The lights are going off in Europe. In Greece, it's called "operation thermostat". In Holland, the motto is "zet de knop om" - turn down the knob.

The goal is to save energy. Gas prices in Europe have hit an all-time high. Next month, UK bills will be almost triple last winter. Money expert Martin Lewis warns, "people will die this winter," unable to heat their homes.

The UK government insists energy use is a "decision for individuals," and they will not force people to unplug. However, chancellor of the ExchequerThe chancellor of the Exchequer, often just called the chancellor, is the UK government's chief finance minister. They are in charge of taxation and government spending and borrowing. Nadhim Zahawi said last Friday, "we should all look at our energy consumption".

According to research, UK households can follow energy-saving tips to cut their gas bill by 31%.

Gently persuading people to make better choices is the idea behind behavioural economics - using psychology to understand decision-making. Governments have embraced the theory, setting up nudge unitsThe first was set up by the UK government in 2010 and is called the Behavioural Insights Team. Since then, over 200 institutions globally have applied behavioural insights to public policy. and employing psychologists to develop policies.

Some say nudge theory is even worse than useless.

Supporters say the power of the nudge is enormous. For example, if you have to opt-in to organ donation, only about 30% do. In countries where you must actively opt-out, 85-90% are automatically enrolled. A simple nudge makes organ donation the norm.

Other techniques include simplifying choices, applying social pressure¹, displaying health warnings, and offering reminders².

A nudge campaign to persuade everyone to turn down their thermostat from 20C to 18C would save 14% on gas bills. Shorter showers with a low-flow shower head could cut another 4%. Households could shave off a further 3-6% by turning the heating off in September and March.

A recent review found "no evidence" that nudging worked. Its effect is no greater than a placeboPatients may report feeling better after taking treatments with no medical value. This is called the placebo effect. In order to distinguish between perceived and actual effects of a new treatment, researchers will test a placebo or "sham" alongside the real treatment - and compare the results. or statistical noiseUnexplained variations in real-life experiments.. Supporters have cherry-picked successful projects.

Scientists Nick Chater and George Loewenstein once believed nudges could solve social problems. But they now doubt its power.

One energy boss predicts that half of UK households will be in fuel povertyWhen a household spends more than 10% of their income on heating or is unable to afford to adequately heat their home. by January. So many are demanding radical action instead of energy-saving tips.

Half a million have signed up to the campaign Enough is Enough³, demanding price cuts. The package may cost £100bn a year. Over 100,000 have pledged to stop paying their bills altogether on 1 October.

Yes: Behavioural economics shows us that if millions of people change their habits it can have an enormous impact on society. And change is infectious - the more we see it, the more we want to change too.

No: It is easy for governments to tell individuals to use less energy. But when families cannot afford to heat their homes through the winter, they need financial help, not tips and tricks.

Or... In reality, we need to change the system and individual behaviour - at the same time. In a fair society, everyone behaves responsibly and there is support for those who need it.