Week 3 Lecture Methods of Psychological Research Flashcards
What are two essential characteristics of Experiment-based research?
- Manipulate one variable and measure whether the variable produces changes in another variable, when compared to no manipulation.
- Random assignment of participants to conditions
What are the variables in experimental research?
Independent and dependent
what is the dependent variable?
- Measured by experimenter and influenced by the independent variable
Which variable is cause and which variable is a effect?
- cause: independant
- effect: dependant
What is the independent variable?
The variable that is manipulated by the experimenter
What is a key aspect we need to control for in a true experiment?
We want to control for anything else that could different between the two tasks so anything other than the variable that we are going to manipulate
What Is the difference between random assignment and random sampling?
Random sampling is how we are going to choose the participants who will be involved in the study from the full population. In contrast random assignment is what happens after we already have our study sample
What are the two basic experimental designs?
- Between groups (or between subjects) design
- Within subjects (or repeated measures) design
What does the between groups experimental design consist of?
- Each group is composed of different people
- Important that people in each group are equalon factors that could influence the manipulation
- Random Assigment
different people test each condition, so that each person is only exposed to a single user interface
What is random assignment used for?
- Control for potential differences between group
- Each participant chosen for the study has equal chances of being put into either group
What are the two groups in experimental design study?
Experimental group and control group
What does the within groups experimental design consist of?
- same participants in all conditions of the study
- Individuals in each condition are equal, because they are the same people
- counterbalancing
What is counterbalancing used for?
- to control for the order of the manipulation
- so the order of condition 1 and condition 2 will be altered in different participants.
What is quasi-experimental design?
- Independant variable s manipulated
- BUT participants are not randomly assigned to groups or conditions - gender, age-group
What is a drawback of the within groups experimental design?
the effects of the order of the conditions which is dealth with through counterbalancing
What axis is the dependant variable on a graph?
y-axis
What axis is the independant variable on a graph?
x-axis
What are multiple independant variables?
- When two or more independant variable are manipulated at the same time.
- Must interpret main effects versus interaction effects of the manipulation
What is a main effect?
the effect of an independent variable on a dependent variable averaged across the levels of any other independent variables
What is an interaction effect?
the simultaneous effect of two or more independent variables on at least one dependent variable in which their joint effect is significantly greater (or significantly less) than the sum of the parts.
What is the experimental group?
Receives the manipulation/ treatment
What is the control group?
- not exposed to manipulation or treatment
- basis for comparison
Why is a control group important?
allows researchers to compare the way things are in the presence of an independent variable with the way things would have been in the absence of an independent variable.
What should the control group closely resemble?
the control group should closely resemble the experimental condition in order to rule out other variables that could explain the findings.
