Let's be honest: you are a natural born liar. So am I. Whether we tell little white lies, designed to spare another's feelings, or whopping great pathological fibs, none of us can escape the inherent human tendency for fibbing. The only question is: what kind of liar are you?
Very few people actually enjoy lying. Indeed, "liar" is one of the most damaging insults you can hurl at another person. None of us wants to live or work with liars: they sow mistrust and shatter relationships.
But that doesn't mean we don't tell lies – and often.
So many lies, so little time
Psychologist Bella de Paulo found that, on average, people tell 1.5 untruths a day. And according to a 2002 study by the University of Massachusetts, 60 per cent of adults can't have a ten-minute conversation without telling at least one lie. The researchers also found that two people will tell three lies within 10 minutes of meeting each other.
As the author of a book on how and why we lie, these numbers seem, to me, like a conservative estimate.
Both studies were carried out before the advent of social media. Facebook and Twitter have multiplied our opportunities to tell lies, and made it much easier for them to spread; these days, a lie gets halfway around the world before the truth has even woken up.
Degrees of dishonesty
It is no coincidence that Donald Trump is both a compulsive Twitter user and accused of being a compulsive liar. Yet we cannot blame social media; it merely amplifies our human predisposition to stray from the truth. As Paul Ekman, a psychologist who has studied the facial expressions of liars, says: "Lying is a central characteristic of life."
It is the degree to which we tell lies that separates us. Most of us lie by saying "I'm fine" when we are actually feeling miserable. We lie when we coo, "what a beautiful baby!" while inwardly marvelling at its resemblance to an alien life form.
At one time or another, we have all simulated anger, sadness, or delight to fit with the expectations of others. We have exaggerated our accomplishments during job interviews. Some of us have even said "I love you" when we don't mean it. Just about everyone has faked enthusiasm for somebody else's cooking.
Sound familiar? The uncomfortable truth is that humans lie almost from the moment they are born. Dr Vasudevi Reddy, of the University of Portsmouth's psychology department, found examples of deceptive behaviour among children less than a year old.
She observed a baby girl reaching her arms out to her mother, before backing away at the last second, laughing her head off (I have been the victim of this particular trick, as executed by my daughter).
Nor do we help matters, telling our children that lying is bad and then insisting they look grateful for the soap-on-a-rope Grandma has given them for their birthday.
'Little big lies'
Almost as soon as children learn to talk, they use words to deceive. They start telling the simplest of lies between the ages of two and three, before moving to more sophisticated untruths between three and four. This is not something to be worried about: developmental psychologists regard it as a sign of social intelligence.
For the most part, children and adults tell "little white lies" – fairly harmless everyday fibs designed to spare feelings. These are what keep the wheels of our society turning. The paradox is that society would break down if we couldn't rely on most people to tell the truth, most of the time – yet it would also break down if we only ever told the truth.
There would be fights on street corners. Families would be torn apart. There is good reason to give these little white liars a free pass.
The bad kind
There are other types of liar, however, who we don't forgive so easily. We give a hard time to dissemblers; experts at twisting words, judiciously omitting information, creating ambiguity and crafting deniability. Certain jobs seem to demand this skill: estate agents, lawyers and politicians all rely on it.
The politicians who tell us, truthfully, that we need to make hard choices tend not to be the ones who become popular, whereas the ones who tell us we can have our cake and eat it fare far better with voters.
Even less defensible are compulsive liars, who constantly regale people with stories that plainly aren't true. They have become addicted to self-glorifying fibs because they are deeply insecure. They get a kick purely out of telling a lie. They usually hurt nobody but themselves – unless by happenstance they end up in positions of real power.
When it becomes an obsession
Pathological liars (sometimes called psychopathic liars) are a different breed again; colder and more calculating. They lie with specific, self-serving goals. They can be charming and credible, and wreak great damage on their victims. It is these sorts of liars who regularly grab the headlines; think financial fraudster Bernie Madoff or American con man Frank Abagnale - immortalised by Leonardo DiCaprio in the 2002 film Catch Me If You Can - who posed as a doctor, airline pilot, teacher and lawyer and became infamous in the Sixties for passing bad cheques worth millions of dollars in 26 countries.
White matter matters
A few years ago, neuroscientists carried out a study on the brains of pathological liars. Their subjects came from the books of a temporary employment agencies in Los Angeles, as pathological liars find it difficult to hold down long-term jobs.
The neuroscientists discovered that the brains of pathological liars have more "white matter". The more white matter, the faster a person's stream of thought and the higher their verbal fluency – enhancing their ability for manipulation.
Previous studies had revealed that psychopaths also have low activity in the emotional parts of their brains - and thus little or no empathy for the effect their lies have on others. Pathological liars, in other words, have powerful equipment for fibbing, and no compunction whatsoever about doing so, making them particularly dangerous.
We might all lie, but at least the majority of us have the grace to feel a little bit bad about it, even when it comes from a good place.
So next time you catch yourself telling a tall story or throwaway fib, ask yourself what sort of liar you are. Honestly? The answer might surprise you.
What type of liar are you?
1. Little white liar
The most common liar. Someone who tells fibs in everyday work and social situations to make life easier.
Your lies are: Broadly harmless. You say "Thanks for the lovely present," when you really don't like it.
Rather than outright lies, a dissembler avoids the truth, manipulating information.
Your lies are: To dodge uncomfortable situations, appear more likeable or tell people what they want to hear.
3. Compulsive liar
Compulsive liars can't help themselves; something in them compels them to fib.
Your lies are: Showy and extravagant. You'll even lie about something you know can be easily checked.
4. Pathological liar
They are probably shrewd, inventive and lack empathy, lying to achieve a selfish goal.
Your lies: Will catch up with you in the end.
The Telegraph, London
Know, or are, a liar? Share your thoughts in the comments section below.