PSYC 2421 Chapter 12 Judgement and Reasoning

Judgement

the process through which people draw conclusions from the evidence they encounter.

Why do people sometimes draw accurate conclusions from their life experience, and sometimes not?

Experience is the foundation for judgment.

Does the info we use when making judgements differ?

Yes. ex: should i go route a or b otw home?

Many judgements begin with a _______

frequency estimate

Assessment of how often various events have occurred in the past:

Ex: how many times have i got stuck in traffic otw home going this way

Often do not have ______ to frequency information

direct access

E.g., the job is new and you haven’t driven the route many times, or you typically take one route and have limited information about the other.

You’re relying on availability as a substitute for frequency.

Attribution substitution

relying on easily assessed information as a proxy for information needed

E.g., relying on availability instead of frequency

Heuristics- rules-of-thumb (strategies) for decision making that usually lead to the correct answer (4)

• Availability

• Representativeness

• Affect

• Effort

Affect heuristic

how does the outcome make you feel?

• ex: substantial dangers are often deeply frightening

How can affect lead to error?

Feelings are likely linked with little connection to the likelihood of the outcome

Effort heuristic

how much effort did you have to spend to gain the outcome?

• takes more work to remember things of higher value (exam content)

How can an effect lead to error?

Value is often independent of effort (ex: $20 earned vs $20 found on the street. What one is more valuable? The one you worked for.)

Availability heuristic

the ease that examples come to mind is a proxy for frequency

Accurate, the more frequently you encounter something the more it is in your memory

Ex: colds are more common in the winter because i see more people sick in the winter

Are there errors in judgement in the availability heuristic?

Yes!

Ex: Coverage of plane crashes

tests:

Test: in english, are there more words that start with r or with r in the third position?

The availability heuristic says we would say words start with r, in reality more words have r in third position

Test #2: Who does the housework more, you or your roommate?

The availability heuristic is likely to tell you yourself, because you are not aware/present when your roommate is doing them

Is it easy or hard to overestimate the freq of rare events because they are distinctive?

easy

Availability heuristics can influence how we view ourselves:

• Group of students asked to recall past episodes in which they had been assertive

• One group gave 6 examples, another gave 12 examples

• Those that gave 6 examples judged themselves as more assertive

• Easier to come up with 6 examples

Representative heuristic

the assumption that resemblance to the prototype reflects probability

Assumption of homogeneity

- an expectation that each individual is rep of the category overall

Likelihood of category mem is judged by resemblance

Ex: is this person an accountant or a poet? ( they are reading a book with a top hat)

• Representative heuristic will tell you a poet

• In reality, not everyone looks like the mental category we put them in

• There are more accountants, so this is more probable

What is the rep heuristic affected by? (2)

1. Stereotypes

2. Gamblers fallacy- Believe the seventh coin toss is more likely to be tails but the odds are still 50-50

The “prototype” of multiple coin tosses is an equal balance of heads and tails

When one outcome occurs many times in a row, you believe the opposite outcome is more likely to “correct” the sequence

Covariation

Making judgments about cause and effect

X and y covary, if the presence of x can be predicted by the presence of y

For example:

• Exercise and stamina

• Exercise and risk of heart attack

• Years of education and annual salary

Can be negative or positive, can vary in magnitude (strength), and you must check your belief about cause and effect.

T/F: Assumptions about covariation can lead to errors in judgment.

true

Illusions of covariation

- can falsely believe there is covariation when there is none

Ex: superstitions, blaire and the cemetary

Can illusions of covariations lead to selective attention towards data that seems to support covariation?

Yes! You see what you want to see ( peoples signs)

Confirmation bias

Confirmation bias

more responsive to evidence that confirms your beliefs (essentially ignoring information that doesn’t align with your

belief)

Ex: big dogs are vicious

Base rate information

info about how freq something occurs

Neglecting base rate info can lead to inaccurate estimates of covariation

Diagnostic info

descriptive info about a case

Ex: out of 100, how likely tom is an engineer?

2 groups: base rate info and diagnostic info

Base-rate information: 70 lawyers and 30 engineers

Diagnostic information: “Tom likes carpentry, sailing, math puzzles; dislikes politics”

One group given the base-rate with no diagnostic information, one given both the base-rate and diagnostic information.

Those given just the base rate information estimated the likelihood correctly, those given the diagnostic information ignored the base rate information and overestimated the likelihood that he is an Engineer.

Anchoring

when we don't know a value, we rely on heuristics to estimate the value

Ex: was MJ older than 2 when he died? Vs how old was MJ when he died?

Stages of anchoring:

Start with a ballpark, estimate, then adjust

The initial ballpark estimate “anchors” the judgment, and we usually adjust too little

Are judgments susceptible to anchoring effects by suggested values?

yes

note: If you first make a decision about an implausibly low anchor value, your later estimate will be too low

If you first make a decision about an implausibly high anchor value, your later estimate will be too high

What are some cases where humans reason well?

In some contexts, people seek out more accurate base rate info, are sensitive to sample size, seek potential sources of bias, etc.

Ex: your friend tells you how many times she won the lottery

Dual process models (2):

System 1 refers to thinking that is fast, automatic, and uses heuristics.

System 2 refers to thinking that is slower, effortful, and more likely to be correct.

When do you use system 1 or 2?

How much time you have

How much attention and WM is available

How the problem is presented ( what format the data is in -ex: 10% chance versus 1 in 10)

If there is less information available, what system are you using?

System 1

Emphasizing _______ will cue statistical thinking

Chance, highlighting the role of random chance

Descriptions of chance influence judgements: explicitly stating the role of random chance = system ___

2, how default is system 1

Can anything influence the likelihood of reasoning with system 2?

Yes, training.

Ex: taking a stats class improves reasoning

Statistical literacy=

Training can increase the likelihood you interact with S2

less base-rate neglect, less likely to need frequencies presented, etc.

T/F: thinking habits can predict deeper use of reasoning

true

induction vs deduction

Induction- make predictions about NEW cases based on past cases using probabilities

• Bottom up

Deduction- start with a general premises and use it to reason about individual cases

top down

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• Induction (bottom-up):

  • You meet 5 dogs, and all of them are friendly.

  • You conclude: “Dogs are usually friendly.”

  👉 You’re using specific cases → making a general prediction.
  👉 It could be wrong (you just haven’t met an unfriendly dog yet).

  Deduction (top-down):

  • Premise 1: All dogs are mammals.

  • Premise 2: A golden retriever is a dog.

  • Conclusion: A golden retriever is a mammal.

  👉 You’re using a general rule → applying it to a specific case.
  👉 If the premises are true, the conclusion has to be true.

Confirmation bias study: Wason (1966)

• Presented sequences like “2-4-6”

• Give participants time to figure out the rule by generating other sequences

Findings: They only sought confirming evidence

• “8-10-12”? Or “14-16-18”?

• Did not seek disconfirming evidence

• “10-8-6”? Or “1-3-5”?

researchers tend to do this

Confirmation bias

more responsive to evidence that confirms one's beliefs and less responsive to evidence that challenges one's beliefs

T/F: people show better mem for confirming evidence and distorted mem for disconfirming evidence.

true

Selective mem

reinterpreting disconfirming evidence

Ex: E.g., gamblers betting on a football game

• Wins are confirming evidence

• Losses are remembered as near-wins “I would have won if it weren’t for x...”

Belief perseverance

tendency to continue endorsing a belief even when evidence has completely undermined it

Example: Social sensitivity study (Ross et al., 1975)- Participants asked to determine whether a note was authentic or fabricated

• Given false feedback on their performance

• Even when told about random assignment to groups, rated themselves as having lower sensitivity

findings

Confirmation bias: selectively sought episodes in memory in which social sensitivity was lacking

People who got rated as low socially sensitive, they rated themselves lower later, even knowing the experiment was fake.

Utility theory

Utility theory is the idea that people make decisions by choosing the option that gives them the highest “utility”, meaning the most satisfaction, value, or benefit to them.

Do our decisions follow the principle of utility maximization, or choosing the option with the greatest expected value?

yes

framing

can impact how we interact with utility maximization

T/F: when loss is emphasized, we are more likely to seek risk than when gain is emphasized?

true

When people think in terms of gains, they tend to play it safe to protect what they already have.

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Gain frame:

Option A: Get $500 for sure

Option B: 50% chance to get $1000, 50% chance to get $0

👉 Most people choose Option A (safe choice)

Loss frame:

Option A: Lose $500 for sure

Option B: 50% chance to lose $1000, 50% chance to lose $0

👉 Most people choose Option B (riskier choice)

do we always rely on utility assessments

no

Reason based choice

the idea that people make a decision only when they detect what they believe to be a persuasive reason for making that choice.

?

Giving more choices decreases the justification to choose a specific one ( when you get more choices you are less likely to make a decision all together)

Paradox of choice

if an argument cant be justified/not persuasive enough we wont accept it

T/F: Anticipated events can produce physio arousal

True

Ex: having increased HR, butterflies, sweating

What part of the brain is essential for evaluation of somatic markers (bodily-based emotional signals that guide decision-making)

The orbitofrontal cortex (what???)

T/F: Patients with orbitofrontal damage will make risky decisions

They have a failure to recognize “gut feelings”

continue to draw from the high risk stack

Affective forecasting

how well can we predict our own emotions

Are we bad at predicting future feelings?

Yes. we can predict the emotion but not the magnitude