Field of Science

Blood donations: religious and non-religious are equally generous

According to a new analysis of data from the US National Survey of Family Growth, there is no relationship between giving blood any facet of religiosity. Neither the religion in which the person was raised (versus none), nor religious service attendance, nor the importance of religion in daily life, were related to whether the person had given blood in the past.

In terms of raw numbers, women raised as mainline protestants were slightly more likely to have given blood than people from other religions or none (see figure), but these effects disappeared once the statistics were adjusted for other factors (for example, people who are born in the USA are more likely to give blood than are immigrants). There was no effect among men, even in the unadjusted data.

By cutting and dicing the statistics, the authors (Frank Gillum at Howard University and Kevin Masters at Syracuse) were able to find occasional groups that seemed to be more generous donors (Catholic men aged 35-44, for example), but I think they have fallen foul of the problem of multiple comparisons. If you make enough groups (nearly 50 in this case) some are going to come out high just by random chance.

This is a surprising result, given that the religious are supposed to be more charitable and pro-social than the non-religious. If nothing else, you would expect religious service attenders to donate more, simply because (in the US at least) conscientious and dutiful people are expected to do both.

The authors think that it might be because religiously-motivated charity is primarily directed to people of the same 'tribe'. The problem with blood donations is that anyone could benefit - even people who are outsiders.

That would certainly fit with other research into charitable giving (some 80% of evangelical charitable giving goes to other evangelicals), and charitable giving to co-religious is inversely related to support for broad-based state welfare. It also fits with theories that explain religion as an invented (or socially evolved) tool to increase group solidarity.

But I can't help thinking that another process might also be at work here. One of the interesting things about religion is that, although religious people tend to report that they are more pro-social, when tested in controlled conditions they are not (except when previously primed with religious messages).

Now, blood donations are all traceable. That means you might think twice to make sure that you give an accurate report of your donation history, and resist the temptation to inflate your contributions to match your self image!

ResearchBlogging.orgGillum RF, & Masters KS (2010). Religiousness and blood donation: findings from a national survey. Journal of health psychology, 15 (2), 163-72 PMID: 20207660

Creative Commons License This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.


  1. How to operationalize the statement "Religious people are more generous than others"? This is difficult because moral judgments are not objective(if anything is). Did the study tell what kind of action is generous according to religious people?

    There are many factors which may prohibit religious people to act generously in some particular action. These factors may not have anything to do with religion. For example working-hours, sickness, family(hurry) etc..
    Even antireligious campaigns may make them feel unwanted and make them withdraw from public life.

    Tribe-like behavior is normal to all people, so it would be interesting to know how religious and anti-religious people define generosity.

    Which actions in common society cannot be defined as tools to increase group solidarity? I think economics, advertising, material welfare, food production, culture: theatre, movies, TV, meals etc... can all be seen as tools for group solidarity. So how much this explains just religion? Even smoking cigarettes or drinking alcohol can be solidarity for the group..

  2. Jehova Witness's won't be taking advantage of any blood donations any time soon. They'd rather die than to take a blood donation. Another way religion hurts people.

  3. @alias Edmund: by generous I mean altruistic acts, but you are right that the devil is in the detail. For example, if a rich person votes for a political party that favours taxing the rich, then does that count as a generous act?

    From an evolutionary perspective, many anthropologists have proposed that religion came about as a way to increase pro-social behaviour and so increase the success of the group. There are, of course, lots of other ways to do that (tattoos, uniforms - even marching in step and singing). Religion provides a way to bind this together and give them ritual, sacred meaning.

  4. If nothing else, you would expect religious service attenders to donate more, simply because (in the US at least) conscientious and dutiful people are expected to do both.

    Not everyone can give blood. Though it's easy to assume that a blood donation is as easy to give as a monetary donation, that is certainly not the case.


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