According to this theory, logically-untrained individuals reason by using the meaning of assertions to construct mental models of the situations that they describe. A conclusion is logically necessary if it holds in all the models of the premises. Dr. Fabien Savary , who is now a Web maestro, and I have confirmed their existence. Here is an example. If there isn't a king in the hand, then there is an ace in the hand.
Subjects overwhelmingly infer that there is an ace in the hand.
This phenomenon is predicted by the model theory, which postulates that reasoners normally represent only what is true, and not what is false, in their models of the premises. Notice, however, that if the first assertion is false then there is a king in the hand, but not an ace. And if the second assertion is false then there isn't a king in the hand and there isn't an ace in the hand. Hence, either way, there isn't an ace in the hand. Current theories of reasoning based on formal rules of inference, because they contain only valid rules of inference cannot explain such a systematic error.