The difference between 'truth' and 'belief' is determined by, at what point of our query we run out of answers. Since there is no predetermined metric for the number of questions that should be asked, it is up to us, as to when we give up asking questions and ascribe everything else to god or whatever we prefer.
As our knowledge is processed into intelligence, we increase our capabilities to ask more questions. For example, someone intelligent about the stock market will be able to comprehend an event better than the average, because this person will be able to answer a lot more questions in terms of 'truths'.
I'm not sure if this 'number of questions' can be related to other professional characteristics of a person, but at what point we will stop looking for the truth and resort to 'belief' is to a large extent determined by the effects of social forces on an individual? Searching for the truth is however an individual trait?
As individuals we look to discover the 'truths' and as a society we try to 'believe'?