Oshio's study is the only recent investigation attempting to
link these bad habits with the Five Factor personality traits of Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness.
As Oshio concluded,“there may be both neurophysiological and social
norm processes controlling nail-biting behavior in males, while social norms are a stronger controlling factor than neurophysiological processes in female nail-biters.”.
Because the key behavioral
variables were not normally distributed, Oshio tested the personality-repetitive behavior relationship by comparing
those who never engaged in the behavior with those who scored 2 or higher, indicating that they did engage in these behaviors.
Why people engage in these behaviors despite the health risks and
violations of social norms becomes the next question, and according to Oshio they occur as a coping mechanism for stress,
as an unconscious behavior that people physiologically can't inhibit, or that the people engaging in them aren't aware of the fact that the behaviors violate those social norms.