How does a computer predict behavioral patterns?

I was speaking to my father about my idea this morning and he was telling me how he can relate to this in his field, science. He said, "In medical science we do computer modeling. We have a bunch of laboratory data that is associated with a clinical out come. So we collect samples from a statistically significant number of patients usually in the hundreds to thousands and train the computer to learn that a laboratory parameter is associated with a clinical outcome. Then we collect another set of samples usually in ten to hundred thousands and actually do the analysis asking whether that lab parameter is associated with that clinical outcome. You collect enough preliminary preferences through his/her usage and the computer learns his/her preferences. You do this for thousands and thousands of users and you can statistically predict that an individual will select a certain choice. Thus you have come up with a formula for predicting success."

Although this is an interesting concept, collecting enough data so you can predict a future pattern, it is different than my initial concept for foodNOW. foodNOW should already have a "formula" for predicting whether a person would like a restaurant based on his/her comparable choice. Of course this "formula" or technology should by dynamic and take user preferences to improve upon future suggestions.