Criminals are deploying “psychological tactics” to con people out of cash amid a rise in scams, Barclays bank says.

The tricks include creating illusions of product scarcity or pretending to be an authority to “socially engineer” victims, the bank’s chief behavioural scientist Dr Pete Brooks warned.

He said scammers used dating apps to target people over weeks in some cases to establish “emotional connections”.

Dr Brooks added they preyed on people’s biases and personality traits.

He told the BBC although the types of scams hadn’t changed over decades, criminals were becoming more sophisticated and could use “many more channels” to target people.

Using dating apps as an example, Dr Brooks said scammers would connect with people they matched with, develop a relationship over time, and then exploit people’s personality traits to get them to transfer them money.

“Most of us by default are trusting,” said Dr Brooks.

Dr Brooks said so-called “purchase scams”, where goods bought online don’t exist or never arrive, were the most common type.

He said such crimes involved fraudsters creating a “perceived scarcity and therefore ‘value’ in what they are selling to motivate consumers to act quickly and not rely on their better judgment”.

This might be advertising something as a one-time offer, he added, or a product with a limited-edition price or availability, or “rushing us into buying something that ‘has’ to be bought now – even if you’ve never seen the product in real life”.

Barclays said the average amount a person loses through purchase scams totalled £980; however, research found scams targeting people investing led to the most money being lost.

Figures showed a 17% rise in all reported scams in the last three months, while attempts at conning people increased by 70% in the final three months of 2021.

Impersonation scams, Dr Brooks said, involved criminals exploiting a trait found in more than two-thirds of Brits surveyed, as being more likely to comply with a request if they believed it to be from a well-known institution, such as a bank, the police or the NHS.

“In these situations, scammers will harness that sense of authority to instil fear in their victims,” he said.

“Perhaps suggesting their bank account has been compromised, they are overdue a payment or that they will be fined if they do not pay the full amount. Psychologically, many of us will take these at face-value if they’re coming from what we believe to be a reputable institution.”

Meanwhile, investment scams, Barclays said, saw a victim lose on average £15,788 the last three months of 2021.

Dr Brooks said scammers were “experts at exploiting the fact people want to grow their assets, and that we can sometimes put our better judgement aside for a high return opportunity”.

Barclays said that was reflected in its research, with three in 10 people admitting they would be willing to go with an investment or savings provider they’d never heard of if they thought the returns would be higher than their existing provider.

Barclays said real phone calls from a bank will never ask customers to share their pin number or security information or to transfer money to a “safe account”.

The bank said its advice was “always to question whether something appears too good to be true, and not to be afraid to be suspicious”.

But it warned “worryingly”, almost a third of 2,002 people it polled admitted they “wouldn’t know what to do if they found themselves being targeted”.

If you, or someone you know, have been affected by fraud, help and support is available from Action Fraud and at BBC Action Line.