Name calling is abusive or insulting language referred to a person or group, a verbal abuse. This phenomenon is studied by a variety of academic disciplines from anthropology, to child psychology, to politics. It is also studied by rhetoricians, and a variety of other disciplines that study propaganda techniques and their causes and effects. The technique is most frequently employed within political discourse and school systems, in an attempt to negatively impact their opponent.
As a cognitive bias in propaganda 
Name calling is a cognitive bias and a technique to promote propaganda. Propagandists use the name-calling technique to incite fears or arouse positive prejudices with the intent that invoked fear (based on fearmongering tactics) or trust will encourage those that read, see or hear propaganda to construct a negative opinion, in respect to the former, or a positive opinion, with respect to the latter, about a person, group, or set of beliefs or ideas that the propagandist would wish the recipients to believe. The method is intended to provoke conclusions and actions about a matter apart from an impartial examinations of the facts of the matter. When this tactic is used instead of an argument, name-calling is thus a substitute for rational, fact-based arguments against an idea or belief, based upon its own merits, and becomes an argumentum ad hominem.
In politics and public opinion 
Politicians often resort to “name calling” during political campaigns or public events with the intentions of gaining advantage over, or defending themselves from, an opponent or critic.
During the United States' 2012 primary campaign, name-calling seemingly was employed by both political parties and many candidates, but the presidential primary seemed to amplify the phenomenon.
At the same time, in the state of New Jersey, a fiesty governor, Chris Christie, was also accused of name-calling, prompting a New Jersey based university to poll the matter. Consequently, Peter J. Woolley, political scientist and director of the Fairleigh Dickinson University research group, PublicMind, compiled a list of 14 “insults” that had caught the attention of the media and public. The list consisted of the following names: liar, fake, numb-nuts, bully, snob, unpatriotic, hypocrite, dishonest, jerk, ignoramus, corrupt, flip flopper, radical and fascist. Voters were asked whether these names are “always acceptable” or “sometimes acceptable” or “never acceptable.” 
According to PublicMind, “not all names are equal.”
A sizable majority of New Jersey residents (87%) believe politicians should be respectful towards each other and avoid name-calling. Only (10%) of the remaining voters concurred that name-calling is necessary in order for politicians to make a strong point.
At one end of the “never acceptable” range were “dishonest” (23%) and “corrupt” (24%). The public did not consider these names as offensive as others. At the other end, the top two “never acceptable” names; “numbnuts” (84%) and “jerk” (83%) were used by Gov. Christie during a same sex marriage debate in early 2012. Woolley commented: “People really do want civility in political discourse. The problem is that civility doesn’t sell any advertising, and it doesn’t necessarily energize voters. People want a spark.” 
Significant differences were found between men and women. In general, women had a tendency to be less sympathetic about name-calling than men. For a majority of the names, women were more likely than men to declare them “never acceptable”. For example, half of women (52%) said “fake” is never acceptable, but only 29% of men said “fake” is never alright. For other names like “jerk,” 76% of men said it never acceptable compared to 89% of women, while 79% of men said “numb nuts” is never acceptable compared to 89% of women.
Common misconceptions 
Gratuitous verbal abuse or "name-calling" itself is not an argumentum ad hominem or a logical fallacy. The fallacy only occurs if personal attacks are employed in the stead of an argument to devalue an argument by attacking the speaker, not personal insults in the middle of an otherwise sound argument. However, because a statement can be countered by multiple lines of reasoning, any name-calling relating to the mental faculties of the opponent is typically a case of argumentum ad hominem. For example, ad hominem attacks would include saying the opponent is slow-witted, uneducated, too drunk to think clearly, or needs more sleep for correct judgment. "X's argument is invalid because X's analogy is false, there are differences between a republic and a democracy. But then again, X is idiotically ignorant" is gratuitously abusive but is not a fallacy because X's argument is actually addressed directly in the opening statement. "X is idiotically ignorant" is not a fallacy of itself. It is an argument that X doesn't know the difference between a republic and a democracy. But, the implication is that the opponent is too "idiotically ignorant" to think clearly, about anything. An example of a direct ad hominem fallacy would be "X is idiotically ignorant [of politics], so why should we listen to him now?"
"In reality, ad hominem is unrelated to sarcasm or personal abuse. Argumentum ad hominem is the logical fallacy of attempting to undermine a speaker's argument by attacking the speaker instead of addressing the argument. The mere presence of a personal attack does not indicate ad hominem: the attack must be used for the purpose of undermining the argument, or otherwise the logical fallacy isn't there. It is not a logical fallacy to attack someone; the fallacy comes from assuming that a personal attack is also necessarily an attack on that person's arguments."
- Andy McDonald, Lene Palmer. Propaganda Techniques, George Mason University
- FOX News. Politics. (January 28, 2012). GOP candidates run into ad trouble, resort to name-calling in final Florida stretch
- Politico. (January 30, 2012). Chris Christie calls critic "numb-nuts"
- Fairleigh Dickinson University's PublicMind, (March 26, 2012).Hey, Numb Nuts: Not All Names Are Equal. (press release)
- Ad hominem fallacy, Logical Fallacies, Formal and Informal, Independent Individualist.