CHAPTER FOUR Bayes in the World Flashcards
What is Bayes’ theorem ideal for?
Decision-making
Who are the psychologists known for their research on human irrationality?
Daniel Kahneman and Amos Tversky
What heuristic leads people to judge risks based on how easily they can think of examples?
Availability heuristic
What fallacy occurs when people mistakenly think that the probability of both A and B occurring is greater than either A or B occurring alone?
Conjunction fallacy
What effect shows that people’s decisions can change based on how information is presented?
Framing effects
True or False: Framing a problem can influence people’s decisions even if the logical content remains unchanged.
True
What was the percentage of medics who answered a question about disease prevalence correctly in a 1978 study?
18.33% (11 out of 60)
Fill in the blank: Humans tend to make basic logical mistakes due to _______.
Cognitive biases
What is the result of a 2011 study regarding junior obstetrics and gynecology doctors answering a question about breast cancer?
Only 26% got it right
What does Jens Koed Madsen suggest about human decision-making in everyday life?
Humans are rational in 90% of their decisions
What is Wason’s selection task designed to illustrate?
Confirmation bias
In Wason’s selection task, what are the correct cards to turn over?
The 8 and the young woman
What do people often fail to do in logical reasoning tasks, according to Madsen?
Look for ways to falsify a hypothesis
Fill in the blank: The selection task shows that humans are highly prone to _______.
Confirmation bias
What did a 1992 study find regarding participants’ performance in a natural versus abstract reasoning task?
75% got it right in a natural context
What is the significance of the replication crisis in psychology mentioned in the text?
It challenges the reliability of previous findings
True or False: The framing of a question can lead to different decision outcomes even when the logical content is equivalent.
True
What do the studies mentioned suggest about the rationality of humans?
Humans are rational when information is presented in familiar ways
According to the text, what is a common misconception about human decision-making?
That humans are deeply irrational
What is the main argument about human reasoning in familiar formats?
Humans are good at reasoning when it takes place in a familiar format.
Who conducted research on the San tribe’s reasoning abilities?
Louis Liebenberg
What does the heel of a porcupine’s paw have that distinguishes it from a honey badger’s paw?
Two proximal pads
In Bayesian reasoning, what is the difference between sampling probability and inverse probability?
Sampling probability is the chance that a one-pad print is left by a honey badger; inverse probability is the chance that a one-pad print has been left by a honey badger.
What is the prior probability in the context of the San’s reasoning about paw prints?
The likelihood of finding an ambiguous print from a common animal rather than a rare one.
What common phenomenon demonstrates people’s differing reactions based on their beliefs about politicians?
People react differently to the same speech based on whether they like or dislike the politician delivering it.
What did Madsen and colleagues find about voters’ opinions on policies based on politicians’ trustworthiness?
Voters’ prior beliefs influenced their opinions on policies supported or attacked by those politicians.
What heuristic allows humans to make quick decisions under uncertainty?
Mental heuristics
What is the availability heuristic?
A mental shortcut that relies on immediate examples that come to mind.
What is the gaze heuristic as described by Gerd Gigerenzer?
Fix your gaze on the ball, start running, and adjust your running speed so that the angle of gaze remains constant.
What did the Royal Air Force discover about the gaze heuristic in WWII?
They could use it to guide fighters to intercept bombers more quickly than calculating trajectories.
What do biases in human decision-making often result from?
Shortcuts and heuristics that misfire under certain conditions.
What is recency bias?
The tendency to overweight more recent evidence.
What is anchoring bias?
The tendency for the first piece of information encountered to set expectations.
What is frequency bias?
The tendency to rely more heavily on information that has been encountered most often.
What was a significant irrational choice made by Americans after September 11, 2001?
Choosing to drive long distances more, leading to increased driving deaths.
What is the mistake in the reasoning behind vaccine hesitancy?
Low trust in public health systems leads to distrust in vaccines.
What is the Monty Hall problem?
A probability puzzle involving choosing between three doors, one of which hides a prize.
What happens after a contestant chooses a box in the Monty Hall problem?
The host opens another box that is empty and offers the contestant a chance to switch.
What does switching boxes in the Monty Hall problem increase the probability of winning?
It increases the probability to 2/3.
What was the reaction of some mathematicians to Marilyn vos Savant’s solution to the Monty Hall problem?
Many were angry and insisted she was wrong.
What does the Monty Hall problem illustrate about human understanding of probability?
Many people struggle with formal probabilistic thinking.
What is a common misconception about the probability of winning in the Monty Hall problem?
That switching boxes does not change the probability.
What is the general public’s common misconception about the Monty Hall problem?
Most people think the true probability is 50 percent and that it makes no difference if you switch.
What should you do when presented with the Monty Hall problem, assuming Monty knows where the car is?
You should switch doors.
In the Monty Hall problem, what is the probability that you initially picked the correct door?
One-in-three, or approximately 0.33.
What happens to the probabilities after Monty opens a door to reveal a goat?
The odds change, making it more likely that the car is behind the other unopened door.
What happens to the prior odds if Monty doesn’t open a door with a goat?
The prior odds remain 1:1:1, and switching becomes irrelevant.
What does Bayesian reasoning require in the context of the Monty Hall problem?
It requires using all available information about Monty’s behavior.
What is the ‘Boy-Girl paradox’?
It refers to the probability of having two boys when at least one child is known to be a boy.
What is the probability of a parent having two boys if one is known to be a boy?
One-third.
How does the knowledge of the elder child being a boy affect the probability of the other child being a boy?
It changes the probability to 50 percent.
What significant event occurred in 1983 that nearly led to nuclear war?
The Soviet Union mistook NATO’s Able Archer war game for a real attack.
Who was the ‘well-placed spy’ that helped prevent a nuclear conflict during the Cold War?
A spy in the KGB’s London headquarters.
What was Philip Tetlock’s role in the National Research Council’s panel?
He was the least impressive member but observed differing opinions on Soviet leadership.
What unexpected event occurred after Chernenko’s death that neither liberals nor conservatives predicted?
The appointment of Mikhail Gorbachev as a reformer.
What policies did Mikhail Gorbachev implement?
Glasnost (openness) and perestroika (restructuring).
What did Tetlock conclude about the experts’ predictions following unexpected events?
Experts tended to reinterpret events to fit their existing beliefs.
How many predictions did Tetlock’s study involve?
More than thirty thousand predictions.
What was a key feature of the predictions made in Tetlock’s study?
They were falsifiable and time-limited.
What was the main purpose of Tetlock’s study involving 284 experts?
To gather predictions from experts on various events that were falsifiable and time-limited.
Why did Tetlock emphasize the need for precise numbers in predictions?
To avoid vague verbiage and ensure clarity in what experts mean by likelihood.
What is the Brier score used for?
To assess the accuracy of forecasts by calculating the squared error of predictions.
How is the Brier score calculated after a forecast is made?
By squaring the error between the forecast probability and the actual outcome.
What distinction did Tetlock make between ‘hedgehogs’ and ‘foxes’?
Hedgehogs have one big idea for predictions, while foxes consider multiple factors and complexities.
Who did Tetlock consider to be a ‘superforecaster’?
Individuals who excel at forecasting by thinking in Bayesian terms and incorporating prior probabilities.
What is the ‘inside view’ in forecasting?
Judging probability based on the specifics of the current situation.
What is the ‘outside view’ in forecasting?
Judging probability based on historical data and similar past events.
What is the significance of using base rates in forecasting?
Base rates serve as a starting point for making probability judgments.
Fill in the blank: The classic example of a Fermi estimate is estimating the number of _______ in Chicago.
piano tuners
What was Larry Kudlow’s big idea according to Tetlock?
Supply-side economics, specifically that tax cuts stimulate the economy.
True or False: The average forecaster in Tetlock’s study performed significantly better than random guessing.
False
What was a notable regret of Tetlock regarding his comparison of forecasters to a ‘dart-throwing chimpanzee’?
That people misunderstood it to mean all experts were guessing randomly.
What did Tetlock find about the predictions made by the top 2% of forecasters?
They were significantly better than random guessing and excelled at forecasting.
What is a key characteristic of superforecasters according to Tetlock?
They update their predictions based on new information while considering prior probabilities.
What is an example of a situation where a superforecaster might use the outside view?
Assessing the likelihood of a marriage succeeding based on divorce rates.
Fill in the blank: The error in Brier score calculation is squared to ensure that _______ errors are treated positively.
negative
What can affect how much a forecaster updates their predictions away from the base rate?
Judgment on the relevance of new information.
What does Tetlock’s example of estimating piano tuners illustrate?
The effectiveness of breaking down complex problems into manageable parts.
What was the probability question posed about Yasser Arafat’s death?
Will inquiries find elevated levels of polonium in Arafat’s remains?
What approach do superforecasters take when faced with new data?
They assess how much to adjust their beliefs based on the new information.
What was the inquiry regarding Yasser Arafat’s body?
Whether elevated levels of polonium would be found in his remains
This inquiry led to a probability assessment by forecasters.
What is a common pitfall in making probability assessments according to Tetlock?
Leaping to conclusions without reflection
This often results in assigning extreme probabilities.
What method did a superforecaster use to assess the probability of finding polonium?
Breaking down the question into parts
This includes estimating how polonium could enter Arafat’s body and its decay time.
What is a Fermi estimate?
A method of making several small estimates instead of one big estimate
This utilizes the law of large numbers.
How do good forecasters utilize the wisdom of the crowds?
They update their forecasts based on others’ predictions
The average of several forecasters’ predictions tends to be more accurate.
What should you consider when evaluating forecasters’ predictions?
Their track record and calibration
Some forecasters may have a history of inaccurate predictions.
What is the significance of keeping score in forecasting?
It allows forecasters to track the accuracy of their predictions
This helps prevent forgetting bad predictions.
True or False: People tend to be underconfident in their probability assessments.
False
People are typically overconfident in their assessments.
What is the typical result when people are asked to give a 90 percent confidence interval?
Their intervals often reflect a 50 or 60 percent confidence level
This indicates a high rate of incorrect confidence assessments.
What is required to make Bayesian claims about probabilities?
Some sense of prior probabilities
Without prior knowledge, claims about likelihood after evidence cannot be made.
What is the challenge in predicting events like the Russian invasion of Ukraine?
Finding suitable base rates for comparison
This involves determining the average occurrences of similar conflicts.
What does Jonny Kitson say is crucial for superforecasting?
Choosing the right base rate
Recognizing when the base rate is off is also vital.
How does Bayesian reasoning help with definitions and categories?
It accommodates fuzzy definitions and recognizes family resemblances
This approach contrasts with strict Aristotelian definitions.
What is a philosophical issue related to the concept of ‘heap’?
Determining when a collection of sand ceases to be a heap
This paradox challenges clear boundaries in definitions.
What is the Bayesian perspective on subjective probability assessments?
It allows for confidence levels to shift gradually
As evidence changes, so does the confidence in categories.
What is one major benefit of a Bayesian view on the world?
It resolves many philosophical conundrums
This includes issues related to definitions and identities.
Fill in the blank: The average number of land wars in Europe per year is a _______.
base rate
Base rates are critical for making informed predictions.
What does sand constitute?
a heap
What Aristotelian problem does the text mention?
hard definitions and clear boundaries between categories
What is the nature of the world according to the text?
not black and white; it is shades of gray
What does the author acknowledge about beliefs and definitions?
they are probabilistic
According to the text, what can help us predict the world?
beliefs that best meet incoming information and avoid prediction error
What does rational behavior mean in decision theory?
the most likely way to achieve some goal
What percentage of couples got divorced in England and Wales in 2021?
0.9 percent
What is the probability of a marriage surviving a given year based on the 2021 statistics?
0.991
What is the estimated percentage of marriages that end in divorce after fifty years?
about 37 percent
What was the author’s accuracy rate for 80 percent guesses?
85 percent of the time
Fill in the blank: The belief that nothing is knowable at all is attributed to _______.
Paul Feyerabend or Robert Anton-Wilson
True or False: The text suggests that all beliefs are equally valid.
False
What does the author mean by ‘shades of gray’?
different shades of certainty regarding beliefs
