People's subjective tendency: Is there a mathematical model? In our everyday life, people always intentionally or unintentionally value some objects. However, some tend to overvalue the value of objects, while others tend to undervalue them. For some the deviation is big, while for others it is small. 

So I wonder, are there existing research findings related to this? Or is there a mathematical model to model different people's subjective tendencies on how they value objects in daily life?
I think there is a mathematical model for this.
Have a look at Bayes' Theorem. It is also very interesting from a philosophical and psychological point of view.

Here is a link from Stanford Encyclopedia of Philosophy:
http://plato.stanford.edu/entries/bayes-theorem/