 |
 |
 |
Failures in human reasoning are the bane of court cases, science, and human relationships. Princeton psychologist Philip Johnson-Laird proposes a new theory for how reasoning takes place – and why it sometimes fails. His theory of mental models developed with Ruth Byrne many colleagues, and outlined in his review, “Mental Models and Deduction,” published in Trends in Cognitive Science (October 2001), postulates that when people reason, they think about the possibilities compatible with the premises and with their general knowledge. (For more details, see the mental models webpage: www.tcd.ie/Psychology/Ruth_Byrne/mental_models/.) This theory departs from the standard view, which assumes that there is a formal logic in the mind. “Formal rules of inference play no part in inferences,” says Johnson-Laird, “though from Piaget onwards, psychologists have proposed theories based on them.” His theory is bolstered by several lines of evidence. For example, individuals have difficulty in reasoning when the premises are compatible with many possibilities. Such inferences take them longer and are more likely to lead to error. The theory also postulates that models of possibilities represent only what it true. An unforeseen consequence is that people can easily succumb to fallacious conclusions. Consider this problem as an example: Either Ann is sitting on the sofa and watching TV or else Eve is standing at the window and watching the birds. Ann is sitting on the sofa. Is she watching TV? Most people say, "yes." But this is fallacious. Suppose Eve is standing at the window. Then Ann can be sitting on the sofa provided that she is NOT watching TV. In other words, we all fail to think about the different ways in which the first scenario can be false given the truth of the second scenario. “Such fallacies are hard to explain
on the assumption that the mind is equipped
|
 |
|
 |
|||
