If someone asked you to define a lie, could you? On the surface, it seems a simple demand: “The dog ate my homework,” for example, is very unlikely to be true.

And while lying has a deep history, rich in conflicting definitions, one theme recurs: that lying involves a deliberate deception. In what is perhaps the most beautiful, poetic definition - having one thought in the heart and another on the lips - Saint Augustine cemented a key concept in our understanding of lying: knowingly deceiving another human.

As practising teachers, lies are something that we regularly experience in the classroom. From blatantly untrue excuses for not handing in homework, to the more malevolent lies that some children use to desperately excuse themselves from whatever mess they’ve got themselves into, we see a varied range of lies in our daily lives.

But are all lies equal? Is the act of lying inherently bad, or is it the nature of the lie, the extent of the deception and the consequences of the lie that determine the level of immorality?

Philosophical opinion is divided on the issue. Kant argued that lying is always morally wrong. His central argument was that we are all born with an intrinsic worth - a human dignity. He explored the notion that being human means we have the rational power of free choice. He believed we have to respect the power that we, and others, have: the free choice to be ethical.

Kant also believed that, when we lie, we deprive others of their freedom to choose rationally. In short, when we lie to another human being, we harm their human dignity and autonomy. He proposed that there are no conceivable circumstances in which lying is morally acceptable.

If we accept that this is true, do we have to accept that we compromise our human morality when we lie? What if, in lying, we protect another from physical harm? Is the ethical harm the lesser of two evils?

It’s a difficult concept.

Imagine for a moment that a good friend comes to you looking for a place of safety because they’re at risk of harm. The person they’re at risk from asks you where they are - do you tell them? Most people I know would say no, and that the act of the lie is better than the unthinkable consequences to telling the truth.

But this then raises a question: is the ethical harm we may do by lying less important than the real harm that the truth may cause? I’d argue that, in this case, it is. But if we accept that, in some cases, lying is acceptable, how do we define what is and is not acceptable as a lie? Is it that, where our intentions are good, we can lie? How do we separate morally good liars from deliberately deceptive, dishonourable liars, when the act of the lie makes them as bad as each other?

Does it matter?

Really, does it?

As a society, we pride ourselves on truths. We decry fake news. We demand truth. We virtue-signal and take pride in our outward honesty. Yet, find me a human who says they’ve never lied and I’ll show you a liar. It’s an uncomfortable truth, but we all do it. I did it today, in fact. I bet you did, too.

Humans engage in lying far more than we are willing to admit. We even lie about our own lying.

Psychologist Robert S Feldman argues that lying is far more prevalent than we think. He suggests that for every 10 minutes of conversation time, we lie on average two-to-three times. But our motives vary.

You can’t handle the truth

Psychologists have identified a number of common motives. Chief among them are the instinct to preserve our self-esteem, the need to avoid conflict and the desire to manipulate other people to behave in ways that suit us.

It would seem, therefore, that the philosophical debate misses the mark: we don’t worry about the spiritual judgement of our being. Rather, we behave in ways that benefit us as people.

So, if we all lie on a regular basis, how does this relate to how we manage lying in schools? Rather than teaching children that lying is inherently bad, should we instead be acknowledging that lying is something that we all do, and explore the ethics around the lies that we tell?

The capacity to lie is an important developmental milestone. Understanding that the world has different perspectives, that people have different experiences, is crucial for children’s development. They realise that they can present different versions of reality to different people. While generally this is something that has developed by the age of 3, there are some who argue that children begin to behave deceptively from the age of six months.

Lies, therefore, will play a part in all children’s development - and it is something that we see regularly in school. From the lie about who took the pencil, to much wider, malicious lies, teachers see it all. We have made it our job to detect and challenge those lies in schools.

You’d think, wouldn’t you, given the high incidence of our lie observations, of investigating them, of arbitrating them, that we’d be more highly skilled at spotting a liar than the average person. Some of us may even pride ourselves on it - especially when we’re right, and we can evidence a lie in more serious incidents. And yet, research suggests the exact opposite: that despite our extensive experiences, we aren’t actually able to identify lies better than non-teachers.

This came as something of a shock to me. As a pastoral leader, I have developed the belief that I can spot lies. I deal with them so often that my gut-instinct alarm goes off. It worries me, then, that this may not be the case. Am I, in fact, doing more damage to the process by believing my own bias? And, most crucially, where am I going wrong?

A leading study in this area, by social psychologist Marc-André Reinhard, explored whether experienced teachers were better at identifying lies than less-experienced teachers. The study found, surprisingly, that experienced teachers are no more accurate judges of students’ lies than less-experienced teachers. Equally surprising is the fact that this also applies to other professions, such as the police, where lie detection plays a significant role.

The devil’s in the details

One of the key aspects of the findings in the study relates to the misconceptions that plague society regarding how we spot lies. The stereotypes of what a liar looks like, mid-lie, with their avoiding of eye contact and increased bodily movement, tend to be misleading; we can mistakenly use them to judge a non-liar as a liar.

Psychologist Lucy Akehurst found that, in fact, what characterised a liar more accurately would be less logical consistency in the lie: a lie tends to include more superfluous details and spontaneous corrections than a truth.

So what should we be looking for when detecting lies? According to Bella DePaulo, a psychologist who specialises in detecting deceit, we should be alert to less-plausible content, less-logical structures and fewer details than we might find in truths.

DePaulo also explored the physical behaviour of liars and concluded that they did not show more active body, hand, arm or foot movement than non-liars. Experts and laypeople alike strongly rely on non-verbal cues when judging deception - meaning we are judging the wrong thing.

The findings, across all studies, point to the idea that we’d improve our chances of detecting lies by preventing opportunities for students to prepare responses. Teachers should not display any suspicion; instead, we should casually invite students for a chat under a false pretence.

In other words, we approach lies with lies. The irony is not lost on me.

So we’re not very good at spotting lies and, moreover, there is a question over whether universal suppression of lies is a desirable pursuit ethically or practically. To my mind, we need a reality check.

In investigating or punishing lies in school, are we really making much of a difference? Should we instead be exploring the more ethical considerations with children about where lies may be acceptable and where they may not?

Wouldn’t it be more honest to acknowledge the truth about our lying behaviour? By accepting that we all lie, and exploring the circumstances in which lying is right and wrong, are we better preparing students for adulthood? I’m inclined to believe so.

Amy Forrester is an English teacher and director of pastoral care (key stage 4) at Cockermouth School in Cumbria

This article originally appeared in the 2 October 2020 issue under the headline “You’re lying to yourself”