Researchers say the current "honesty test" used in courts should be reviewed after finding big differences in what is judged to be a dishonest act.
A survey of 15,000 people in England and Wales suggested a wide variation in views of what was honest or not - particularly for petty acts.
Just 47% thought that it was wrong for a carer to persuade a patient to change their will in their favour.
The current test - the Ghosh test - assumes a universal view of honesty.
The Brunel University study also found that women were more likely to find activities such as taking stationery home from work dishonest, but less willing to convict the wrongdoer than men.
The researchers, who are criminal lawyers, say that their early findings suggest the Ghosh test - which assumes a universal view of what constitutes dishonesty and is used in court cases - should be reassessed.
The findings are due to be presented at the start of the British Science Festival at the University of Surrey in Guildford.
The web-based "Honesty Lab" study, launched in May by the two Brunel criminologists in conjunction with the British Science Association, asked participants to watch five video clips in which morally questionable behaviour was dramatised.
They were then asked if they thought the actions were dishonest or worthy of conviction in a court of law.
In total, 40,000 scenarios were viewed, attracting one million hits to the web site.
The researchers say the results raise serious questions about people's concepts of honesty and the reliability of the jury system.
The study found that 88.5% women believed buying a dress for a special occasion and then returning it to the store and getting a refund was dishonest.
Broccoli stalks
But just 46.7% took the same view of a care home nurse persuading an elderly patient to change a will in her favour.
A large majority of men had a similar attitude, with 82.6% thinking it was morally wrong to "borrow" the dress but only 37.6% disapproving of taking advantage of someone who was elderly and infirm.
The findings suggested that if a jury of 12 men and women was asked to pass a verdict on the care home nurse, only four would want to convict.
A higher proportion of women, 82.2%, thought it was dishonest to lie about age on an internet dating site than believed it was wrong to benefit from the will alteration.
In a league table of dishonest acts, conning the elderly care home patient came 13th out of 16 - just one place above snapping off broccoli stalks in a supermarket and weighing the heads.
The two actions considered the most dishonest were buying goods online using a colleague's shopping account and setting fire to a garage to make an insurance claim.
The Ghosh test asks if an action was dishonest according to the "ordinary standards of reasonable and honest people".
But researcher Dr Emily Finch said: "We have some scenarios that are exactly the same in terms of the legal issue that they involve, but we have seen a massive difference in reaction to them.
"It seems to be based on whether or not the person speaking is likeable.
"When we like people or feel sorry for them, we are far less likely to condemn what they have done so this has a major effect on whether or not their conduct is rated as honest or dishonest."
A majority of people don't think exploiting the infirm is dishonest. OMG.
frigidmagi wrote:Playing Devil's Advocate here so please no lynch mobs.
In this case the person doing the exploiting is the person who does the most to care for them. Is it wrong for them to benefit from that?
Whoops. Sorry, totally missed your response.
I'd say "yes, it is wrong", since then the help which is offered by the person is not offered in good faith. If the person wants to benefit from the deal, this should be done in an open and honest manner.
