Self-effacing bias is a trait commonly found in collectivist cultures (cultures in which the group is viewed as more important than the individual). (hyperlink with collectivism )
This trait is widely seen in Asian cultures such as Chinese and Japanese societies. In this type of cultural setting, an individuals are expected to subsume and absorb themselves into the group culture. Success in a venture is ascribed to external factors (luck, group effort, etc.)and failure is blamed on internal factors caused by the individual (lack of sufficient effort, bad luck, etc.). Self-effacing bias is the opposite concept of the self-serving bias in which success is attributed to internal reasons (I am smart, I am talented) whereas negative events are ascribed to external factors (The test was too hard, the teacher hates me).