thinking: judgement

reasoning

solving problems that involve the rules of logic

logic

a formal “algorithm”

who is the syllogism after?

aristotle

syllogism particularly focuses in on what terms

ALL or SOME terms

structure of the syllogism

• two statements that kick the problem off; premises

• a conclusion statement, that may or may not follow from the premises

“Statement 1: All Kpelle men are rice farmers
Statement 2: Mr Smith is not a rice farmer
Conclusion: Mr Smith is not a Kpelle man”

• some studies would ask if the conclusion follows the premises (yes/no)?

  • can analyse these types of data with signal detection theory (SDT); where both the intensity of the stimulus AND the psychological state of the person contribute to whether or not the person is able to detect the stimuli

• involve mainly these three operators (all, some, no)

what is a formal set of rules

the ALGORITHM; follow the set of rules to solve these problems exactly/perfectly

judgement as the area of thinking is concerned with our ability to estimate ______ of events?

likelihoods

what is a heuristic

bit like a cheat; a shortcut; or rule of thumb, to avoid the algorithm (cuz that effortful and takes a long time)

the key aspect when you think about these reasoning problems, the ______ of the problem is determined entirely by its ___________.

the key aspect when you think about these reasoning problems, the VALIDITY of the problem is determined entirely by its LOGICAL STRUCTURE. the actual content of these syllogisms, is completely irrelevant.

• can be set up with any scenario you want and it doesn’t change its logical structure

• means they can be set up with content that makes no sense or is completely ridiculous

belief bias

in the syllogism, even tho both of the problems’s logical structure is equivalent and valid, people do not accept problem 2 because the statement conflicts with their beliefs about the world

• even though there is an algorithm people dont seem to follow the algorithm and tend to evaluate the scenarios at a more surface level.

how do people handle probabilities?

likelihood of dying by various causes (Lichtenstein et al (1978)

• we over-estimate rare causes of death and under estimate common causes

the availability heuristic

an estimate based on the EASE of which we can bring specific examples to mind.

heuristic = shortcut

• can lead to bad assessments as we tend to remember somethings more easily than others

• cant trust intuition to realistically calculate risk

“A person is said to employ the _____ whenever he estimates frequency or probability by the ease with which instances or associations could be brought to mind” (Tversky & Kahneman 1973)

the availability heuristic

what is our mental lexicon in relation to “Which is more likely, that a word in English begins with the letter K or has K as its third letter?”

mental vocab

• the only way we can search our mental lexicon is by the first letter of words

• its much easier to bring examples to mind that begin with k

heuristics

shortcut/rule of thumb/cheat/tricks that do not always work, but work pretty well.

• avoids you having to work through the actual probability theory, in the case of these judgement problems

many heuristics can be expressed as if, then statements: “if i can think of more examples of something, then it is more likely to happen”

• can give rise to ridiculous responses

Which of these statements is NOT true of heuristics?

A. They allow judgments to be made quickly
B. Using heuristics is an indication of low intelligence
C. They are well suited to everyday situations
D. They generate an answer that might not be the best
answer, but it is often good enough for your current needs
(this is called ‘satisficing’ – a useful concept for
undergraduates in the last few weeks of term!)

B

base rate neglect

people forget about the initiale situation (base rate) after being given new info

the representativeness heuristic

a likelihood estimate of an event based on how similar it is to a known situation (the new evidence)

the engineers and lawyers problem

Two groups of subjects:
- Group A told sample of 100 contains 30 engineers and 70 lawyers
- Group B told same sample contains 30 lawyers and 70 engineers

(this is the base rate that they are about to neglect)

“Dick is a 30 year old man. He is married with no children. A man of high ability and motivation, he promises to be quite successful in his field. He is well liked by his colleagues. What is the probability that Dick is an engineer?”

» Group A: 50%
» Group B: 50%

participants in both groups just focus on the description, even though they can recall the info but consider it irrelevent

the linda problem

most famous Tversky & Kahneman portfolio

starts of with a vingette (base rate):

“Linda is 31 years old, single, outspoken and very bright. She majored in Philosophy. As a student, she was very concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations. Which descriptions are most likely to be true of Linda?

Rank in order of how likely they are to apply to linda:
1. Linda is a bank clerk
2. Linda is active in the feminist movement
3. Linda is a bank clerk and active feminist
...

Tversky & Kahneman (1983)

not rlly interested in two but the relative position of 1 and 3

• people make the mistake of putting 3 higher up than 1, but the number of feminist bank clerks in the world has to be a subset of the number of bank clerks, because the chances of being two things is smaller than the chances of being one: the CONJUNCTION FALLACY

the conjunction fallacy

the linda problem

• a cognitive bias where where people mistakenly judge the probability of two events happening together to be higher than the probability of either event happening alone

  • violates the basic probability theory as the probability of a conjunction can never be greater than the probability of either of its parts

why does the conjunction fallacy happen

because people use the representativness heuristic

psychology research on reasoning often uses ______. people struggle to engage with deeper _____ _____ of these statements.

syllogisms, logical structure

in research on judgement people over-estimate _____ events, under-estimate _____ events, and look for mental _____ on more complex problems.

rare, common, shortcuts (heuristics)

two common heuristics are the ______ heuristic, and the ______ heuristic. heuristics rely on built in properties of our ______ ______.

availability, representativeness, cognitive systems