Chapter 13

judgement

to judge or form an opinion

Reasoning

the process of drawing conclusion

Decision

the process of choosing between alternatives

Inductive reasoning

the process of drawing a general conclusion based on specific observations.

-Premise is stated as observations of specific cases.

-Conclusion is generalized from premise

-Specific cases -> broad principles

-Bottom-up process ( facts or observations -> hypothesis -> theory)

- if the premise is true, the conclusion is probably true

ex: Ex: the temperature in Riverside reaches 100 every summer. Therefore, it will reach 100 in riverside this summer

Deductive reasoning

the process of determining whether a specific conclusion logically follows from general statements.

-Premise is stated as facts or general principles

-Conclusion is drawn from logical rules applied to the premise

-Broad principles -> specific cases

-Top down process (hypothesis -> facts -> conclusion)

-If the premise is true, the conclusion is definitely true

Ex: all men are mortal. Socrates is a man. Therefore, Socrates is mortal.

How is inductive reasoning strengthen by observation properties ?

Premise, Conclusion, Representativeness, number of observations, and quality of evidence.

Premise

observations of specific cases

Conclusion

generalized from premise

Representativeness of observations

how well observations about a particular category represent all members of that category

number of observations

how many observations we made

quality of evidence

observations can be supported with scientific evidence

How is inductive reasoning weakened by our beliefs ?

Confirmation bias, Backfire effect, inductive argument, and myside bias

Confirmation bias

we look for information that supports our opinions and ignore information that refutes it

Backfire effect

our support for a given opinion can be stronger when faced with facts that oppose it

Inductive arguments

are weakened by a bias to confirm (or support) our opinions

Myside Bias

we evaluate evidence in a way that is biased toward our own opinions and attitudes

How is inductive reasoning influenced by availability and representative heuristics ?

Heuristics, Availability heuristics, Illusory correlations, Representativeness heuristics, Base rate, Conjunction rule, and Law of large numbers.

Heuristic's

educated guesses, intuitive judgments, or common sense used to solve a problem quickly

Availability heuristics

events that come to mind more easily are judged as being more probable

-Undue weight is given to anecdotal evidence that comes to mind more easily

-Our conclusions are biased by evidence that is more available

Illusory correlations

when a relationship between two events appears to exist, but, in reality, there is little or no relationship

-Stereotypes are a common form of illusory correlations

Representativeness heuristics

events that are more similar to a given category are more likely to be judged as being part of that category

We rely on representativeness to the occupation categories and ignore the base rate

Base rate

the relative proportion of different classes in the population

Conjunction rule

the probability of a conjunction of two events cannot be higher than the probability of the events alone

Law of large numbers

the more individuals that are randomly drawn from a population, the more representative the group will be of the entire population

how decision making is affected by how the choice is framed ?

Status quo bias, Risk Aversion, Dual system Approach, Decision, Framing effect, : the tendency to do nothing when faced with making a decision

Risk aversion

the tendency to avoid taking risks

status quo bias

the tendency to do nothing when faced with making a decision

Dual system approach

Dual systems approach: idea that we may have different systems for decision making.

- Our decisions can be biased by other, seemingly unrelated factors

Decision

the process of choosing between alternatives

Expected utility theory

assumes if people have all relevant information, they will make a decision that results in outcomes that help to achieve their goals

Framing effects

decisions are influenced by how the choices are stated

Ex- beef: 75% lean, 25 % fat

Condom: 95% success rate, 5 % failure rate

Smoking: living longer if you quit, due sooner if you don't

Purchase: 50 % of two items, buy one get one free

How is deductive reasoning affected by how the choice is framed?

Categorical syllogism, conditional syllogism, valid syllogism, invalid syllogism, belief bias, and falsification principle

Syllogism

consist of two broad statements (premises) and a conclusion

Categorical syllogism

statements being with"all", "no", or "some"

Ex: All teachers are inspiring.

Prf. DZ is a teacher

Prf. DZ is inspiring

Conditional syllogism

the first premise has "if... then" format

Ex: If I study, then I will get a good grade.

I studied .

I will get a good grade

Valid syllogism

the conclusion follows logically from the premises. Not all valid syllogisms are true.

Ex: All dogs are animals

All animals eat food

All dogs eat food

Valid syllogism but not true

Ex: all dogs are animals

All animals have wings

All dogs have wings

Invalid syllogism

the conclusion does not follow logically from the premises

Invalid syllogism though possibly true:

All dogs are animals

Some animals are small

Some of the dogs are small

Invalid syllogism and not true:

All dogs are animals

Some animals are in space

Some of the dogs are in space

Belief bias

the tendency to think a syllogism is valid if its conclusions are believable

- It is easier to see that the logic is invalid when using statements that also make it inaccurate

Falsification principle

to test a rule, it is necessary to look for a situation that would falsify it

-Cards corresponding to invalid syllogisms will not help you to test the rule

-Real life problems are easier to solve than abstract problems