There is a shortage of donor organs in the UK
Most people have a strong aversion to the idea of receiving a donor organ from a killer, a study suggests.
Those questioned said they would be far happier receiving a transplant from someone with a good moral background, the Cheltenham Science Festival heard.
It follows on from research which found one in three organ transplant patients believe they have taken on some aspects of the donor's personality.
Around 16m people are on the UK organ donor register.
Professor Bruce Hood, a cognitive neuroscientist at the University of Bristol, tested the effects of information about the morals of a potential donor in 20 students who were asked to imagine they needed a life-saving heart transplant.
They were shown pictures of strangers and asked to rate how happy they would be to receive an organ from them.
The students were then shown the photos a second time but told that the person was good or bad.
Negative scores increased dramatically when they were told the donor was a bad person.
When told they were looking at pictures of good people, there was a small increase in positive ratings.
The largest negative effect was for a murderer's heart.
Professor Hood told the conference that he had spoken with patients who believe they have taken on a psychic connection with their organ donors, and even their memories and experiences.
"Some of the psychological changes many patients experience have very good physiological explanations, however according to one survey of transplant patients, approximately one in three attribute this change to taking on psychological characteristics of the donor even though conventional science has generally rejected the idea that such transference is possible."
He added that in one case, a British teenager was forcibly given a heart transplant against her will because she feared that she would be "different with someone else's heart".
"This explains the findings that most people were repulsed by the thought of receiving a transplant from a murderer.
"Essentially they believe they will somehow take on those characteristics of the donor."
Isabel Clarke, an NHS consultant clinical psychologist with an interest in spirituality said the association of ideas can be very powerful.
"There's quite an emotional punch about the heart and receiving someone's heart."
A spokesman for NHS Blood and Transplant said organ donations were done anonymously in the UK so recipients would not know about the personality of the donor.
"We ensure that organs donated for transplant are matched and allocated based on clinical need and criteria including, age, size, blood group and for kidneys, the tissue type.
"Clinical analysis shows that these criteria are most relevant to the successful outcome of a transplant."