Is there another motivation for christian belief?

[Angrboda]

Is the "social" aspect not a fear of not being accepted? Not being part of the herd?

No, it's more primal and basic. Take for example falling in love. We know that this event is correlated with a symphony of hormonal and neurological events, but all we recognize is the fundament--the emotions under these events. In a similar way, the social aspect is made up of various cognitive/neurological events that underlie our being social primates. The feeling of positive stroking we feel when we engage in conversation. The imagining of the complex of another person as possessing a mind, and our inferring things about what the various behaviors tell us about that mind. The cognitive machinery which allows us to impute a "psychology" to the acts of this other body/animal, that they have beliefs and motives just like we do. The ability to 'imagine' what the other might be thinking and why. These are the cognitive gears that mesh together to create our experience as social animals. Does a bear impute motives to the behavior of other bears? I don't know, but the act of imputing motives is a part of the warp and woof of our experience as social creatures that use language.

What is the "truthful reality" or "search for truth"? Sorry, sometimes I can be dense. Is this the "cognitive primitives" being sought out to be a social animal?

That part is disconnected from the more primitive "social animal" aspect. I was simply speaking of our desire to make sense of the world around us. We seem driven to searching out reasons for why the world is the way it is. I think that the theist, no less than the atheist, is considering the evidence before them and trying to construct a coherent story of why the world has that evidence in it. I don't think theists come to belief out of fear, but rather that they just want to make sense of the world and the evidence they have been exposed to. They're seeking the truth as much as an atheist is seeking the truth, and I think that is the primary motivation.