11. Judgment, Decision Making, & Reasoning Flashcards
What is the difference between judgment and decision making?
Judgment involves deciding on the likelihood of various events using whatever information is available.
Decision making involves selecting from among several possibilities. Assess quality of our decisions in terms of their consequences (satisfaction).
Judgment often forms part of the decision-making process
What is reasoning?
Involves drawing inferences from the knowledge we possess.
What is support theory?
An event seems more likely when the various reasons why it might occur are stated explicitly.
(Eg. “What is the probability that you will die on your next summer holiday?” Vs “What is the probability that you will die on your next summer holiday from a disease, a car accident, a plane crash, or any other cause?”)
Why do we see an event as more likely when the possible causes are listed? (support theory)
Explicit descriptions draw attention to aspects of an event that are less obvious in non-explicit descriptions
Memory limitations mean people don’t remember all the relevant information if it isn’t supplied.
Even experts showed the above effect despite being able to fill in the details from their own knowledge
What is Base-Rate information?
The relative frequency with which an event occurs in the population. It is often ignored or deemphasized when individuals make a judgment.
On Krynski & Tenebaum’s False Positive Scenario (mammograms and breast cancer), why are base rates often neglected?
People assume that having breast cancer is the only cause of positive mammograms explicitly mentioned. base rates are more likely to be taken into account if we rephrased the problem to indicate that there is an alternative cause of positive mammograms. Neglect of base-rate information happens when the relevance of base-rate information to a judgment task is unclear.
Fred travels every day to work on a bus that departs every hour (6am, 7am, 8am) from the station.
After a long time, Fred notices that on average, 1/10 cases the bus departs before schedule, 8/10 cases it departs 0-10 min late, 1/10 cases it departs more than 10 min late.
Suppose that Fred arrives at the bus stop exactly on time and waits for 10 min without the bus coming, what is the probability that the bus will still arrive?
50% (not 10%)
The bus either already departed or it will depart more than 10min late. so its 10/20 chance which is 50%.
Base rates are over emphasized in this case because it is easy to calculate.
How do we induce people to pay more attention to base rate information?
Give them motivation to do so.
Eg. Put saliva on the paper. If it turns blue, means you have a health problem. But this test may be misleading 1/10 of the time. If the paper turns blue, people are more likely to pay attention to base-rate information to argue that they don’t have a health problem.
What is an advantage and disadvantage of using heuristics?
Advantage – require little cognitive effort
Disadvantage – often produce only approximately correct answers
What is the representative heuristic?
Involves deciding an object belongs to a given category because it appears typical or representative of that category. (Eg. Linda as feminist bank teller vs bank teller)
What fallacy are we making when we say that Linda is more likely to be a feminist bank teller than a bank teller? Describe the fallacy.
Conjunction fallacy – the mistaken belief that the conjunction or combination of two events (A and B) is more likely than one of the events on its own.
The description sounds more like that of a feminist bank teller than a bank teller. But this is wrong because p(feminist & bank teller) < p(bank teller) !
What is the availability heuristic?
Involves estimating the frequencies of events on the basis of how easy or hard it is to retrieve relevant information from LTM.
Eg. causes of death that attract more publicity (eg. murder, airplane crash) were judged as more likely to cause death than those that don’t (eg. suicide, car crash).
What are 2 mechanisms associated with the availability heuristic?
1) Availability-by-recall mechanism (based on the number of people that can be recalled having died from a given risk)
2) Fluency mechanism (based on how easy to recall without retrieving)
When do we NOT use the availability heuristic?
When we know the ones we retrieve easily fulfill a different criteria. (eg. we recall famous surnames more easily, but we know they are less common. “Bush” vs “Stevenson”)
Why do we still use heuristics in spite of their apparent problems?
Most of the time, being approximately correct is enough!
can be used almost regardless of the amount of information we have available.
What are fast and frugal heuristics?
Fast and frugal heuristics involve rapid processing of relatively little information
What does the “Take-the-best” heuristic propose?
Assumes you start with the most valid cue to drive your decision, in this case, how recognizable the city name is. The city whose name is more recognizable is assumed to have the larger population
What are the 3 components of “take-the-best” heuristic?
1) search rule - Search cues (eg. name recognition; cathedral) in order of validity
2) stopping rule - Stop after finding a discriminatory cue (ie. cue applies to only one of the possible answers)
3) decision rule - Choose outcome
What is the recognition heuristic?
When a judgment is made between two objects, it involves selecting the object that is recognized. It persists even in the face of conflicting information. (mainly when less valid cues are used as conflicting information. We rely more on valid cues.)
When will people NOT use fast-and-frugal heuristics?
When the decision is important (eg. choosing who to marry)
What does the natural frequency hypothesis propose?
We find it easy to work out the frequencies of different kinds of events we encounter in everyday life. Difficult to deal with fractions and percentages because they are more abstract. Performance would improve greatly if problems were framed in natural frequencies
When problem is phrased in terms of natural frequency as opposed to probabilities, what happens?
Judgment performance is better.
1) Conjunction fallacy dropped
2) Experts are more likely to use base-rate information
Provided participants with index card files organised into 2 categories:
With breast cancer vs No breast cancer
They had to select cards indicating whether the woman in question had a positive mammogram
What did the results show about people’s natural sampling behavior?
Participants’ sampling was heavily biased towards with breast cancer. They produced an average estimation of 63% that a woman had breast cancer given a positive mammogram. (correct answer 7.8%)
They believed mistakenly that it was more informative to select women with breast cancer than those without.
What does the dual-process model propose about probability judgments?
Probability judgments depend on processing within two systems - system 1 (automatic) & 2 (controlled)