empirical study on the subject reveals the differences in attachment styles across regions and ethnicities as well as associations between cultural identity and attachment.. for en-cashing these relationship etethnocentricstaffing policy is preferred at the executive level for global operations in a multinational organization. following link may be more useful concerning to this.
It depends on the assignment purpose and host country specifics. For a more detailed account see Harzing, A. W. (2001). Who's in charge? An empirical study of executive staffing practices in foreign subsidiaries. Human Resource Management, 40(2), 139-158.
I believe it is based on cultural norms, specific national laws and the staffing practices of the original nation of the multinational as well as the culture and background and diversity at the executive level. Cultural environment has a profound effect on social behaviours; Moreover, as another scholar pointed out here, attachment theory as it applies to culture may be a factor. I believe further empirical study would benefit, using your question as your research question.