Judgement, Decisions, and Reasoning Flashcards
What is reasoning
The process of drawing conclusions.
Cognitive process of starting with information and coming to conclusions that go beyond that information.
Deductive reasoning
Sequence of statements called syllogisms, used to reach a logical conclusion.
Inductive reasoning
Arrive at conclusions that are probably true.
Premises are based on observations and we generalise from these cases to more general conclusions with varying degrees of certainty.
Syllogism
Logical argument in which we deduce a conclusion on the basis of two other statements (premises).
Categorical and conditional syllogisms.
Categorical syllogisms
Describe a relationship using the words all, no or some.
Premise 1: all cog students are enrolled at UC
Premise 2: all students are UC have an id number
Conclusion: all cog students have an id number
Valid when the conclusion follows logically from two valid premises.
Validity
A syllogism is valid when the form of the syllogism indicates it’s conclusion follows logically from its two premises.
Not necessarily true.
Invalid syllogisms
Invalid when conclusion does not follow logically from two valid premises.
All of the students are tired. (All A are B)
Some tired people are irritable. (Some C are D)
Some of the students are irritable. (Some A are D)
Belief bias
The tendency to think a syllogism is valid if it’s conclusion is believable.
Mental model
A specific situation represented in a person’s mind that can be used to help determine the validity of syllogisms in deductive reasoning.
Mental model approach
Create a model of a situation.
Generate tentative conclusions about model.
Look for exceptions to falsify model.
Determine validity of syllogism.
Conditional syllogisms
Have 2 premises and a conclusion like categorical syllogisms, but the first premise has the form ‘If… then’.
Antecedent: the ‘if’ term (often called the ‘p’ term)
Consequent: the ‘then’ term (often called the ‘q’ term)
(See pg 391)
Syllogism 1: modus ponens
Affirming the antecedent
If I studied, I’ll get a good grade. I studied. Therefore, I’ll get a good grade. Second premise: p, conclusion: therefore, q. Valid: yes.
Syllogism 2: modus tollens
Denying the consequent
If I studied, then I’ll get a good grade.
I didn’t get a good grade.
Therefore, I didn’t study.
Second premise: not q, conclusion: therefore, not p.
Valid: yes.
Syllogism 3
Affirming the consequence
If I studied, I’ll get a good grade. I got a good grade. Therefore, I studied. Second premise: q, conclusion: therefore, p. Valid: no.
Syllogism 4
Denying the antecedent
If I studied, then I’ll get a good grade.
I didn’t study.
Therefore, I didn’t get a good grade.
Second premise: not q, conclusion: therefore, not q.
Valid: no.
Atmosphere effect
Words all, some, no create a mood or atmosphere that affects judgements to a conclusion.
Falsification principle
To test a rule, you must look for situations that falsify the rule (rather than satisfy it).
Trying to break the rule to prove it’s correct. If you can break it, then the rule must be true.
Watson’s four-card problem.
Permission scheme
States that if a person satisfies a specific condition (being of legal drinking age), then they get to carry out an action (being served alcohol).
Evolutionary perspective on cognition
We can trace many properties of our minds to the evolutionary principle of natural selection.
Social-exchange theory
States that an important aspect of human behaviour is the ability for two people to cooperate in a way that is beneficial to both people.
Problems arise when someone cheats.
So detecting cheating has become part of the brain’s cognitive make up to better chances of survival.
What affects strength of an inductive argument?
Representativeness of observations (how well do the observations about a particular category represent all the members of that category?)
Number of observations (more observations, more likely to be correct)
Quality of the evidence (stronger evidence results in stronger conclusions).
Why use inductive reasoning?
Science: for hypothesise and general conclusions.
Everyday life: make a prediction about what will happen based on observation about what has happened in the past.
Heuristics
Rules of thumb.
Availability heuristic
States that events that are more easily remembered are judged as being more probable than events that are less easily remembered.
Representativeness heuristic
States that the probability that A is a member of class B can be determined by how well A resembles properties of B. Eg pick one US man who wears glasses, is quiet and reads a lot. More likely he’s a librarian or farmer?
Conjunction rule
States that the probability of a conjunction of two events (A and B) cannot be higher than the probability of the single constituents (A alone or B alone).
Confirmation bias
We selectively look for information that conforms to our hypotheses and we overlook information that contradicts them.
Expected utility theory
People are rational and if they have all the relevant information, they will make a decision that results in the maximum expected utility.
Don’t always do this though eg gambling.
Influence of emotions on decision making: expected emotions
Emotions that people predict they will feel for a particular outcome.
Incidental emotions
Emotions that are not caused by having to make a decision.
Can be related to a person’s general disposition.
Opt-in, opt-out
Opt-in: person takes the initiative and takes active steps to become an organ donor.
Opt-out: person is an organ donor unless they request not to be a donor.
Risk-aversion strategy
When choices are framed in terms of gains, people are encouraged to take the choice which avoids risk.
Risk-taking strategy
When choices are framed in terms of losses, people are more likely to engage in risk-taking strategy.
Framing effect
Decisions are influenced by how a decision is stated (can highlight one aspect).
