Together to Support a Cause

Why do we need experiments?

To test ideas, uncover how things work, and separate truth from guesswork

Why do experiments require controlled conditions?

To isolate cause-and-effect relationships and ensure that any observed results are due strictly to the variable being tested rather than outside factors

What is an independent variable?

Manipulated or controlled by the researcher

What is a dependent variable?

Is what the researcher measures

What is compared in a between-participants design? Why?

Different groups of participants assigned to different conditions

Compare results between two groups of participants

What is the difference between a control group and an experimental group?

Control does not get the experimental manipulation, while experimental does get it

What is compared in a within-participants design?

Same participants take part in all conditions

Compare results within the same group of participants

What is internal validity?

Extent to which we can draw accurate conclusions from our results

What is external validity?

Extent to which results apply to people generally

What are confounding factors? Give an example.

Keep groups/conditions as similar as possible

E.g., randomly assign participants to groups

How do you combat confounding factors? What does random assignment involve? Why do it?

Individual differences balance out at group level

Only effective when many people in each group

Do it to remove bias!

Why are participants’ motivations a concern?

Because it limits accuracy, increased bias

Why are participant’s expectations a concern? What is the placebo effect?

Because the outcome is affected if they know the study’s purpose

Do researchers' expectations matter? Explain.

Yes, they can affect the behavior of the participants

What is generalizability?

How well results apply to people outside of the experiment

What limits generalizability?

Artificial lab setting

Characteristics of the sample

Why use random selection? How is random selection different from random assignment?

Ensures that every member of a larger target population has an equal chance of being chosen for a study

Random assignment comes after, as a result of finding people THEN putting them into groups

Why is converging evidence important?

Relying on a single study is not enough to prove a claim, multiple studies strengthens the validity and reliability