Some people feel so "creeped out" that they would prefer not to receive an organ or blood that came from a murderer or thief, according to researchers who assessed people's beliefs that a transplant would cause the recipient's personality or behavior to become similar to the donor's.
"Even though science doesn't support the possibility, people still believe that transplants can result in personality changes," said Sarah-Jane Leslie, a professor of philosophy at Princeton University and one of the study's co-authors.
The lead author of the study was Meredith Meyer, a research fellow in psychology at the University of Michigan. Other members of the research team were Susan Gelman and Sarah Stilwell of Michigan. The findings were recently published in the journal Cognitive Science.
Leslie said the idea for the study came from a conversation she had with her collaborators at Michigan about author Sir Arthur Conan Doyle's "The Adventure of the Creeping Man."
In the story, said Leslie, Sherlock Holmes investigates a famous professor's increasingly mysterious behavior. "The professor has become aggressive, proficient at climbing; his knuckles have thickened, and so on. Holmes figures out that in order to stay youthful, the professor — who is, as it turns out, is seeing a much younger woman — has been injecting himself with a serum derived from monkeys. As a result, the professor has taken on the characteristics of the monkeys.
"This seemed to us a vivid fictional illustration of essentialist thinking: the belief that a serum — or blood, or an organ — transferred from one individual to another could cause the recipient to become more like the donor," Leslie said.
Psychological essentialism, Leslie explained, "is the idea that, from a very young age, people believe that there's something deep within us — an essence — that causes our outward features and behaviors. The inclination to think in essentialist terms is very powerful and doesn't depend on learned, scientific knowledge," she said.
The Michigan study presented an opportunity to explore essentialism in adults.
"Even with no scientific evidence to support the idea that a heart transplant or blood transfusion could make you become more like the donor,” Leslie said, the study results "suggest that, despite the absence of scientific support, there's a persistent belief that individuals' internal parts have causal powers, and so — if they are mixed — can make a recipient take on some of the donor's characteristics."
According to the study results, recipients prefer to get an organ or DNA transplant or blood transfusion from a donor whose personality or behavior matches theirs, said Meyer. People think that the behaviors and personalities of others are partly due to something hidden deep inside their blood or bodily organs, she said.
What surprised the research team was that perceptions of the personality changes stemming from blood transfusions were just as strong as those regarding heart transplants.
"Since blood transfusions are so common and relatively straightforward, we had expected people might think that they have very little effect," Meyer said.
According to Leslie, the study's 696 participants included roughly equal numbers of men and women from the United States and India. Overall, American and Indian participants gave largely similar patterns of responses, with individuals in both countries expressing the belief that these transplants could lead to personality changes. Belief in this possibility was found in these two populations, despite the two countries having quite different histories with organ transplants, and despite notable religious and cultural differences.
The participants viewed a list of possible human donors and judged whether they wanted someone who shared similar traits, such as age, gender, sexual orientation and background. Possible donors also included two animals: a pig or a chimpanzee. For human donors described as having the same gender, the characteristics could be positive (e.g., high IQ, talented artist, kind person or philanthropist) or negative (e.g., low IQ, thief, gambler or murderer).
Respondents ranked how much they liked the idea of each of the possibilities being a donor. Questions also involved thoughts about feeling "creeped out" or "contaminated" by the transplant.
"Donors of the same gender, background and sexual orientation were preferred over all others," Leslie said. "When considering human donors, participants were particularly uncomfortable with the idea of receiving a transplant from an individual whom they regarded as morally repugnant (e.g., a murderer), or who was in a negative life situation (e.g., a homeless person)," she said. "Social evaluation played a significant role in people's assessment of transplants, and the strongest preference was for the donor to be just like the recipient."
Transplants from animals were judged to be particularly distasteful. The belief that a recipient might take on some of the donor's characteristics is interesting when it comes to the possibility of transplanting organs from other animals to humans, said Leslie.
"From the medical point of view, this is beginning to look like a promising way of addressing donor shortages," Leslie said. "But these results indicate that potential recipients could struggle with the belief that accepting such a donation will profoundly change who they are."
The study was funded in part by National Science Foundation grant 059394 to Gelman.