Textbook Notes (369,067)
Canada (162,366)
Psychology (9,699)
PSYB01H3 (581)
Chapter 6

Chapter 6 Notes 97-03.doc

4 Pages
89 Views

Department
Psychology
Course Code
PSYB01H3
Professor
David Nussbaum

This preview shows page 1. Sign up to view the full 4 pages of the document.
Description
PSYB01 Chapter 6 – True Experiments I - Merzenich and colleagues examined whether healthy participant aged 60 years or older would show improved mental abilities following brain plasticity training - Variables differ in the degree to which they can be controlled or manipulated - True Experiment: Researcher has complete control over manipulation of independent variable, standard approach to establish causality Basics of Experimentation - Researcher controls with whom, with what and how the study is conducted - Experimental Control: Holds constant as many extraneous variables as possible, if variable s are constant, they cannot account for results of experiment - Randomization: Procedures to counteract bias o Memorizing words (we remember first and last, primacy effect and recency effect), must move the words around so that the words aren’t gonna be in the same place o Random assignment: Each participant has an equal likelihood of being placed in either control or experimental groups (chance procedure) o Ex post facto: participants selected and grouped after the fact or on the basis of a particular characteristic - Independent Variables: something the researcher manipulates in some way in order to determine its effects on a dependent variable, often referred to as factors o Single-factor experiment: an experiment with only one independent variable o Multi-factorial designs: experiment with more than one independent variable o Condition/Treatment: a particular way in which participants are treated o Experimental group vs. comparison group vs. control group o Control group provides baseline against which the treatment can be compared - Dependent Variables: o Posttest: measurement of the outcome in both groups after the experimental group has received the treatment o Pretests: measure dependent variable prior to the experimental intervention o Using identical pre- and posttests is to be avoided because performance is likely to be influenced by practice of taking the same measure twice - Control Variables: Used to show that these factors do not explain results, if they do, the nthe results are considered to be confounded o Challenge in identifying or selecting which variables to be controlled for or held constant o Some variables are easy to keep constant: Time of day, temperature, instructions, etc. Research Design Alternatives PSYB01 Chapter 6 – True Experiments I - Between-Subjects Design: independent groups of participants receive different levels of independent variable o Same participants never receive all levels of independent variable : therefore, a large number of people are needed for study - Randomization and Matching o Ensure that there are as few differences as possible among participants in various treatment groups o Individual differences are equalized or neutralized when researchers use random assignment to form experimental and control groups o Must also have a pretest after randomization so that it is actually randomized o Randomized comparative change design/pretest-posttest control group design: Randomized experimental design with a pretest and posttest o Act of taking pretest may cause change o Randomization removes bias from assignment process but only by relying on chance which can result in some intergroup differences o Matching: pairing persons on the basis of similarity of gender, age, year in school or some other objective characteristic o Matched-pairs design: first match in pairs and then randomly assign one to experiment and one to control - Within-subjects Design: all research participants receive all levels of the independent variable o Repeated-measures, within-subjects design: when same participant is tested repeatedly over time, each participant serves as their own control o Fewer participants needed because they all receive the treatment o Longitudinal research design: collect data for decades, participants followed over lifespan and data are ordered in time so that they can be developmentally examined o Carryover effects: if performance in one condition affects performance in a subsequent condition o Randomization ensures that any differences in treatment orders are due to chance only - Counterbalancing: Technique to control for order of treatments that ensures that each treatment or level of the independent variable occurs in each time period of the experiment o As number of treatments/
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit