1. Deduction biases and content effects bias = whenever there is a systematic deviation in performance from the normative approach

2. Belief Bias make conclusions based on personal beliefs about the world (you are supposed to use logical rules to draw conclusions) Selma Hayek looks best sporting the “uni- brow” that she had in “Frida” Ben Affleck and Jennifer Lopez will have a longlasting marriage

3. Validity of the silly statement sometimes being logical, means providing reasons for your conclusions Women look their best when sporting a “unibrow” The actress that played “Frida” sported a unibrow Selma Hayek is the actress that played “Frida” Selma Hayek looked best sporting the “unibrow” that she had in “Frida”

4. Laboratory evidence Believable conclusions = are consistent with your personal beliefs Unbelievable conclusions = are inconsistent with your personal beliefs (e.g., unibrow statement) also, valid and invalid conclusions believable/valid, believable/invalid, unbelievable/valid, unbelievable/invalid

5. Results Evans, Newstead, & Byrne (1993) % of conclusions accepted as valid Valid Invalid Believable 86% 66% Unbelievable 62% 13% conclusion: the believability of a statement has a strong influence on people’s critical thinking (i.e., belief-bias effect)

6. content effects def.: whenever the “content” (i.e., the specific words) influences your critical thinking performance normative approach  content is irrelevant and should not influence your performance

7. Wason selection task Manchester Leeds Train Car (imagine that these are four cards, each having a city on one side and a mode of transportation on the other) “Every time I go to Manchester I travel by train” answer: turn over Manchester and Car

8. results in laboratory Wason & Shapiro (1971) showed that students did a good job with this version of the task compared to an abstract version conclusion  adding realistic words (content) to an abstract problem improved performance (thus, it’s a content effect)

9. guaranteed solution to the selection task (algorithm) D B 3 5 7 If a card has a D on one side, then it has a 3 on the other side. answer: D, 5, 7 p not p q not q not q If p, then q answer: p, not q

10. Test 1 Study Guide normative approach, descriptive approach logic, def. of rational logic vs. real-life syllogisms, deduction, parts of the syllogism, validity of conclusion, algorithm, Euler’s circles conditional reasoning problems, conditional, content of a problem vs. logical structure

11. Test 1 (cont.) logical rules related to conditional reasoning, affirming the antecedent, etc. (including modus ponens, modus tollens) Wason selection task, abstract vs. realistic content of a problem logical operators, if…then, and, or, not; two types of “or” (exclusive, inclusive) disjunctive reasoning; deontic content or deontic reasoning

12. Test 1 (cont.) bias, belief-bias, personal beliefs vs. logic, content effects