Anger, the most attention-arresting of all our emotions, has been prodded and probed by psychologists for decades. When people are asked to identify an angry face amid a smiling crowd, they can typically pick out the malcontent pretty quickly. Performance in the reverse situation - trying to spot the smile among a sea of snarls - is more difficult and people generally take far longer to accomplish such a task.
For evolutionary psychologists, the explanation for this phenomenon is simple: the ability to quickly spot other peoples' anger has survival value. Anger, after all, is very often the precursor to life-threatening acts of aggression.
Anger's links to aggression have justifiably earned it a bad press over the millennia. The earliest surviving complete work devoted to anger (On Anger) is by the Roman philosopher Lucius Annaeus Seneca. Seneca marshals strong arguments against anger, cataloguing some of history's most outrageous outbursts. For instance, he described how, slighted by some minor transgression, an enraged Persian ruler cut off the noses of an entire population, thereafter earning their town the name Rhinocolura (land of the snub-nosed).
For Seneca, anger shared similarities with mental illness and was the most self-destructive of all vices. As a stoic philosopher, he saw anger's roots in our inability to reconcile ourselves with the inevitable frustrations of existence. For Seneca, the remedy lay in modifying our beliefs about how the world is or should be, something today's psychotherapists might call "cognitive restructuring".
Our various religious traditions too have consistently warned against anger. The Prophet Muhammad, for example, famously counselled: "la taghdab, la taghdab, la taghdab" (don't become angry, repeated three times). Similarly within the Roman Catholic tradition, Pope Gregory I (Saint Gregory the Great) included anger among the seven cardinal, or deadly, sins. This status of "cardinal sin" is afforded to vices that are viewed as capable of engendering other sins.
Anger of course, is associated with a host of problem behaviours, or sins, including homicide, domestic violence, child abuse, impulsive divorce and dangerous driving to name a few.
However, despite millennia of good counsel against anger, recent research suggests that it is perceived as becoming increasingly common in contemporary society. The UK's Mental Health Foundation recently undertook a national anger survey, with 64 per cent of the 2,000 respondents either agreeing or strongly agreeing with the statement that "people in general are getting angrier". One third of the respondents reported having a friend or family member who had trouble controlling their anger while one in 10 reported experiencing similar anger-management issues themselves.
Psychologists and therapists have long noted similarities between anger and depression. Some have even advocated that irritability and hostility (classified under anger) should be considered as key symptoms in the diagnosis of Major Depressive Disorder. Perhaps the rise in depression rates in many nations is connected with the perceived rise in the rates of problem anger.
But the difference between anger and sadness stems from the interpretations we give to negative events. Whereas depression, characterised by sadness, is primarily associated with self-blaming interpretations of negative events, anger is associated with interpretations that place the blame on others. For the depressed individual, their glass is half empty because they deserve such treatment. For the chronically angry, however, somebody stole their drink. Similarly, chronic sadness is often associated with unrealistic self-expectations (I should be perfect) while problem anger is associated with unrealistic expectations of other people (they should not make mistakes).
Lots of people seek help for depression; far fewer seek treatment for anger. This makes sense when you consider that with anger, the problem is generally perceived as external to the individual - not their problem. The answer to reducing societal levels of anger lies in greater psychological literacy and in what I like to call cognitive flexibility (the ability to think about situations from multiple perspectives).
Such knowledge and skills could be imparted through an enlightened school curriculum, one that aims to foster self-awareness, compassion and wisdom in addition to job skills and civic responsibility.
Justin Thomas is an associate professor at Zayed University in Abu Dhabi
On Twitter: @jaytee156