If an image study is to be conducted the first question which arises is why should money be paid for such a study? In other words, what is the value and utility of an image study. A utility is usually defined in accordance with the function of the instrument used. What does the instrument called an image study do? First, it allows us to establish the way in which objective data is translated into subjective perception by the individual in question. Secondly, it allows us, based on the subjective data the individual has, to establish in which way this subjective data is used in the decision making process.