This open the doors to the need of introducing the dark side of power (also called abusive supervision). The literature is characterised by a lack of a cohesive definition about the dark side of power. Instead, the literature focuses on particular characteristics or themes of dark side behaviours and traits. Ashforth (1994) argued that leaders who frequently engage in a range of behaviours including: self-aggrandisement; belittling of followers; lack of consideration for others; forcing style of conflict resolution; punishment for no apparent reason and discouraging initiative, undermine organisational goals and the well-being of followers.
In a recent study, Schilling (2009) founded that these leaders also exhibited behaviours that were aimed at obtaining personal rather than organisational goals. Similarly, Higgs (2009) founded four themes relating to dark side behaviours including abuse of power; inflicting damage on others, over exercise of control and rule breaking to satisfy personal needs. Leaders exhibiting these behaviours are perceived as untrustworthy, overly ambitious and disingenuous by followers (Hogan, 1994). Leaders may exhibit the dark side of leadership due to a range of factors: A leader may move from being constructive to destructive due to situational factors or personality traits. It can derive from a lack of self – esteem which is translated in aggressiveness and violence with the intent to dominate the others, or at the opposite it can be caused by an excess of self – esteem and self – love which makes the leader unable to accept critics or others’ ideas. The dark side of power can also be associated with personality disorders such as narcissism, psychopathy, Machiavellianism, failure of vision, corruption of charisma, lack of emotional and socio-political intelligence or non-leadership.
The last reason is suggested by the aggression literature, which asserts that individuals engage in aggressive behaviours in part as a result of learning from role models in a social setting. Accordingly, when leaders experience abuses by their own leaders, they tend to feel it is appropriate and acceptable to display abusive behaviours toward their subordinates and thus engage in this practice frequently. A social learning theory contention is that the degree to which people emulate the acting of their role models depends on three factors: retention; reproduction and motivation. After having analyzed the main characteristics of the abusive supervision it is possible to address it among the unethical kind of leaderships. This statement is proved not only because abusive supervision has been cited among the variety of unethical leader acts, but also because the definition of unethical leadership itself :” behaviours conducted and decisions made by organizational leaders that are illegal and/or violate moral standards, and those that impose processes and structures that promote unethical conduct by followers” perfectly matches with the previous description of abusive supervision.