In the Tell ';n'; Show method of creating effective presentations, you tell you point, then you show it. So, each point requires some validation, some evidence. Which validation you choose may depend on your audience. Some people want hard data, others want to know what the competition is doing, and still others may want the advice of an expert. A story that conveys a poignant situation may be effective. Sometimes, all you need is an image to show what you';re telling. If you say that the copier you sell fits on a small table, a photograph will suffice.
In medicine, programs have been developed that analyze the disease symptoms, medical history, and laboratory test results of a patient, and then suggest a diagnosis to the physician. The diagnostic program is an example of so_called expert systems_programs designed to perform tasks in specialized areas as a human would. Expert systems take computers a step beyond straightforward programming, being based on a technique called rule_based inference, in which preestablished rule systems are used to process the data. Despite their sophistication, systems still do not approach the complexity of true intelligent thought.