Similarly, the massive wave of emulation (copycat) suicides after a widely publicized suicide is known as the Werther effect, following Johann Wolfgang von Goethe's novel The Sorrows of Young Werther. The novel, in which the hero kills himself, was banned in some European countries after its publication more than 200 years ago because of a rash of suicides by young men who had read it.

While copycat suicides are not as common as feared, the existence of suicide clusters has been confirmed by studies launched by the Center for Disease Control and Prevention in Atlanta, Georgia, in the US.

But knowing that publication of anti-social events such as mass stabbings, airport bombings or celebrity suicides, compounds the problem, begs the question as to how the media should handle such events. Should the media turn a blind eye or attempt to put a positive spin on bad news?

There is a strong psychological argument why media should temper the reporting of negative events. "Negativity bias" is the phenomenon by which humans pay more attention to and give more weight to negative rather than positive experiences or other kinds of information.

Roy F. Baumeister, a professor of social psychology at Florida State University, co-authored the idea of the negativity bias in a literature review in 2001 entitled, "Bad is stronger than good". This review went through a whole gamut of psychological contexts from first impressions, close relationships, memory, self-identity and more, where a negative bias was apparent.

Baumeister and his co-authors provide fascinating and very convincing evidence from different fields of studies and research that people perceive negative experiences much more intensely than positive experiences. The effect of these negative experiences also seems to have a greater impact and to last longer than the effect of positive ones.

There is, however, a countervailing argument as to why the media must report negative events. It is, quite simply, that transparency builds trust. Psychology aside, if people believe that the media are hiding unpleasant truths or attempting to sugarcoat them, people will be less inclined to believe the media.

The media's job is not to psychologically filter out facts to make press reports more palatable, but to determine what facts are most important for the public to know.

In the final analysis, although psychology may suggest reasons we should not hear or read about negative events, knowing that we are being told the truth is the greatest service the media can provide.

The author taught psychology for many years and is a fellow at the Institute for Analytic Journalism.