EVERYONE has something at their core - something they believe in, or, something they have FAITH in. it might not necessarily be a god or a transcendent being - it might be themselves, or a CONCEPT, or it might just be a sense that there’s something more, or a sense that there’s nothing at all. at the very center of every person is that one thing the mind flies to in moments of danger or death or trouble or hopelessness - there’s that one thing the mind clings to in moments of complete joy and peace. those feelings and emotions are grounded in that thing, and often it’s the thing that people will pray to - even without realizing it. 

     now, prayer doesn’t necessarily mean getting down on your knees and folding your hands and reciting certain words in certain ways. it can be that, but it can also be a quick exclamation, a fleeting hope that materializes in an unspoken thought. 

     as far as RIVER goes, the thing at her core is her FAMILY. it’s something she always wanted when she was a child, and once she finds it, something she clings to. in moments when she thinks her life might end, or she might lose something of inestimable importance, her thoughts automatically go to the people she loves ( amy, rory, the doctor ). i think that, in a way, she prays to them. i’m not saying she worships them, but i think that it could be argued that she does worship the concept of family. she’d do anything, say anything, be anything for them. so it’s logical that in moments of distress she’d either call upon them or the memory of them for help.