Admin: Reflection 1 due Friday

1) Recap Weber’s insights

2) Attributes of scientific evidence

3) Example

claim:

(For our purposes) a statement about what is true or valid.

• If you can add “is true” to the end or “it is true that” to the beginning of the statement without changing the meaning, it is a claim.

Don’t overthink this definition. It is as simple as it seems.

basis:

(For our purposes) the basis for a claim is the reason we should accept the truth or validity of that claim. It includes

• the evidence that is used to “prove” the claim is true

• and the assumptions required for the evidence to be valid “proof” (sometimes called the “warrant”)

colloquially, we refer to both parts as “evidence”

claim: “It rained last night”

basis: “I can see the street is wet”

What is the evidence?

What are the assumptions behind that evidence?

Science is distinct as a form of thought in that:

(1) Only certain claims can be investigated

(next week)

(2) Has special rules for using evidence and making assumptions to evaluate claims

today

Go to https://www.menti.com/fknajkidk8

Systematic use of evidence

Transparent procedures

Acknowledge uncertainty

Test claim against alternatives

How did you arrive at your conclusion?

• What data / observations did you use?
• What comparisons did you make?
• What choices as a researcher did you make, and why?

Why?

• Others can know the assumptions required to find result
• Others can challenge your choices/assumptions
• Others can replicate your work (objectivity)

Test claim against other competing claims

• Whichever claim “survives” many different tests is best

Why?

• Openness to being wrong (no assumption above challenge)
• Evidence consistent with different assumptions (objectivity)
• One piece of evidence can be consistent with many claims; Best claim generates most useful predictions

Observations we make:

• Clear rules for what we observe
• Clear rules for how we observe
• Clear rules for comparison
• Avoid “cherry-picking”

Why?

• Cherry picking assumes a truth, picks data to support it
• Systematic rules allows others to investigate for themselves
  • No “secret sauce”: (objectivity, enables challenging assumptions)

Limitations of finding:

• What questions remain unanswered after the study (what didn’t it tell us)?
• What assumptions were made that might not be true?

How certain or precise are the answers?

• Acknowledge possibility of results being driven by chance
• Acknowledge possibility of spurious relationships

Which of these four do you think is the most important part of scientific evidence?

A person’s prejudice against a group of people can be reduced through meaningful, interpersonal contact with a member of that group.

• This is the “contact hypothesis”, famously articulated by Allport (1954)

Does contact reduce prejudice?

Are efforts to change the minds of opponents same-sex marriage through a short conversation more successful when those conversations are with homosexuals (as compared to heterosexuals)?

Poll

2014 paper in Science:

Researchers conducted an experiment to answer this question:

about Transparent Procedures?