Module 4 - Manley Ch 5 - Evidence Flashcards
What is “evidence” in reasoning?
Evidence is any observation or fact that helps assess the likelihood of a hypothesis being true or false, guiding reasoning across disciplines.
What are the two key tests for assessing evidence?
The Evidence Test: Is the observation more likely if the hypothesis is true or false?
The Strength Test: How much more likely is the evidence if the hypothesis is true than if it is false?
What is the first rule of evidence?
Evidence should increase our confidence in a hypothesis, though the degree of increase depends on the evidence’s strength.
How do we measure the strength of evidence?
By comparing how likely the evidence is if the hypothesis is true versus if it is false, expressed as a “strength factor.”
What is a “strength factor”?
The number of times more likely the evidence is given that a hypothesis is true compared to when it is false (e.g., a strength factor of 10 means the evidence is 10 times more likely if the hypothesis is true).
What is the significance of a strength factor of less than 1?
It indicates that the evidence is less likely if the hypothesis is true, making it evidence against the hypothesis.
How confident should we be in a hypothesis when evidence has a strength factor of 10?
Confidence depends on both the strength of the evidence and prior confidence in the hypothesis; a strength factor of 10 strongly supports the hypothesis but doesn’t multiply confidence by 10.
When is evidence maximally strong for a hypothesis?
When the evidence could only occur if the hypothesis is true, making the probability of the evidence under the hypothesis being false equal to zero.
What is “independent evidence”?
Observations that are equally likely whether a hypothesis is true or false, providing no support for or against the hypothesis.
How does the strength of evidence relate to suppositional strength in arguments?
The stronger the evidence provided by premises, the greater the suppositional strength of the argument’s conclusion.
What happens if evidence supports both for and against a hypothesis?
The overall support depends on the relative strength of the evidence for each side.
What is the relationship between evidence and reasoning?
Responsiveness to evidence is central to reasoning, helping us update our beliefs and evaluate hypotheses effectively.
How does the strength test compare pieces of evidence?
By quantifying how much more likely each piece of evidence is under the hypothesis versus its negation, enabling precise evaluation.
How is “probability” defined in the context of this text?
Probability is our degree of confidence in a claim, represented as a value between 0 (certainly false) and 1 (certainly true).
What is the relationship between probability and confidence?
Probability expresses how confident we are that a claim is true, such as being 50% confident equating to a probability of 0.5.
What rule ensures probabilities are consistent?
The probabilities of a hypothesis (H) and its negation (not-H) must add up to 1 (e.g., if H is 0.8, not-H must be 0.2).
What is the Strength Test in evaluating evidence?
It compares how likely the evidence is if the hypothesis (H) is true versus if it is false, giving a strength factor.
What is the Opposite Evidence Rule?
If a piece of evidence (E) supports a hypothesis (H), then the absence of that evidence (not-E) supports not-H.
What is “Heads I win, Tails we’re even” bias?
A cognitive bias where evidence supporting a view is accepted, but evidence against it is dismissed or ignored.
Why is considering the opposite view important in evaluating evidence?
It helps avoid biased evaluation by forcing us to think about how likely evidence would be if the hypothesis were false.
What is Suppositional Strength?
The degree to which premises support a conclusion if the premises are true, evaluated as evidence for the conclusion.
Why must both sides of the Strength Test be evaluated?
Only considering how evidence fits with H (and not how it fits with not-H) can lead to overestimating its support for H.
Can evidence against a hypothesis be weaker than evidence for it?
Yes, evidence against H might be weaker than evidence for H, but it is still evidence that should adjust our confidence.
How does cognitive bias affect evidence evaluation?
Bias can cause us to dismiss evidence against our views or overvalue evidence that aligns with them.
What is the value of assigning probabilities to unique events?
It reflects our confidence in the event, even though the event is already determined (e.g., “It’s probably raining”).
Why should probabilities of a claim reflect relevant statistical facts?
Confidence in a claim (e.g., a coin toss being heads) should be informed by known probabilities (e.g., 50%).
What does failing to find supporting evidence imply?
A lack of supporting evidence provides some evidence against a claim, with strength depending on how much was searched.
How can we counter confirmation bias when faced with evidence?
By considering how we would react to the opposite evidence and adjusting our confidence accordingly.
What happens if evidence could only occur if the hypothesis is true?
The evidence is maximally strong for the hypothesis because it could not arise under not-H.
What is a selection effect?
A factor that filters which observations are available, potentially making evidence unreliable if the filtering isn’t recognized.
What is survivor bias?
A type of selection effect where only successful or surviving cases are observed, leading to misleading conclusions about success rates or outcomes.
How does attrition bias affect studies?
It occurs when participants drop out of a study in ways that bias the results, such as happier or unhappier individuals being more likely to leave.
What is selective noticing?
Paying more attention to evidence that supports a hypothesis while ignoring or failing to register disconfirming evidence.
What is the availability heuristic, and how does it relate to memory?
A cognitive shortcut where things that come to mind easily are assumed to be common or probable, influenced by emotional intensity, framing, or event order.
What is the serial position effect?
The tendency to remember the first and last items in a series or event better than the middle ones.
What is media bias in the context of selection effects?
Media outlets tend to prioritize content that engages viewers, often favoring stories that elicit fear or rage, regardless of their actual relevance or proportional impact.
How does the media’s focus on fear-inducing stories affect public perception?
It skews perceptions of risk by overemphasizing rare, dramatic events (e.g., shark attacks, mass shootings) while underreporting common, less sensational causes of death (e.g., heart disease, car accidents).
What is the impact of the media on perceptions of violent crime in the U.S.?
Despite violent crime rates declining since the 1970s, the media’s focus on isolated violent events leads most Americans to believe crime rates are rising.
How does survivor bias relate to media coverage of terrorism or mass shootings?
The media amplifies the visibility of dramatic, isolated events while neglecting widespread, less spectacular causes of death, creating a distorted view of risks.
What is an example of misaligned media coverage vs. actual risks?
Public mass shootings receive disproportionate media attention compared to car accidents, which cause vastly more deaths annually (less than 100 vs. 35,000).
How does the 24-hour news cycle amplify selection effects?
Continuous coverage emphasizes isolated, fear-inducing events, reinforcing public misconceptions about their frequency and importance.
What is an example of misaligned media coverage vs. actual risks?
Public mass shootings receive disproportionate media attention compared to car accidents, which cause vastly more deaths annually (less than 100 vs. 35,000).
How do our evolutionary instincts misjudge threats in modern life?
System 1 processes, evolved for small tribal communities, are overwhelmed by large-scale information networks, leading us to overreact to rare, dramatic threats and underestimate common risks.
What cognitive illusion is created by media-driven fear?
System 1 overreacts to dramatic events, while System 2 recognizes the statistical reality, causing a mismatch in perceived vs. actual risks.
How might proportional news coverage influence public behavior?
It could reduce fear of rare events and shift focus toward preventing major risks, like heart disease and cancer, through healthier lifestyle choices.
Why do stories about shark attacks elicit more fear than deer accidents?
Sharks are perceived as more dramatic and emotionally impactful, appealing to System 1, even though deer cause far more deaths annually.
What is media bias in the context of audience engagement?
Media outlets tailor content to engage their primary audience by emphasizing stories that align with their viewers’ interests, hopes, and fears, even if the stories are perfectly accurate.
How do tailored news and social media feeds contribute to political polarization?
By reinforcing pre-existing views and amplifying outrage toward opposing perspectives, creating echo chambers that limit exposure to conflicting ideas.
What is the echo chamber effect?
A situation where individuals are exposed only to information and opinions that reinforce their existing beliefs, preventing discovery of new or opposing perspectives.
Why is “checking news from the other side” insufficient to combat media bias?
It fails to address the deeper issue of tailored content and confirmation bias, which require a more rigorous effort to engage with the best arguments from opposing views.
What is publication bias in scientific research?
The tendency for journals to favor studies with surprising or engaging results, leading to underrepresentation of studies that confirm conventional wisdom.
What is the file drawer effect?
The tendency for researchers to avoid publishing studies with negative or “boring” results, leaving valuable data unshared and amplifying publication bias.
How does the file drawer effect impact the reliability of scientific evidence?
It skews the available evidence by excluding studies with negative results, potentially misleading researchers about the validity of a hypothesis.
How does pre-registration help combat publication bias?
By requiring researchers to announce their study protocols in advance, ensuring that all results, even unpublished or incomplete ones, are accounted for in the data pool.
What effect does media bias have on our perception of issue importance?
It magnifies certain issues that resonate with specific audiences while downplaying or ignoring others, skewing our sense of their actual prevalence or importance.
How does social media exacerbate confirmation bias?
Algorithms prioritize content that aligns with user preferences, making it more likely for individuals to encounter and share information that confirms their existing beliefs.
What problem arises when studies supporting surprising claims are published while others are not?
It creates a distorted view of the evidence, making the surprising claim appear more valid than it is.
What is the role of engagement-focused algorithms in news consumption?
They prioritize content that generates likes, shares, or emotional reactions, often reinforcing biases and amplifying polarization.
