Lecture 2

Ch. 1

Psychological Science

Class plan for today

1. Why do we need to use a scientific approach?

2. What does science value?

3. The Scientific Method

4. Experimental Designs

5. Correlation vs. Causation

6. In-class Activity 1

7. Research Ethics

Why do we need to use a scientific approach?

• Are intuition and common sense enough?

What characteristics are valued in scientists?

The Scientific Method

Methods for studying Psychology

• Be able to identify each method• Know the pros and cons for using each

method

Description

Case Study

Susan K

uklin/ Photo R

esearchers

Surveyhttp://w

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.lynnefeatherstone.org

Naturalistic Observation

Courtesy of G

ilda Morelli

Correlation

When one trait or behavior accompanies another, we say the two

correlate.

Correlation coefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = 0.37+

Correlation Coefficient is a statistical measure of the relationship between two

variables.

Positive Relationships

High

Low

GP

A

1-3 4-6 7-9Hours studying

Negative Relationships

High

Low

GP

A

Low Mod High

Alcohol Consumption

No relationship

Honesty

High

Low

SES

Low Mod High

Figure 5-5: A Perfect Positive Correlation

r = 1

Figure 5-6: A Perfect Negative Correlation

r = -1

Non-perfect correlation

-5

0

5

10

15

20

25

30

35

40

45

50

Sta

te a

nxie

ty

-.2 -.1 0 .1 .2 .3 .4 .5arcsin ave WM Unpl-neut

Bivariate ScattergramInclusion criteria: remove 917 from 062608setarcsin.svd

The relationship between being in a state of anxiety and performance on a memory task with emotional distracters

r=-0.326

Illusory Correlation

The perception of a relationship where no relationship actually exists. Parents conceive

children after adoption.

Confirming evidence

Disconfirming evidence

Do not

adopt

Disconfirming evidence

Confirming evidence

Adopt

Do not conceiveConceive

Michael N

ewm

an Jr./ Photo Edit

Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept

under (2) control.

Be able to identify the independent and dependent variables in examples of

studies.

Exploring Cause & Effect

Describing DataA meaningful description of data is

important in research. Misrepresentation may lead to incorrect conclusions.

Measures of Central Tendency

A Skewed Distribution

Measures of Variation

Range

Standard Deviation

Evaluating the results of a study

• What increases the chance that a difference between groups is a real, reliable effect?

Research Ethics

• Animal research

• Human research

In-class activity 1

• Get into groups of 2-4• Make sure you turn in the handout with all

your names on it