Chapter 2Psychological Methods

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Chapter 2: Section 1Conducting Research

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Main Objective:• List AND explain the steps

scientists follow in conducting scientific research.

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STEPS IN SCIENTIFIC RESEARCH1. Form a question (posing a question based on

experience, psychological theory or common knowledge)

Question: What effect does temperature have on aggressive behavior?

* Construct: Cannot be seen or measured

Example: aggression is experienced by everyone, but it can’t be seen or measured directly.

Therefore…research questions are best directed toward behaviorBehavior observed in field observations or laboratory

Section 1: Conducting Research

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After asking a research Question:

2. Form a hypothesis (making an educated guess). Worded

in an “If” / “Then” statement.

EX: If people are exposed to a hot environment then their aggressive behavior increases.

3. Test the hypothesis (examining the evidence through any of a variety of means)

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4. Analyze Results (looking for patterns or relationships in the evidence)…you ask what findings mean.

5. Draw a conclusion (determining whether the findings support the hypothesis and adjusting it if they do not)

(known as validation)

Section 1: Conducting Research

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Replication:• For the findings of a study to be confirmed, the

study must be replicated the study must be repeated– and it must produce the same results as before.

• Might use a different set of participants who differ in age, gender, socio-economic background, etc.

Section 2

Surveys, Samples, and Populations

Survey Method• Asked to respond to a series of questions about a particular subject

• Gathering information by directly asking people

• Questionnaires

• Oral interviews

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Activity:

Favorite Musicians

Half of the class anonymously write down your three favoritemusicians

Half of the class answer surveyor’s questions

Analysis:

1. Compare results about preferred shows between the two halves of the class.

2. Compile lists of the artists that each half claimed to like.

Question…

Analysis:

Are people more willing to admit liking certainartists if their responses are anonymous?

If so, why might this be?

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Problems With Surveys?

• People might not be honest

• Some worry responses won’t be kept confidential and only reveal what they want to reveal

• Might try to please (tell questioner what they think they want to hear

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Population and Samples

What to consider when conducting research?

1. What group or groups of people to study?

2. How will they be selected?

Example: survey on whether a vote will raise the driving age to 18

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Target Population

The whole group you want to study or describe

• Example: all possible voters on a referendum

• Doesn’t include non-voters

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Samples• Not practical to target all the voters in Pennsylvania…

instead:

• Researchers study a sample

• A cross-section as similar as possible to the target population

6Representative Sample• Example: a large number of people who represent all the voters in Pennsylvania

• Could then reasonably predict the outcome of the referendum by interviewing a sample this large

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Random Sample• Just like it sounds; individuals are selected by chance from the target population

• Each member of the target population has an equal chance of being chosen

• If the random sample is big enough, chances are it will accurately represent the whole population

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Stratified Sample• Sub-groups are represented proportionately

• Example: African Americans make up 12% of population so 12% of sample should be African American

• A large enough random sample is likely to be stratified even if you don’t take steps to make sure it is

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Generalizing Results• Researchers are cautious about generalizing their findings to groups other than those from which their samples were drawn

Example: if researchers found that men prefer certain types of cars, they couldn’t

conclude that women prefer those same types of cars if women weren't

included in the study

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Volunteer Bias• People who volunteer to participate in studies may

bring with them a volunteer bias

Volunteers:

• May be more willing to disclose personal information

• May be more interested in research than those who

don’t volunteer

• May have more spare time to participate in research

activities than other people

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All of these factors could slant the results in a particular direction

Section 3

Using Observation for Research

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Methods of Observation

The Testing Method• Psychologists often use tests to learn about human

behavior• Intelligence • Aptitude • Vocational • Personality

humanmetrics.com/cgi-win/jtypes2.asp

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The Case-Study Method

• In-depth investigation of an individual or a small group

• Psychologists may observe people being studied, speak directly with them, interview others who know them

Genie, feral children, etc.

Case of H.M. : short termand long term memory

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The Longitudinal Method• Researchers select a group of participants and then observe them over a long period of time (years, even decades)

• Enables researchers to see how people change over time

• Time consuming and expensive

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Cross-Sectional Method• Researchers compare differences and similarities among people in different age groups at a given time

• Instead of following a set of individuals over a number of years, researchers select a sample that includes people of different ages

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Naturalistic-Observational Method• Researchers observe the behavior of people or animals in their natural habitats

• Enables researchers to witness the behavior of people or animals in their natural setting

• Disadvantage? No control of setting or events.

Naturalistic-Observational Method

1. Determine a workable research question.

Example: What is the average size of the group in which people congregate during lunch?

Does it vary according to the gender of its members?

2. Make and record your observations.

3. Report your findings to the class.

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Laboratory-Observation Method

• Participants are observed in a laboratory setting

• Enables researchers to precisely control certain aspects of the study

• Disadvantage? Labs cant duplicate real-life environments.

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Analyzing the Observations

How do psychologists analyze and interpret results?

One method is correlation or the measure of how closelyone thing is related to another

Positive Correlation: as one goes up, the other goes up

example: study time and grades(people who study more earn higher grades)

Negative Correlation: as one goes up, the other goes down

example: relationship between stress and health (students’

stress increases ability to fight off colds decreases)

Correlation describes relationships, but doesn’t always reveal cause and effect

Section 4

Experimental and Ethical Issues

The Experimental Method1

Method used to answer questions about cause and effect

Drawback: conditions in an experiment don’t always reflect conditions in real life

video clip: Milgram Experiment

Independent Variables

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Variables: factors that can vary or change

In an experiment, the independent variable is the factor thatresearchers manipulate so they can determine effect

Example: warm temperatures cause aggression in humans

Dependent Variables3

dependent variable depends on something---the independent variable

Example: researchers want to find out if the level of aggression depends on temperature

Experimental and Control Groups

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Ideal experiments use experimental and control groups.

Members of an experimental group receive the treatment,members of a control group do not. Participants are randomly assigned to one group or another.

All other conditions (except the treatment) are the same for both groups

Makes it possible for researchers to conclude that the experiment’s results are caused by the treatment, not something else

The Placebo Effect5

A placebo is a substance or treatment that no effect apart from aperson’s belief in its effect

Does psychotherapy work? video clip

Single and Double-Blind Studies6

Q. How can researchers avoid the influence of expectations and the placebo effect?

A. By keeping participants unaware of, or blind to, the treatment

they are receiving.

In a single-blind study, participants don’t know whether they are in the experimental group or the control group

Double-Blind Studies7

A study in which both participants and researchers are unaware whoreceives the treatment is called a double-blind study

Participants assigned at random to have a real drug or a placebo

Neither the people taking the medicine or the people measuring the results are aware of who’s taking what

Central Tendency and Dispersion

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Researchers organize data to make generalizations about that data

Central tendency is a number that describes the average score of a distribution of numbers

Mean, median, and mode are all measures of central tendency

Standard deviation is the measure of the distance of every scoreTo the mean (average)

Large range = higher standard deviationSmall range = lower standard deviation

Ethical Issues9

Ethics are standards for proper and responsible behavior

Research with People: Confidentiality: records of research participants are kept private

Informed Consent: agree to participate only after being informed about possible negative effects and given a choice

Deception: may be used only when benefits outweigh harm

Ethics in Using Data: must be willing to discard their hypothesis in light of the evidence

Ethical Issues10

Research with Animals

most research isn’t harmful to animals, but psychologists and scientists do sometimes carry out research that is harmful to animals

video clip