While there may be other influences, the online disinhibition effect14 describes several subtle, but powerful underlying factors that contribute to the nature of communication via digital devices. These factors may help explain the sometimes toxic and aggressive nature of online communications.15
First, the anonymity associated with computer-mediated communication may permit people to possess an alternate online identity and essentially hide behind a nonidentifying pseudonym or username. This form of dissociative anonymity allows people to separate from in-person identity and moral agency, thereby freeing them to express hostility and criticism without any effect to the psyche. Similarly, online users may dissociate those at the other end of the communication by subconsciously viewing them merely as avatars or usernames instead of actual persons.
Second, as online communication can be asynchronous, individuals do not have to manage immediate reactions to online conversations and can remove themselves from the repercussions of online discussions, even avoiding ownership for hostile and intimidating comments. Third, even in a completely nonanonymous environment (ie, computerized medical record, e-mail correspondence, blogs), the nature of online communications is such that individuals are physically invisible to others, permitting them to disregard any type of eye contact or physical reaction of the other person(s). A significant portion of traditional face-to-face communications tends to be nonverbal (eg, body language, tone of voice), and without these cues, online conversations lack an essential element of understanding.16
Overt negativity toward others manifested in online communications should not be attributed merely to character flaws. The online disinhibition effect applies to all individuals regardless of ethical and moral character. Even those of high moral judgment and character can subconsciously devolve into a more pernicious state when they psychologically disconnect their words from their actual being. In essence, the subconscious psychological factors associated with the online disinhibition effect negatively impact the likelihood that empathy will be expressed in digital environments. (Source)