Feiler and Kleinbaum designed their study to evaluate the interaction of two key factors in the formation of social networks: extraversion, which correlates with popularity, and homophily, the idea that people with similar levels of extraversion are more likely to become friends. The results showed that network extraversion bias exists. Furthermore, it is more pronounced in the networks of extraverts. "The skew gets really extreme the more extraverted you are," Feiler reported. Apparently the degree of bias uncovered was unexpected. In addition they found that introverts were more likely to form friendships with other introverts. Their networks still displayed the friendship paradox, but to a lesser degree.