CHAPTER 4 – RESEARCH METHODS

Psychology 110

How Do We Know What We Know?

You can know something because a friend told you

You can know something because you read itYou can know something because it “seems

obvious” (i.e. common sense)You can know something because it “feels

right” (i.e. intuition)These ways of knowing may be right, but they

may also be wrong.Psychologists rely on the scientific method

because it is more likely to answer certain kinds of questions correctly.

The Scientific Method

A method of learning about the world through observation, experimentation and statistical analysis

Observation & Bias

Simplest scientific methodPotential for bias Most common bias = “confirmation bias,” a

tendency to search for information that confirms a preconception.

Participant bias = tendency for research participants to behave in a certain way because they know that they are being observed or they believe they know what the researcher wants

You can minimize these biases through naturalistic observation = observing/recording behavior without manipulating or controlling the situation

Case Study

A specific research technique that relies on observation

Study a single individual in depth in the hope of revealing universal principles

May or may not be possible to extend the findings to other people or situations

Researchers hope that they can gain important knowledge from case studies that can help explain general truths about human behavior

As similar case studies accumulate, researchers gain increasing confidence in the accuracy of their conclusions

Example Case Study - Genie

Discovered in California in 197013 years oldHad spent her life in such isolation that she

had not even learned to speakSince 1970 psychologists have intensively

studied Genie’s behavior and progress to learn about the development of language and social skills

***this would be considered a longitudinal case study

4. Correlations

Is there a relationship between two variables?Positive correlation – both variables increase

(or decrease together). People with higher income have more years education

Negative correlation – one variable increases while the other decreases. The more that babies are held the less that they cry.

Does not reveal a cause-and-effect relationship, just that there is a relationship between the two variables.

Useful for making predictions.

5. Surveys

Questions a sample of people to collect information about their attitudes or behaviors

InexpensiveBias can influence the wording of a question and

thus the resultsPopulation = the entire group of people about

which you would like to know something (Leo Hayes students)

Random sample = a sample that fairly represents the “population”

In general, larger, random (computer) samples are “better”

2. Experiments

Only way to show cause-and-effect A research method in which the researcher

manipulates and controls certain variables to observe the effect on the other variable

Because experiments require researchers to control the variables in a study, the chances of isolating the variable causing the particular effect are much greater

Continued – Hypothesis & Operational Definitions

Hypothesis = a testable prediction about the outcomes of research

Often starts out general but then gets more specific

Operational Definitions = attempt by researchers to clearly define the behaviors that they are looking for

Continued - Variables

Independent Variables (IV): The variable that should cause something to happen The variable that the researcher manipulates The variable that will cause a change in the

dependent variable

Dependent Variable (DV): The variable that should show the effect of changing

the IV The IV causes the DV to happen

Continued - Groups

Typically experiments have two groups – experimental and control

Experimental – exposed to the independent variable

Control – not exposed to the independent variable (function as a comparison group)

Usually at least 20 people in each groupShould be randomly chosen to avoid bias

Continued – Confounding Variables

“Other” variables (than the IV) that could affect the dependent variable

Environmental, expectationsEnvironmental – same temperature, lighting,

noiseExpectations – make sure that participants

are not aware of hypothesis (could alter their behavior)

Continued - Replication

Researchers should be able to replicate your exact experiment

New – Research Ethics

See handout