There's a fascinating talk
here called "Love, Belief and Neurobiology of Attachment" on the role of oxytocin in trust relationships. You can skip the first 3 minutes of introduction and the final 15 minutes of questions, but the remaining half an hour is well worth watching. The most interesting bit was on the 2% of subjects who just don't react at all - and also share traits of being emotionally labile, happy to gain from the loss of others, and view the world of being made up of trusting people (i.e. mugs). But it's all worth a look - keep your finger on the pause button though - the slides don't appear for nearly long enough to take in all the detail.
What I also find fascinating is that the person is giving the talk to a Christian Bioethics Research Centre, and has clearly tailored bits of his talk to them. I had to ignore the occasional thing in the talk, but the bits of how trust links in to belief was quite interesting all by itself.
Over
here is a similar piece on mother-child interactions, which picks back up one of the things mentioned in the talk - that while there are genetic predispositions for oxytocin receptiveness, it's incredibly affected by the treatment in the early weeks sof life.
(cheers to
is_not_well for pointing me at the talk in the first place).