Most teachers would discourage children from enacting any of the seven deadly sins, and with good reason: they are not usually useful when creating a productive classroom environment. But neurobiologist and writer Jack Lewis urges teachers to think again: he says it’s healthy for children to commit one of the seven deadly sins from time to time, as it can provide a boost for mental and physical wellbeing.

Lewis reached this conclusion while researching his recently published book The Science of Sin: why we do the things we know we shouldn’t. In each of the book’s chapters, Lewis tackles one of the seven deadly sins, which are also known as “capital vices” or “cardinal sins”: he provides the historical background to it, looks at how to resist it and then explains why we all tend to succumb to pride, greed, lust, envy, gluttony, wrath and sloth, from time to time.

Lewis says he had been ruminating upon writing such a book for some time.

“I am an evidence-based human. That’s why I became a scientist,” he explains. “But when I make moral judgements, science has nothing to say to guide me really. I don’t believe in God, but I don’t think we should throw away everything that is written in religious books. So I thought it would be an interesting project to look at the neuroscience that touches on those seven subjects.”

What he decided was clear was that each of the sins is not necessarily always bad for you; rather that too much of each would lead to trouble. So a little greed or pride is unlikely to be an issue, but too much of each probably will be. And often the problems will come in the form of social isolation, which can be incredibly damaging both physically and mentally.

“‘Deadly sins’ is actually bang on the money, but when that phrase was first coined they couldn’t have possibly known that those behaviours - being anti-social and making people more isolated - would likely end up being bad for their health and literally deadly,” Lewis says. “These isolated people will die earlier than they otherwise would - of things like cancer or cardiovascular disease, because it’s incredibly stressful taking life on solo.”

But in moderation, the deadly sins can actually benefit health, he argues. Take greed and sloth. In order to be a successful, healthy school pupil, you need a bit of both from time to time.

“I think of greed from the perspective of it doesn’t matter how much you’ve got, you always want more,” he explains. “That hyper-competitiveness.”

That can drive a student on to top grades, but only in the short term. In the long term, they need a bit of sloth.

“We all need to spend a little bit of time each day, each week, each year engaging in doing nothing because that gives the body and brain the chance to heal, repair and do the maintenance. If you never give your body and brain the chance to do that, you’re kinda screwed. So a little bit of sloth is good in counterpoint to greed and a little bit of greed is good in counterpoint to just being completely unmotivated to get anything productive done.”

It’s a similar situation with pride. Although it’s good for students to take pride in their work and be proud of their achievements, as this will drive self-efficacy, for example, going too far and being boastful can be incredibly damaging as it is isolating socially and can lead to over-confidence.

And again, with envy: it can be used by teachers as a motivational tool, but it can also be incredibly detrimental to an individual’s wellbeing. “Benign envy is when you compare yourself with other people, you analyse what they’ve been doing and you haven’t, and maybe this will motivate you to do [something] so that you can get the skills they have,” Lewis explains.

“Then you have malicious envy, where your response to the disparity [between you and another person] and the fact that it makes you more aware of your deficiencies, makes you want to level the playing field. An easier way to try and do that is to bring them crashing down from their pedestal.”

Spotting where the line sits between healthy and unhealthy sinning is no easy task for teachers, he says.

“The reason these things are deadly is it is hard to find the line [between what is acceptable and unacceptable behaviour] because everyone has a different take on where that line is,” Lewis argues.

So what might help teachers? First, accepting that a little sinning is OK, or actually desirable, if it is moderated properly.

But then understanding where the sinning may stem from is key. One of the interesting things that Lewis noticed in the neuroscience research that he ploughed through was that when it comes to pride, wrath, envy and greed, one part of the brain “lights up” over and over again.

“This brain area always crops up when a person is experiencing pain, and it doesn’t matter if it is physical pain or emotional pain. It comes from a place of inner turmoil. So when you’ve got an errant kid who is constantly disrupting everything and ruining it for other children in a lesson, more often than not it comes from a place of suffering. So rather than get angry, which would be the natural reaction, you need to resist that temptation to fight fire with fire and convert some of your frustration and irritation into compassion.”

Lewis believes the best approach would be to give the kids who are the worst behaved - the most anti-social - a little bit of extra attention and enquire how things are going at home and ask how are they doing generally.

“Even if they only give you one-word answers and even if they don’t seem to appreciate the extra interest that you’ve taken in them, you’ve still shown an interest in them and their private inner world of experience and that means that you have acknowledged them as a human being rather than just barking instructions at them like ‘stop doing that’,” he says.

Lewis thinks that as well as offering teachers a useful insight into how to treat children to get the best out of them, the seven deadly sins should be actively taught in schools because it will also teach children how to lead better lives.

“I think we might need to rename them because the ‘seven deadly sins’ or ‘capital vices’ comes with a load of religious baggage,” he says. “We could call it ‘seven anti-social tendencies’ or something that rolls off the tongue a bit better.”

The idea here would not be to preach against the sins, but rather to highlight where they are useful, where they might be manageable and where they can be disruptive.

“It’s fine to have the sloth of ‘I can’t be arsed to do my homework tonight’ as long as you wake up early the next morning and do it then instead, but to never bother to do your homework is a bad idea,” says Lewis.

“It’s fine to feel flickers of envy because it helps you realise, ‘Hang on, why are these people around me doing better than I am?’ because that alerts you to the fact that you are slipping behind. So it’s healthy to feel that little spurt of envy every now and then, but if you spend every moment of the day constantly feeling angry and wanting to avenge people who you perceive have been rude to you, then that’s not good.”

So for teachers, could it really be true that you shouldn’t feel guilty if you succumb to gluttony and reach for the biscuit tin, or if sloth gets the better of you and you play a game of Candy Crush rather than get on with all that marking you need to do?

Well, as long as these habits don’t become all-consuming, the scientific evidence suggests that giving into temptation from time to time can actually be good for you.

Simon Creasey is a freelance journalist