Association Test. Conducting double auction and bilateral bargaining market experiments, we find that North Korean refugees with a larger bias against the capitalistic society have lower expectations about their earning potential, exhibit trading behavior with lower target profits, and earn less profits. These associations are robust to conditioning on correlates of preferences, human capital, and assimilation experiences.