11. Decisions, Judgements + Reasoning

General themes

________________ -  From the standpoint of formal logic and probability, humans do not always reason well

 General world knowledge and pre-existing knowledge often has too much influence on human reasoning

• Prior knowledge and beliefs influence our reasoning abilities

• Confirmation Bias

People usually (but not always) reason better with concrete vs. abstract material

• Ex: Echo chambers in manosphere politics

Confirmation bias

General themes

______________ - we tend to seek out confirmatory evidence to support our beliefs, and we do not seek out or ignore evidence that contradicts our beliefs

A focus on errors

___________ -  In this topic we focus on errors = not that we cannot process info or are “dumb”

Errors are the cost of quick, efficient mental processing

•  Dual Process View

When have you seriously gone and wondered if you were wrong about something?

Dual process model of thinking

A focus on errors

_____________ -  System 1 uses intuitive thinking (Fast; heuristics) & System 2 usees analytical thinking (Slow; Analytic)

• ­Tversky & Kahneman

People with lower domains of knowledge have a tendency to find themselves MORE correct than those with actually higher domains of knowledge

System 1 thinking → intuitive

Dual process model of thinking

______________ - ­Quick and reflexive

• ­Little mental effort required

• Relies on heuristics, → don’t have to even think about it

  • Stereotypes on race, saying “bread”– then “butter”

System 2 thinking → analytical

Dual process model of thinking

_______________ - ­Slow and reflective; deliberate

• ­Requires mental effort

• Effortful- uses conscious resources

  • Ex: Figuring out what uni major you’re doing

Cognitive misers

Dual process models of thinking

_______________ -  allows us to simplify our world and attend primarily to what is meaningful and manageable.

• ­Heuristics often work very well, or good enough

• ­There can also be problems with heuristic thinking

  • ­Stereotypes based on superficial differences like race can be problematic

Humans are….. ____________

• ­We are frugal + stingy with our limited mental energy

• ­System 2 uses mental energy

“Fast and frugal”

________________ - System 1 is..

• ­We need to process huge amounts of information all of the time

Arguments

Reasoning

_______________ -  split into two parts:

1. ­Premises: Basic principles or assertions

2. Conclusion: A statement that is established or supported by the premises.

Example:

1. ­All Dogs are Mammals    (Premise)

2. ­Teddy is a Dog  (Premise)

3. ­Therefore, Teddy is a mammal   (Conclusion)

Premises

Reasoning → parts of arguments

____________ - ­Basic principles or assertions

Example:

• ­All Dogs are Mammals

• Teddy is a Dog 

Conclusion

Reasoning → parts of arguments

____________ - ­A statement that is established or supported by the premises

Example:

• ­Therefore, Teddy is a mammal

Deductive reasoning

________________ -  An argument that, if valid (proper logical form) must be true if the premises are true

• ­If the premises are true, the conclusion must be true if the argument uses a valid logical form

• Logically valid arguments do not have to have true premises

• Meaning of valid

Deduction example

Deductive and inductive reasoning

_____________ - ­60% of the people called said they are Democrats

­Therefore, 60% of the people called are Democrats

Induction example

Deductive and inductive reasoning

_____________ - ­60% of the people called said they are Democrats

­Therefore, approximately 60% of voters in the country are Democrats

Inductive reasoning

______________ -  An argument that, if strong, provides good evidence to support the truth of a conclusion

• ­If the premises are true, the conclusion is likely to be true

Valid

Deductive and inductive reasoning → deductive reasoning

____________ - Must guarantee the truth of the conclusion

Syllogisms

_______________ - A three-statement logical form, with the first two parts stating the premises and the third part stating a conclusion based on those premises

Deductive reasoning using categories— drawing conclusions based on group membership

• Based on statements about categories or groups (like "all," "some," "none").

• Syllogistic reasoning vs. conditional reasoning

Conditional reasoning

_____________ - (aka “if-then” reasoning). Drawing conclusions based on if conditions were met or not.

Based on cause-effect or if-then logic.

• Classic format:

  • If A happens, then B will happen.

  • A happened.

  • Therefore, B will happen.

Syllogistic reasoning example

Syllogisms and conditionals

______________ - Are conditions being met, or are conclusions drawn based on group membership?

• All A are B

• All B are C

• Therefore, all A are C

Example:

• All humans are mortal.

• Socrates is a human.

• Therefore, Socrates is mortal.

Conditional reasoning example

Syllogisms and conditionals

______________ - Are conditions being met, or are conclusions drawn based on group membership?

• If P, then Q   (______ Statement)

• P   (Evidence)

• Therefore, Q   (Conclusion)

Example:

• If it rains, the ground gets wet.

• It rained.

• So, the ground is wet.

Affirm consequence → valid/logical

Conditional reasoning — valid or not?

• If I am a freshman, I have to register today

• I am a freshman

• Therefore, I have to register today

Deny consequence → not valid/illogical

Conditional reasoning — valid or not?

• If I am a freshman, I have to register today

• I am not a freshman

• Therefore, I do not have to register today

Affirm consequence → not valid/illogical

Conditional reasoning — valid or not?

• If I am a freshman, I have to register today

• I have to register today

• Therefore, I am a freshman

Deny consequence → valid/logical

Conditional reasoning — valid or not?

• If I am a freshman, I have to register today

• I do not have to register today

• Therefore, I am not a freshman

Errors in conditional reasoning

Conditional reasoning

______________ -  People are good at affirming the antecedent

People often make errors with these types of conditional reasoning

• ­Mistake conditional statement “IF P, THEN Q” for biconditional statement (I.e., “IF P, THEN Q” = “IF Q, THEN P”)

• Research indicates people make these errors even when comprehending discourse (e.g., Sloutsky, 2002)

Wason Selection Task

_____________ -  If a card has a vowel on one side, then it must have an even number on the other side

Human reasoning task – participant job is needed to verify OR disconfirm this rule

• Most people turn around E and 4 but they are both incorrect, and instead signs of confirmation bias. The correct combo was 7 (odd no.) and E (vowel) to see the disconfirming evidence

Confirmation bias in the Wason Selection Task

Wason Selection Task

______________ - Choosing E and 4 is an example of the confirmation bias:

­We seek out confirming evidence, or information that is consistent with a hypothesis, rather than inconsistent information

 ____________ is pervasive in human reasoning

•  Myside Bias

Myside bias

Wason Selection Task → Confirmation bias

______________ - the tendency to be over-swayed by a prior opinion on a topic, failing to give enough weight to evidence or arguments to the contrary

Availability heuristic

Heuristics

_________________ -  Estimates are influenced by the ease with which relevant examples can be remembered

• ­A simple shortcut where we make estimates based on what we can think of

 Biases within the availability heuristic

• ­General World Knowledge

• ­Familiarity Bias

• ­Salience and Vividness Biases

Examples of availability heuristic

Availability heuristic

____________- ­What proportion of households in Canada have an iPad?

­How likely are you to be harmed by a terrorist attack?

General world knowledge

Availability heuristic

_______________ - Our existing knowledge factors into our estimates

• Example: Estimate the ratio of the number of Chevrolets sold to the number of Cadillacs sold

­People may incorporate what they know about these vehicles into their estimate: the cost and how many people are likely to be able to afford a Cadillac

Familiarity bias

Availability heuristic

_______________ -  Judging events as more frequent or important because they are more familiar

• Example: Tversky & Kahneman

  1. ­Food additives

  2. ­Political candidates

• People think famous/familiar names are more common even if that is not the case

People play on familiarity on ads to continue bringing it up, like how PP is bringing up identity politics to Canada when it has never been like that before

Salience + vividness biases

Availability heuristic

_______________ - A particularly notable or vivid memory influences judgments about the frequency or likelihood of such events

 Is it safer to travel by car or airplane?

• ­25 times safer to travel by airplane

Example of familiarity bias

Availability heuristic → familiarity bias

_____________ - ­ Tversky & Kahnema

Gave people lists with 39 names (19 women’s names and 20 men’s names per list)

­Some Ps had to recall names, some had to estimate if there were more men’s than women’s names

­In some lists the men’s names were famous (but not the women’s), in others the women’s names were famous (but not the men’s)

• ­Results: People could recall more famous names (12/19) than non-famous names (8/20)

• ­Results: People estimated that there were more names in the men’s or women’s list if the names were famous

Familiarity affects our judgment beyond estimates of frequency

Simulation heuristic

Heuristics

______________ -  A mental construction or imagining of outcomes; a forecasting of how some event will turn out or how it might have turned out under different circumstances

• ­Also includes possible events

• ­Guided by the ease with which the possible outcomes come to mind or can be imagined (heuristic)

Difficulties imagining

Simulation heuristic

____________ - When imagining a scenario, alternatives that are difficult to imagine or seem less plausible are judged as unlikely to occur

• ­If an alternative is difficult to imagine no mental scenario will be formed, therefore it will not be judged as likely or unlikely to occur at all

• ­If you cannot imagine possibility A, you cannot consider possibility A

If we can mentally construct a picture or imagine it– it can be thought to be more likely. If you cannot imagine a possibility, you cannot consider that possibility

Example of simulation heuristic

Simulation heuristic

_______________ - Kahneman & Tversky (1982)

• Mr. Crane and Mr. Tees were scheduled to leave the airport on different flights, at the same time.

• They traveled from town in the same limousine, were caught in a traffic jam, and arrived at the airport 30 minutes after the scheduled departure time of their flights.

•  Mr. Crane is told that his flight left on time. Mr. Tees is told that his flight was delayed, and just left five minutes ago.

 Who is more upset, Mr. Crane or Mr. Tees?

• Mr. Crane: Missed his flight by 30 minutes (it left on time).

• Mr. Tees: Missed his flight by just 5 minutes (it was delayed)

People assume Mr. Tees is more upset because they can imagine themselves in his shoes more easily

Representativeness heuristic

Heuristics

______________ -  An estimate of the probability of an event is determined by one of two features:

1. ­How similar the event is to the population of events it came from

2. ­And/or whether the event seems similar to the process that produced it

Random Processes

Random processes

Representativeness heuristic

____________ - ­If a coin is tossed 6 times, which is more likely to occur?:

H H H T T T    or    H H T H T T

Representativeness of the parent population

Representativeness heuristic

_______________ -  Kahneman & Tversky (1972)

• ­There are two hospitals in a town. In one, about 45 babies are born each day. In the other, only about 15.

• ­About 50% of all babies are boys, although on any day this percentage may be higher or lower

• ­Across one year, the hospitals recorded the number of days on which 60% or more of the babies were male.

­Which hospital do you think had more such days?

Results:

• ­28/50 Ps said the hospitals would be the same

• ­12/50 Ps said it was the larger hospital

• ­10/12 Ps said it was the smaller hospital

Correct Answer:

The smaller hospital.
Because smaller samples have more variability—so they’re more likely to swing to extremes like “60% boys.”

Ignoring base rates

_______________ - Kahneman & Tversky (1973)

Read various personality descriptions to people

• ­Ps were asked to estimate the probability that the described person was a member of one or another profession:

• ­Psychologists interviewed and tested the personalities of 30 engineers and 70 lawyers’

What is the probability that the person is an engineer?

• ­Jack is a 45-year-old man. He is married and has four children. He is generally conservative, careful, and ambitious. He shows no interest in political and social issues and spends most of his free time on his many hobbies, which include home carpentry, sailing, and mathematical puzzles

• ­A person named Bill was randomly selected from the roomful of 100 people.

Thinking of heuristics adaptively

_______________ -  Gigerenzer (1996) Heuristics are adaptive, used to save mental resources and they work!

They are fast and frugal:

• Satisficing

• Recognition heuristic

• “Take the best” heuristic

Other viewpoint on heuristics on how they aren’t always problematic, but can be adaptive. (two sides of the coin, sometimes they can be helpful as well)

Satisficing

Thinking of heuristics adaptively → fast and frugal heuristics

______________ - decide by taking the first solution that satisfies some criterion we may have

• ­the “good enough” heuristic

  • ­Ex: You’re really hungry, but have somewhere to be in an hour– are you going to risk weighing each restaurant to sate your hunger? No, you’ll get something quick to eat here

Recognition heuristic

Thinking of heuristics adaptively → fast and frugal heuristics

______________ -  base a decision on whether we recognize the thing to be judged

“Take the best” heuristic

Thinking of heuristics adaptively → fast and frugal heuristics

______________ -  decide between alternatives based on the first useful information we find