Tali Sharot, a neuroscientist at University College London and senior author, said: “Whether it’s evading tax, infidelity, doping in sports, making up data in science or financial fraud, deceivers often recall how small acts of dishonesty snowballed over time and they suddenly found themselves committing quite large crimes.”

Sharot and colleagues suspected that this phenomenon was due to changes in the brain’s response to lying, rather than simply being a case of one lie necessitating another to maintain a story.

In the study, published on Monday in the journal Nature Neuroscience, 80 volunteers played a game in which they estimated the value of pennies in a jar and sent their guess to an unseen partner. Sometimes participants were told they would secretly benefit at their partner’s expense if they overestimated the cash in the jar, incentivising them to lie.

Neil Garrett, also of UCL and a co-author, said: “We knew by how many British pounds they lied on each trial. The amount by which participants lied got larger and larger.”