Deductive Reasoning Pages Jason Buatte and Kathy Rey

Introduction to Deductive Reasoning Thinking Deductive Reasoning vs. Decision Making

Deductive Reasoning and Cognitive Development Jean Piaget Jean Piaget’s theory states there are basically four levels of cognitive development.  Sensori-Motor : birth to age 2  Pre-Operationa l: age 2 – age 6  Concrete Operational: age 6 – age 12  Formal Operational: age 12 – adulthood

Concrete Operations and Deductive Reasoning The third and fourth stages of Piaget’s model are the most related to deductive reasoning. Stage 3 (Concrete Operations) – logical reasoning replaces intuitive thought. Stage 4 (Formal Operations) – children are now able to hypothesize, and think about the future and what they can be as well as what direction they can go.

Deductive Reasoning Conditional Reasoning  Also referred to as propositional reasoning.

Conditional Reasoning Propositional Calculus Categorizing the kind of reasoning Antecedent – statement/proposition that comes first (the “if” statement).  Affirm Antecedent  Deny Antecedent

Conditional Reasoning Propositional Calculus Categorizing the kind of reasoning Consequent – proposition that follows; the consequence (the “then” statement).  Affirm Consequent  Deny Consequent

Syllogisms Three statements: Two we assume are true, and one conclusion. View this link: A1KH8 A1KH8

Difficulties with Negative Information People handle positive information better than negative information People have trouble processing sentences with negative words (i.e. not, no, never)

Abstract Reasoning Problems People do better with examples that are concrete vs. abstract.

Belief-Bias Effect Making judgments based on prior beliefs and general knowledge This rule is not absolute Republicans vs. Democrats Do you think that everyone should vote a certain way, or do you think it is their choice?

Belief - Bias and Semantic Knowledge Example: A friend of mine had a student in 2 nd grade. She was teaching that police officers are good and keep us safe. A student raised her hand and started crying. She said she was very afraid of police officers and that police officers are bad. Why? The only encounter that this student had with police officers was when they came and hauled her father off to jail.

Schemas are impacted by Belief - Bias As in the previous example, the little girl’s schema and script about law enforcement officials is now and probably will always be, negative. She saw the police beat down her door and have to use force to take her daddy away. She was scared and upset, therefore, she now looks at police in a negative light.

Confirmation Bias Effect People would rather confirm something is true rather than disprove it. If this is an apple, then this is a fruit.

Confirmation Bias and Long Term / Semantic Memory The Confirmation Bias has a direct impact on our Long Term Memory as well as our Semantic Memory. Decisions that we make are influenced by our semantic knowledge. Our semantic knowledge and long term memory is in direct correlation with our biases and beliefs.

Confirmation Bias and Feature Comparison Models The Feature Comparison theory states that people store concepts in their memory according to a list of necessary features. People use a decision process to make judgments about these concepts. Example: True or False….Baseball is a sport.

Confirmation Bias Experiments Wason Selection Task Selection.shtml Selection.shtml

Our Confirmation Bias Experiment We hypothesized that teenagers might disprove this theory because of their rebellious nature. Many teens are interested in proving something wrong. First you get to try…then we will reveal our results!

Directions Follow these directions on the following slide: On the back of the cards with a sport, there is a gender. On the back of the cards with a gender, there is a sport. Choose one card that you would flip to see if the following statement is true.

If a student plays soccer, that student is a girl. Which would you flip? SoccerBoy Volleyball Girl

Directions Follow these directions on the following slide: On the back of the cards with a grade level, there is a sport. On the back of the cards with a sport, there is a grade level. Choose one card that you would flip to see if the following statement is true.

If a student plays football, that student is a senior. Which would you flip? SeniorJunior Volleyball Football

Directions Follow these directions on the following slide: On the back of the cards with an age, there is a school club. On the back of the cards with a school club, there is an age. Choose one card that you would flip to see if the following statement is true.

If a student is a member of student council, that student is over 15. Which would you flip? 15 years17 years Student Council Member Spanish Club Member

How did you do? If you chose soccer, football and student council, you have proven the Confirmation Bias to be correct. If you chose girl, senior or 15 years, you were trying to disprove this statement.

Our Results We were wrong! We surveyed 75 students grades % Confirmed the first statement 52% Confirmed the second statement 56% Confirmed the third statement

Summary Given a hypothesis, people try to confirm rather than disprove. Negative statements require deeper thinking. Concrete examples are easier than abstract examples to solve. Prior knowledge and experiences influence reasoning.

References Madruga, J. A. G., Moreno, S., Carriedo, N., Gutiérrez, F. (2000). Deductive Reasoning and Strategies. Mahwah, New Jersey: Lawrence Erlbaum Associates. Matlin, Margaret W. (2005). Cognition. Danvers, MA: Wiley and Sons. Plucker, J. A. (Ed.). (2003). Human intelligence: Historical influences, current controversies, teaching resources. Retrieved [October 30, 2008], from ftp://ftp.prenhall.com/pub/esm/web_marketing/GagliostrS/a shcraft/ch11.doc