Opinion: from social situations to seeking to cause harm to others, there are many reasons why people resort to fibbing

By Lisa O'Rourke-Scott, Limerick Institute of Technology

Why do people lie? To gain personal advantage, to cover up wrongdoing, to win popularity and gain social advancement, to cause harm to others. They lie to avoid shame. They also lie to maintain relationships and promote harmony.

When people deliberately tell untruths, there can be clues that we notice either consciously or unconsciously. They may touch their faces more often than usual or avoid eye contact. But it can be difficult to measure. 

A popular solution to knowing truth from lies, much beloved by certain TV shows, is the lie detector or polygraph. These machines purport to identify lies by measuring heart-rate, skin resistance and respiration. However, the evidence for their effectiveness is poor. The only time they might work is if people think they do! 

From RTÉ Radio One's Ray D'Arcy Show, an interview with former Oklahoma detective Doug Williams who decided to expose the lie detector industry and coach people in how to pass a polygraph test

Consideration of the psychology of lying shows why these machines can’t work. What they are essentially attempting to do is to measure stress levels, but what stresses people varies. Some people are not stressed by lying at all. Others, such as those who spread malicious gossip, may enjoy repeating the stories that they tell and even believe them when they are telling them. 

But the biggest problem with trying to scientifically identify lying is that people lie in social situations all the time. This is why when psychologists attempt to study lying in the laboratory, they immediately have to exclude a whole series of known lies from analysis.

From RTÉ Archives, Newsround visits Blackwater, Co Wexford in 1975 to report on its competition for the biggest liar in Ireland

For example, "I’m well, thank you" in response to an inquiry after one’s well-being is often a lie that we don’t count as a lie. It’s even the opening reply we give when we consult our doctor. The reason we don’t count it is that there is a culturally shared understanding that the person who made the inquiry doesn’t really want to know the answer. So the difference between truth and lies is blurred.

Some lies are necessary to ease the wheels of social interaction. People may request brutal honesty, but they rarely really want it. Most of us learn early in life what things may and may not say and in what contexts. The points at which these quite subtle and sophisticated rules have not been learned often make for hilarious anecdotes about children’s faux pas and indiscreet utterances. 

People may request brutal honesty, but they rarely really want it

Another problem with trying to identify lying is that of perspective. People perceive and understand the world in different ways. It may be that people sincerely believe that they are telling the truth when they say something which is not factually accurate. Recent studies of students in higher education, for example, suggest that there are a variety of understandings about what sexual consent means. In this context, it is entirely plausible that a person may have raped someone and not believe that it was rape at all. 

The ability to lie is something that emerges as a function of psychological development. Central to this ability is what psychologists call "the theory of others’ minds": the ability to predict what information other people have access to. According to psychologist Jean Piaget, children experience the world in an "egocentric" fashion in early infancy. Egocentrism refers to a way of thinking in which a person is unable to understand that their knowledge or perspective may differ from others.

Where would your favourite soap be without some lies?

As development progresses, most children by the age of four can understand that different information is available to different people. As a species that has relied on living collaboratively, having a theory of others’ minds is undoubtedly extremely useful. In order to work together effectively, we all need to be psychologists of some kind. We need to be able to "fill in the blanks" for someone who is missing vital information about a situation and we need to be able to avoid causing offence or damaging relationships by saying things which might cause harm.

There is another reason why lies and the ability to lie to ourselves in particular are useful psychologically. In his 1890 book The Principles of Psychology, William James suggested that if people are having a bad day, they should go around smiling at people. Obviously this is not helpful advice for someone with profound clinical depression, but for cheering up an ordinarily miserable day it has been found to be very effective.

There have also been studies which suggest that those who are clinically depressed often have a more realistic and accurate understanding of the world. It appears that the price of happiness is actually a level of self-delusion to help us cope with the unpalatable realities of life.

Lying, it seems, is integral to the human condition. It is not possible to separate the lies that we find morally reprehensible from those that we find beneficial or even necessary. The truth (if I may use that term) is that our inability to fully know what others are thinking is what makes human interaction so very interesting.

Dr Lisa O'Rourke-Scott is Programme Director on the BA in social care work and lectures in psychology on this programme at the Limerick Institute of Technology. She has been an Associate Lecturer in psychology with the Open University since 2003. 

The views expressed here are those of the author and do not represent or reflect the views of RTÉ