Psychological Research Strategies

Module 2

Why is Research Important?

Gives us a reliable, systematic way to consider our questions

Helps us to draw logical, supported conclusions

* Not all will conduct research, but all have to evaluate its relevance

Research Methods

Example research topic: Does listening to music through headphones affect

studying?

What does common sense say?

Observation

Benefit: simplest scientific technique Problem: bias Two Types of bias:

Researcher bias – observation may be influenced by what they want/expect to discover

Participant bias – may respond a certain way because: know they’re being observed believe they know what the

researcher wants

What do you see?

Ways to reduce bias:

Researcher – finding ways to rely less on observers’ opinion

Participant – using naturalistic observation – naturally occurring settings

Case Studies

one person is studied in depth in the hope of revealing universal principles

Problems: bias can’t always apply results of one study to other

situations

Sometimes necessary for ethical reasons

Correlational Study

Reveals the extent to which two variables are related to each other

Examples: Is there a relationship between… diet and health? training techniques and success in sports? studying and better grades?

Uses of Correlational Studies

does not prove that a cause-and-effect relationship exists

tell you onlyonly that variables are related, not why they are related

Useful for making predictions – the stronger the correlation, the more accurate your prediction will be

Correlation Positive Correlation – both variables

increase or decrease together Examples: height & weight, studying effectiveness

& frequency of wearing headphones

Perfect Positive Correlation Moderate Positive Correlation

Correlation Negative Correlation – one variable

increases while the other decreases Example: hours spent watching TV & GPA, studying

effectiveness & frequency of wearing headphones

Perfect Negative Correlation Moderate Negative Correlation

Surveys

Goal: discover the self-reported attitudes or behaviors of a sample of people using questionnaires or interviews

Benefits: efficient, can reach large crowds

Problems: bias in wording, social desirability

Surveys

For results to be relevant to the population: Random sample – every member of the

population has an equal chance of being selected

Adequate number of participants – determined by mathematical formulas; larger samples = more relevant results

Longitudinal and Cross-Sectional Studies both study how individuals change during life

Longitudinal studies – follow the same group of individuals for many years Benefits: abundant data Problems: expensive, difficult to conduct = rare

Cross-sectional studies – compare people of different ages at one time Benefits: more efficient Problems: changes in time can affect results

Experiments

Purpose: onlyonly method that allows you to establish a cause-and-effectcause-and-effect relationship

Hypotheses and Operational Definitions

1st step: form a hypothesis – testable prediction of the experiment’s outcome

operational definitions of the variables – putting them in a more specific form so they can be precisely measured

Operational Definitions Example

Which of these example hypotheses has provided operational definitions?

A) “Headphones influence concentration in class”

B) “Students assigned to wear headphones in class will have higher average grades at the end of the quarter than students banned from wearing headphones.”

* WS w/ partner

Independent and Dependent Variables

Two variables of a hypothesis:1. Independent variable (IV): the variable that should

cause something to happen

2. Dependent variable (DV): the variable that should show the effect (or outcome) of the IV

IV & DV Example “Students assigned to wear headphones in

class will have higher average grades at the end of the quarter than students banned from wearing headphones.”

What are the independent and dependent variables?

IV = presence or absence of headphones

DV = participants' average end-of-quarter grades

Groups & Random Assignment

Most experiments have two groups: Experimental group – exposed to the IV

(headphones) Control group – not exposed to the IV

(no headphones)

Critical feature: people placed in groups by

random assignment – assigning by chance

Confounding Variables

Variables other than the IV that could produce a change in the DV

Examples of individual differences for our example:

Confounding variables can be controlled for by random assignment – can assume that factors will balance out evenly across both groups

• amount of sleep• personal problems• health• quality of teachers

Control for Other Confounding Variables:Environmental Differences

Other types of confounding variables: Environmental differences Expectation effects

Control for environmental differences by making sure both environments are the same (temperature, lighting, noise conditions)

Control for Other Confounding Variables:Expectation Effects

Control for expectation effects by: Blind procedure - participants don’t know

hypothesis until after data is collected

Double-blind procedure – the people collecting the data & participants don’t know the expected outcome

Placebo – nonactive substance or condition that

is given instead of a drug or active agent (all drug studies)

Data Analysis

Run the experiment & collect the data, then analyze the numbers using statistics

Statistically significant – the possibility that the difference between groups would occur by chance alone is not more than 5%

Replication

Results must be replicable (can be reliably repeated) to prove a cause-and-effect relationship between the IV & DV

Ethics: Human Research

4 Ethical Principles Guiding Human Research:1. Informed consent – about nature of research & risks

2. Right to be protected from harm and discomfort

3. Right to confidentiality – can’t release data about individual participants

4. Right to debriefing – full explanation of research when involvement is done

Ethics: Animal Research

Must have clean housing, adequate ventilation, and appropriate food, be well-cared for