110 likes | 342 Views
Induction. Induction. Inductive arguments increase the strength of your belief in some fact Inductive arguments are not truth-preserving What sorts of factors should increase your confidence in some fact?. Justifications. Inductive arguments influence degree of belief
E N D
Induction • Inductive arguments increase the strength of your belief in some fact • Inductive arguments are not truth-preserving • What sorts of factors should increase your confidence in some fact?
Justifications • Inductive arguments influence degree of belief • Must keep track of why we believe certain facts • AI has a field of truth maintenance • Gilbert • Facts are believed to be true by default • They must be specifically marked as false • There is a persistence of false-beliefs • Johnson & Seifert • Information continued to influence people’s beliefs unless they were given a specific reason why it was false.
Coherence • A coherent story makes beliefs stronger • Pennington & Hastie • Story model of jury decision making
Category-based induction • Our category structures help us predict. Bears have glutamate in their brainsHow likely is it that deer have glutamate in their brains? • How can you answer this question? • What if you know nothing about the property? • These are called blank predicates • What if you do have some relevant knowledge?
Induction with blank predicates • When we know nothing about the property, we rely in similarities among categories Stronger Weaker Bears have XHorses have X Bears have XBirds have X Similarity Bears have XBirds have XLizards have X Bears have XHorses have XLizards have X Diversity Bears have XMammals have X Prairie Dogs have XMammals have X Typicality
Similarity and coverage • Why are these effects obtained? • Osherson, Smith, and colleagues • Similarity-coverage model • The more similar the premise categories to the conclusion, the stronger the argument • The better the premise categories cover the category contained by the conclusion, the stronger the argument.
What about non-blank predicates? • Sometimes we know a little bit about the properties • How does that affect induction? • Heit and Rubinstein • Behavioral and morphological properties • Behavioral and morphological similarity Stronger Weaker Dolphins have antifreeze in their blood______________Sharks have antifreeze... Foxes have antifreeze in their blood_____________Sharks have antifreeze... Foxes are good trackersSharks are good trackers Dolphins are good trackersSharks are good trackers
What if you know a lot? • Experts act differently than novices • Similarity becomes far less important • Causal reasoning based on domain knowledge • Premise diversity effects disappear in experts White Pines get Disease XWeeping Willows get Disease XAll Trees get Disease X River Birch get Disease YPaper Birch get Disease YAll Trees get Disease Y • College students prefer argument on left • Consistent with diversity • Tree experts prefer argument on right • Consistent with their causal reasoning.