PSYC 213 - Chapter 12

PSYC 213 - Chapter 12 - BeerE 4 Soda 7 24K 16 Ch 12 What is...

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7 4 K E 16 24 Soda Beer Ch 12 What is Reasoning? - “The cognitive processes by which people start with information and come to conclusion that go beyond that information” - Reasoning is relevant in other domains of cognition as well” o In perception—perceiving objects involve inference from incomplete information o In long-term memory—our memories of past events are created by a process of construction, also from incomplete info o In language—understanding one part of the story can depend on inferences based on what you know has happened before - 2 types of reasoning: deductive reasoning (involves sequences of statements called syllogisms) vs. Inductive reasoning (when we arrive at conclusions about what is probably true based on evidence) - Decisions: involves making choices between alternatives; involves both deductive and inductive reasoning Deductive reasoning: thinking categorically - A syllogism includes 2 statements called premises , which are followed by a third statement called the conclusion - Categorical syllogism—the premises and conclusion describe the relation between 2 categories by using statements that start with all, no or some o EX: Premise 1: all birds are animals Premise 2: all animals eat food Conclusion: therefore, all birds eat food - Conditional syllogism—use “if. .. then” statements (discussed later) Validity and truth in syllogisms - A syllogism is valid when its conclusion follows logically from its 2 premises as in the example above; it is considered invalid when it does not - Aristotle’s perfect syllogism: Premise 1: all A are B Premise 2: all B are C Conclusion: therefore, all A are C - We can construct valid/invalid syllogisms to test how well people evaluate validity - The syllogism can still be considered logically valid even if 1 or more of the premises aren’t true. This is because validity depends on the form of the syllogism o In everyday life, we consider what is true to be what is valid. o But in syllogisms, validity refers only to the logical progression of the premises and conclusions o Difficulties in separating between validity and truth lead to errors in reasoning How well can people judge validity? - Early philosophers claim that people think logically; errors with validity are made when people were being careless or weren’t paying attention
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- Cognitive psychologists argue that logic isn’t necessarily built into the human mind. Therefore when we make errors, it’s a result of how the mind operates - Syllogism judgement can be determined using: o Evaluation: where subjects are presented with 2 premises and a conclusion, and they are asked to indicate whether the conclusion logically follows the premises o Production: subjects are presented with 2 premises and were asked to indicate what conclusion would logically follow the premises (or that no conclusion can be formed) - The evaluation method: o There are many reasons why people make errors in syllogisms: e.g. the atmosphere effect and the belief bias
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This note was uploaded on 02/13/2011 for the course PSYC 213 taught by Professor Levitin during the Winter '08 term at McGill.

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PSYC 213 - Chapter 12 - BeerE 4 Soda 7 24K 16 Ch 12 What is...

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