Class Starter # 5

What are the 3 types of research done by psychologists?

Myers’ PSYCHOLOGY

(7th Ed)

Chapter 1 Thinking Critically with Psychological Science

The Need for Psychological Science

Psychologists, like all scientists, use the scientific method to

construct theories that organize observations and imply testable hypotheses

The Need for Psychological Science

3 Broad Categories of Research

1) Experiments based on scientific method; “cause and effect”

2) Descriptive studies-case studies, surveys, & naturalistic observation

3) Correlation studies-look for a relationship between variables

The Need for Psychological Science

Theory an explanation using an integrated

set of principles that organizes and predicts observations

Hypothesis a testable prediction often implied by a theory

Experimentation

Experiment an investigator manipulates one or

more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable)

by random assignment of participants the experiment controls other relevant factors

Experimentation

Operational Definition a statement of procedures

(operations) used to define research variables

Example- intelligence may be operationally defined

as what an intelligence test measures

Experimentation Independent Variable

the experimental factor that is manipulated

the variable whose effect is being studied Dependent Variable

the experimental factor that may change in response to manipulations of the independent variable

in psychology it is usually a behavior or mental process

Experimentation

Random Assignmentassigning participants to experimental and control conditions by chance

minimizes pre-existing differences between those assigned to the different groups

Experimentation Placebo

an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent

Double-blind Procedure both the research participants and the

research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo

commonly used in drug-evaluation studies

Experimentation

Experimental Condition the condition of an experiment that

exposes participants to the treatment, that is, to one version of the independent variable

Control Condition the condition of an experiment that

contrasts with the experimental treatment serves as a comparison for evaluating the

effect of the treatment

Experimentation

Replication repeating the essence of a

research study to see whether the basic finding generalizes to other participants and circumstances

usually with different participants in different situations

Description

Psychologists describe behavior using case studies,

surveys, and naturalistic observation

Case Study

Psychologists study one or more individuals in great depth in the hope of revealing things true of us all

Ex. case study of Phineas Gage, railroad worker who was stabbed through the brain with a metal shaft.

Surveys

technique for ascertaining the self-reported attitudes or behaviors of people

usually by questioning a representative, random sample of people

Naturalistic Observation

observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

The Need for Psychological Science

Critical Thinking thinking that does

not blindly accept arguments and conclusions examines

assumptions discerns hidden

values evaluates evidence

Terms

Hindsight Bias we tend to believe, after learning an

outcome, that we would have foreseen it

the “I-knew-it-all-along” phenomenon Overconfidence

we tend to think we know more than we do

Terms

False Consensus Effect tendency to overestimate the extent

to which others share our beliefs and behaviors

Example Romantic relationships between people often start off with a glow as hormones and False Consensus overshadow real differences. However, the cloud-9 effect eventually wears off as the loving couple eventually discover that they are not, after all, that similar (and in fact often are amazingly incompatible!).

Terms

Illusory Correlation the perception of a

relationship where none exists

Correlation Correlation Coefficient

a statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other

Correlation coefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = +.37

Correlation

Scatterplot a graphed cluster of dots, each of which

represents the values of two variables the slope of the points suggests the

direction of the relationship the amount of scatter suggests the

strength of the correlation little scatter indicates high correlation

also called a scattergram or scatter diagram

Correlation

Perfect positivecorrelation (+1.00)

No relationship (0.00) Perfect negativecorrelation (-1.00)

Scatterplots, showing patterns of correlations

Correlation

Scatterplot of Height and Temperament

55 60 65 70 75 80 85

959085807570656055504540353025

Temperamentscores

Height in inches

CorrelationThree Possible Cause-Effect Relationships

(1)Low self-esteem

Depression

(2)Depression

Low self-esteem

Low self-esteem

Depression

(3)Distressing events

or biologicalpredisposition

could cause

could cause

could cause

or

or

and

Comparing Research Methods

Statistics Mode

the most frequently occurring score in a distribution

Mean the arithmetic average of a distribution obtained by adding the scores and then

dividing by the number of scores Median

the middle score in a distribution half the scores are above it and half are

below it

Statistical Reasoning

Range the difference between the highest and

lowest scores in a distribution Standard Deviation

a computed measure of how much scores vary around the mean

Statistical Significance a statistical statement of how likely it is that

an obtained result occurred by chance

Frequently Asked Questions about Psychology

Can laboratory experiments illuminate everyday life?

Frequently Asked Questions about Psychology

Does behavior depend on ones culture? Culture--the enduring

behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next

Frequently Asked Questions about Psychology

Does behavior vary with gender?

Frequently Asked Questions about Psychology

Why do psychologists study animals?

Is it ethical to experiment on animals?

Is it ethical to experiment on people?

Frequently Asked Questions about Psychology

Is psychology free of value judgments?