RESEARCH METHODS CHAPTER 2 PSYCHOLOGY’S SCIENTIFIC METHOD.

RESEARCH METHODS

CHAPTER 2PSYCHOLOGY’S

SCIENTIFIC METHOD

4 GOALS OF PSYCHOLOGY

1) Describe behavior2) Predict behavior3) Explain behavior4) Control behavior

5 STEPS OF THE SCIENTIFIC METHOD

1. Observing some Phenomenon2. Formulating Hypotheses and

Predictions3. Testing through Empirical Research4. Drawing Conclusions5. Evaluating the Theory


1. Observing some Phenomenon• Asking questions• Variables

2. Formulating Hypotheses and Predictions


3. Testing through Empirical Research: Choose your research method Descriptive Research: describes some phenomenon

• Naturalistic Observation

• Survey/ Interview• Psychological/ Physiological Tests

• Case Study

• Archival ResearchCorrelational Research: shows relationshipsExperimental Research: shows cause and effect


3. Testing through Empirical Research: Choose your research design

(NOT for Experimental Research)Cross-sectional: Study participants of different age groups

at the same time.

• Advantage: quicker, less costly

• Disadvantage: cohort effects, sample variabilityLongitudinal: Study a particular group of participants over

a prolonged period of time.

• Advantage: more in-depth investigation, shows change over time

• Disadvantage: more costly, dropout/death


4. Drawing Conclusions• Replication• Descriptive/Inferential Statistics

5. Evaluating the Theory• Meta-analysis• Submitting results for publication

INTRODUCTORY TERMINOLOGY FOR SCIENTIFIC RESEARCH

•Variable: Any measurable condition that is controlled/observed in a study; anything that can change.

•Theory: A broad idea or set of closely related ideas that attempt to explain observations and to make predictions about future observations.

•Hypothesis: An educated guess that derives logically from a theory; a prediction that can be tested.

•Operational Definition: An objective description of how a variable is going to be measured and observed.

•Participants or subjects: The organisms whose behavior is systematically observed in a study.

RESEARCH METHODS

1. Descriptive Research: • Naturalistic Observation• Survey/Interview• Case Study• Archival Studies

NATURALISTIC OBSERVATION

Advantages Disadvantages• Realistic picture of

behavior• Good to start when little

is known about a phenomenon

• Difficult to remain unnoticed or unobtrusive

• Time consuming

Description: Observing the participant in their natural habitat without interaction

SURVEY/INTERVIEW

Advantages Disadvantages

• Gathers data of difficult to observe behaviors

• Large sample size• Cost effective• Relatively easy

• Wishful Thinking• Memory Lapses• Social Desirability Bias• Response Set• Wording Effect

Description: Use of questionnaires to gain insight on an individual’s attitudes or beliefs

CASE STUDY


• In-depth investigation• Helps formulate

theories• Unique cases

• Subjectivity • Researcher bias• Lack of generalizability

Description: An in-depth investigation on an individual or cohort (small group)

ARCHIVAL RESEARCH


• Researcher can not change data

• Cost effective

• Researchers have little to no control over information

• Credibility of sources

Description: Extracting evidence from original records or other researcher’s findings

RESEARCH METHODS

2. Correlational Research

CORRELATIONAL RESEARCH

• Research that examines the relationships between variables, whose purpose is to examine whether and how two variables change together.• There is NO manipulation of variables

• CANNOT imply a cause and effect relationship between the variables


CORRELATION DOES NOT EQUAL

CAUSATION!


• A local police chief in a small Midwestern town finds that as ice cream consumption increases, the crime rates increases. As people eat less ice cream, the crime rate decreases.

• The police chief concludes that ice cream causes crime.

• Scientists have linked television-watching with childhood obesity. According to a study in the Journal of the American Academy of Pediatrics, the degree of obesity rises 2 percent for each hour of television viewed per week by those aged 12 to 17.

• Scientists conclude that TV watching makes you obese.


• Third variable problem: The circumstance where a variable that has not been measured accounts for the relationship between two other variables.

CORRELATIONAL RESEARCH• Research study designed to determine the degree

to which two variables are related to one another• When two variables are related to each other,

they are co - related• A correlation is the numerical index of degree of

relationship• Correlation are expressed as a number between

0 and 1• Can be negative or positive (-1 to +1)

• Numbers closer to 1 (+ or -) indicate a stronger relationship



Correlation Coefficient: A statistical measure of the relationship between two variables.

How to read a Correlation Coefficient:


Strength


Direction


POSITIVE CORRELATIONS• As the value of one variable

increases (or decreases) so does the value of the other variable.

• The closer the correlation coefficient is to +1.0, the stronger the relationship.

• A perfect positive correlation is +1.0

• Direct relationship

0.5 1 1.5 2 2.5 3 3.50

0.5

1

1.5

2

2.5

3

3.5

Weight

Hei

ght


NEGATIVE CORRELATIONS• As the value of one variable

increases, the value of the other variable decreases.

• The closer the correlation coefficient is to -1.0, the stronger the relationship.

• A perfect negative correlation is -1.0

• Inverse relationship

0.5 1 1.5 2 2.5 3 3.5 4 4.5 50

0.51

1.52

2.53

3.54

4.5

Sweater Sales

Tem

pera

ture


ZERO CORRELATION• There is no relationship

whatsoever between the two variables.

• The closer the correlation coefficient is to 0, the weaker the relationship.

• No relationship

0 1 2 3 4 5 6 7 8 9 100

0.20.40.60.81

1.21.41.61.82

Kitten Perpetrated Homicides

Hou

rs S

pent

Bru

shin

g Te

eth

Coefficient of Determination: Percentage of variation in one variable that can be predicted based on the other variable.• Square the correlation coefficient by itself

• Ex:.70² = .70 * .70 = .49 = 49%.24² = .24 * .24 = .057 = 5.7%



Advantages Disadvantages• No manipulation of

variables• Allows large populations to

be studied at one time• Cost effective and Quick• Enables investigation of

difficult variables to study

• CANNOT show cause and effect

• Does not show the reason for the relationship

Description: determines the degree to which two variables are related to one another

RESEARCH METHODS CHAPTER 2 PSYCHOLOGY’S SCIENTIFIC METHOD.

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