Religious prejudice

I attended some talks at an international conference on science and religious conflict. What surprised me was the lack of scientific rigour in studies of this subject.
I was less interested in conflicts with a religious nature and more interested in religious conflict with science, and whether religion leads to conflict. The theologians and philosophers can talk all they like about religious doctrine, but what matters is the feeling of religiosity in the believers.
Religiosity is an accepted term in this field, it seems, but is hard to measure. It's easy to get weighed down by academic disagreements over pet theories about whether religious feeling can be divided into different classes (questing religion, for example, hardly follows the Western concept of a religion having unquestionable doctrine at all).
I would be happy with questionnaires about how often a person attends divine worship combined with a linear scale of religious fervour on which a participant must mark a cross.
The biggest problem with the research about religion and prejudice is the definition of prejudice, a point made by a philosopher (Ingmar Persson), but in a rambling and extensive way, in which he concluded that all opinion could be prejudice.
I agree with him to an extent, that the work has not identified prejudice well, but I wouldn't be so kind as to suggest that this is because prejudice is a vague, indefinable term. Measuring the effect of religious sentiment on an individual example of prejudice gives no meaningful results (despite the authors' conclusions). The study of which I am thinking concluded that religion can both create and dissipate prejudice, as was made clear in the different attitudes of religious respondents to homosexuality and Muslims.
This sort of conclusion is almost a truism. If something in which one deeply believes tells you that certain desires are sinful, you will be prejudiced against those with such desires.
What we really need to know is whether religion increases the general (or average) level of prejudice, if we can imagine such a thing. In animals the equivalent would be the level of defensive posture in response to strangers. In humans it is harder to conceive of an unbiased indicator because in-group and out-group sentiments are more complex, and so a 'stranger' might not necessarily be regarded as fully 'out-group', thereby destroying the usefulness of any experiments trying to measure attitudes towards out-groups.
If some behavioural measure could be used, without the volunteers' direct knowledge, that would truly tell us something about how religion influences people.
In order to find such a behavioural measure, we would need to assess how religion affects people's perceptions of who is 'in-group' and who is 'out-group'. Only then can we accurately provide each participant with behavioural cues that allow us to determine his responses to each type of category.

The other aspect of the study was the use of mortality salience testing, in which people were reminded of their mortality in order to make them more uncomfortable. Mortality and existential dread affect all humans, and religion certainly offers one way of coping with these inevitable aspects of intelligence. Hence religious people were less fazed by mortality salience.
An interesting counterpoint would be to examine whether religious people could be fazed (and therefore have their behaviour negatively affected) by other cues that do not affect atheists. For example, many scientific discoveries and theories directly contradict religious doctrines. Where atheists might be comfortable with such knowledge, religious people might be uncomfortable because the source of their comfort in situations including mortality salience is undermined.
The use of false comforts and the psychological conflict between knowledge and comfort therefore helps retard the progress of science.

This issue is now returning to previous, more philosophical, musings on this subject. It is the human need for comfort and familiarity, and the subordination of reason to emotions (such as this happiness with comfort, certainty, false purpose and familiarity) that is the flaw in our species.
Religion gives us purpose and absolute certainty in a world where these things do not truly exist. The need to have bedrocks on which to build our lives ruins our species.
Even in science we cannot do things properly. Instead of probabilities or likelihoods of truth we state a result as absolute truth if the result obtained passes a specific, arbitrary boundary of improbability if the conclusion were false. This arbitrary boundary allows us to state whether a conclusion is, or is not, justified in a binary manner. We should be stating probabilities of truth.
We need to accept the way science builds truth from 'truth density clouds' of results in the same field, just as physicists accept the use of probability density functions for small particles.
Science offers us accuracy, when used correctly, with increasing precision the more we use it. Religion offers us perfect precision but with completely ungovernable accuracy. And we as a species, with remarkable disregard for the truth, choose precision of knowledge over accuracy. We choose comfort over truth, emotion over sense, familiarity over curiosity and stability over progress: we choose religion.

I buck the trend of the species. I love truth. I get a little warm glow inside every time I break apart a puzzle and get the result, be it a puzzle of data, a riddle of life or analysing the foundations of a moral or political assertion. My certainty in life comes from the joy of applying logic and rigour; it comes from the truths I have so far uncovered (given the data I have) and the certainty that although the details of knowledge might change with new data, the beliefs I hold at any moment in time are the closest that I can get to the truth at that time.

As the Bible itself (almost) claims:

Magna est veritas et praevalebit
Great is truth and it shall prevail (a bit)
(I prefer the misquotation and mistranslation to the real version)