IS PSYCHOLOGY A

SCIENCE?

What is Psychology?

The Science of Psychology

What Psychologists Do

Critical and Scientific Thinking in Psychology

Descriptive Studies: Establishing the Facts

Correlational Studies: Looking for Relationships

The Experiment: Establishing Causes

Evaluating the Findings

IS PSYCHOLOGY A

SCIENCE ?

Defining Psychology

Psychology is a discipline concerned with the

study of behaviour and mental processes

and

how they are affected by an organism's:

physical state,

mental state,

and external environment

Scientific psychology has four

basic goals:

to describe

to explain

to predict

to change behaviour and mental

processes

HOW DO WE KNOW WHAT

WE THINK WE KNOW

IS TRUE?

Bordens and Abbott (2008)

Three types of explanation of human behaviour

Common sense Belief based Pseudoscience

Experience Religion Presented as scientific

but not

Intuition Political Vague

Not tested Personal Not reproducible

Consistent with a

framework of beliefs

Minimal evidence in

support of claims

Can we trust our common sense?

Do you think the following are true?

Birds of a feather

flock together

Absence makes the

heart grow fonder

Two heads are

better than one

Action speak louder

than words

Opposite attract

Out of sight, out of

mind

Too many cooks

spoil the broth

The pen is mightier

that the sword

Psychology is common sense

We learn and remember best

when we study intensively

over a concentrated period

Advertisers often use

subliminal persuasion to

influence our behaviour.

Punishment is the most

effective way to permanently

change behaviour

The more people present at

an emergency, the more likely

it is that at least one of them

will help.

Eyewitness testimony is the most

reliable kind of evidence

Most people use only about 10%

of their brain capacity

All people with dyslexia see words

backward (tac-cat)

In general, it’s better to express

anger than to hold it in.

The lie detector (polygraph) test is

90-95 % accurate at detecting

falsehoods.

People tend to be romantically

attracted to individuals who are

opposite to them in personality

and attitude

Well actually….

None of these statements are true, even if you

think they make sense.

In fact…..(see next slide)

Beliefs and intuitions

The idea that our beliefs and intuitions, are enough to answer questions about human nature is false.

Beliefs and intuition may help us to know what questions to ask, but they are not free from mistakes

We cannot rely on intuitions alone…….

Hindsight bias

The tendency to believe, after learning about

an outcome, that we would have foreseen it.

HINDSIGHT BIAS

When drilling the Deepwater

Horizon oil well in 2010, oil

industry employees took some

shortcuts and ignored some

warning signs, without

intending to harm any people,

the environment, or their

company’s reputation.

After the resulting Gulf oil spill,

with the benefit of 20/20

hindsight, the foolishness of

those judgments became

obvious.

Tendency to believe, after

learning an outcome, that

we could have predicted it.

Also known as the

I-knew-it-all-along

phenomenon.

Did We Know It All Along?

Hindsight Bias

Overconfidence in judgements

We may think we know more than we actually do (occurs in both academic and social behaviour)

How long do you think it would take to unscramble these anagrams?

People said it would take about 10 seconds, yet on average they took about 3 minutes (Goranson, 1978).

Anagrams

BARGE GRABE

ENTRY ETYRN

WATER WREAT

Psychology, Pseudoscience, and

Common Sense

Scientific Psychology bears little relationship to "Pop" Psychology

Fortune telling, numerology, graphology, and astrology are not part of psychology

Psychology is not just a fancy name for common sense

Psychological research often produces findings that contradict popular beliefs

CRITICAL AND

SCIENTIFIC THINKING IN

PSYCHOLOGY

Critical Thinking

Critical Thinking: The ability and willingness to

assess claims and make objective judgments

on the basis of well-supported reasons and

evidence, rather than emotion or anecdote

Critical Thinking Guidelines

Ask Questions: Be willing to wonder

Define Your Terms

Examine the Evidence

Analyze Assumptions and Biases

Avoid Emotional Reasoning

Don't Oversimplify

Consider Other Interpretations

Tolerate Uncertainty

What is science?

• Body of systematic knowledge that covers

general truths, principles and laws.

• Knowledge is found and tested using ‘scientific

methods’ – systematic process designed to

obtain objective information.

• Based on observable phenomena not opinion

What are the characteristics of a

scientific approach?

Must :

have a unified paradigm (a model for how to proceed)

use a scientific process for devising theories and testing hypotheses

test hypotheses empirically (experimentally)

be replicable and valid (discussed later)

generate findings that are generalizable and applicable to be of some use.

The role of paradigms

• A paradigm is a shared set of assumptions about the subject matter of the discipline and the methods used to study it.

• Kuhn (1996) claimed that psychology does not have a unifying paradigm – many different ones used e.g. • Psychoanalytic

• Behavioural

• Cognitive

• Neuro-biological

• Revolutions in thinking can cause a paradigm shift

• Many different paradigm shifts have already taken place in psychology

Paradigms change

Psychology is a

science

Science does not

develop continuously

and smoothly

Kuhn suggests that

this happens through

paradigm shifts

Paradigm shift

Unconscious

Drives

Urges

Introspection

Environment

Stimuli

Experiences

Empiricism

From psychoanalysis To behaviourism

Theory A theory is an explanation that integrates and organizes

principles and observations and predicts behaviour or events

A hypothesis is a testable prediction, arising from the theory, which enables us to accept, reject or revise the theory

An operational definition is a carefully worded statement of the exact procedures (operations) used in a research study

A replication is repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

The Scientific Method: how do theories advance

psychological science?

Theory

An organized system of assumptions and

principles that tries to explain a specified set of

phenomena and their interrelationships.

Principle of Falsifiability

The principle that a scientific theory must make

predictions that are specific enough to allow the

possibility that the theory can be shown to be untrue;

that is, the theory must predict not only what will

happen, but also what will not happen.

Principle of falsifiability & Freud

According to this principle Freudian „theory” is NOT a real „theory, because it can never be proved to be false.

Predictions in Freudian „theory” are very „woolly” and untestable

If something does not fit the theory, Freudians merely expand the theory to make it fit. They never reject any ideas which do not fit.

Freudian „theory” is not a theory because it cannot be tested to verify if it is true.

The Scientific Method: Constructing

Theories

Hypothesis

A statement that attempts to predict or to account for a

set of phenomena; scientific hypotheses specify

relationships among events or variables and are

empirically tested allowing the theory to be accepted,

rejected or revised.

Induction and Deduction Scientists use logic to

induce and deduce valid

conclusions

Induction

Moving from data to a

general theory of concept

Specific to general

Deduction

Moving from a theory to

particular statements

concerning data

General to specific

Data

Theory

Induction Deduction

The scientific process – Theory

construction and hypothesis testing

Observations Observations

Testable hypothesis

Conduct a study to test the hypothesis

Draw conclusions

Propose theory

Propose theory

Testable hypothesis

Conduct a study to test the hypothesis

Draw conclusions

Induction Deduction

Hypothetico-deductive method

Karl Popper (1935) – Philosopher of Science:

to be properly scientific, theories need to be stated first

and these should be used to generate expectations or

hypotheses which are capable of being falsified.

Falsification is the only way to be certain – as Popper

pointed out:

‘No amount of observations of white swans can allow the

inference that all swans are white, but the observation of a

single black swan is sufficient to refute that conclusion’

Hypothetico-deductive method

Identify a problem

Develop a hypothesis –

predictable and testable

Devise a study to

test the hypothesis

Analyse and

evaluate the results

Modify and repeat the

process

Develop a theory

Empirical Evidence

Evidence gathered by careful observation,

experimentation and measurement.

Empirical Testing

• Empiricism is the idea that knowledge is based on ‘direct experience’ and experimentation

• arguments, beliefs, ideas, hearsay, faith or superstition, however rational or logical, will not reveal true knowledge

• Experimental science – testing ideas - is the paradigm for gaining real knowledge

• Testing can be repeated to see if findings are the same – replication.

• Methods used must be objective.

Operationalizing concepts

In order to test hypotheses it is necessary to operationalise the concepts we are interested in, e.g.

How are we going to measure: Intelligence

Personality

Emotions

Memory

Does behaviourism (classical conditioning and operant conditioning) do this?

Operational Definition

A precise definition of a

term in a hypothesis,

which specifies the

operations for observing

and measuring the

process or phenomenon

being measured.

What makes Psychology less objective ….and

therefore less scientific?

• Confirmation bias

• Researcher bias

• Publisher bias

• Demand characteristics

• Cultural bias

• We cannot stand outside of human nature to

study it – we are it !!

• ‘Only the shallow know themselves’

Our bias to “prove” what we think we know

Confirmation bias Positive test bias or hypothesis confirmation bias

Snyder and Swann (1978)

• Interview person

Is he/she introvert/extrovert?

Given list of Qs to ask

some about being introverted (in what situation do you wish

you could be more outgoing?)

some about being extroverted (what would you do to liven

up a party?)

0

1

2

3

4

5

6

7

8

Extraversion Hypo Introversion Hypo

Extraversion

questions

Introversion

questions

Neutral questions

Confirmation bias

Causing people to act the way you expect

Word, Zanna & Cooper (1974) study

White interviewees perform “better”

White interviewers behave differently towards white and black interviewees

Trained interviewers to use “White” or “Black” style

White interviewees who get “White” style do better

Which cards did you turn over?

The answer was (b)

Only this option allows us to test the rule

properly – we need to try to falsify the rule and

not to confirm it.

Only turning A & 7 allow us to do this.

Vowels are the letters: A, E, I, O, U

See example below

Hypothesis Testing

Wason Selection task

If a card has a vowel on one side, then it has

an even number on the other side

E T 4 7

E T 4 7 2 A 5 U

Hypothesis Testing

Wason Selection task

If a card has a vowel on one side, then it has

an even number on the other side

E T 4 7 2 A 5 U

Hypothesis Testing

Wason Selection task

If a card has a vowel on one side, then it has

an even number on the other side

To check….

Watch video

https://www.youtube.com/watch?v=5NyAy8ux

Hio

https://www.youtube.com/watch?v=t7NE7apn-

PA

DESCRIPTIVE STUDIES:

HOW DO WE OBSERVE

AND DESCRIBE

BEHAVIOUR?

Testing hypothesis and refining theories using

Descriptive methods

Correlational methods

Experimental methods

To think critically, we need to understand these

methods and know what conclusions they will

allow.

The Scientific Method

How do psychologists use case studies, surveys

and naturalistic observations to observe

behaviour? Why is random sampling important?

Descriptive research is a systematic, objective

observation of people (as well as animals).

The goal when studying people is to provide a clear, accurate picture of behaviours, thoughts and attributes.

Methods used:

Case studies

Surveys and interviews

Naturalistic observations

The Scientific Method: Description

• Many cases in less depth; self-reported

• Wording effect

• Random sampling

• Utilizes random sampling of population for best results

The Survey

• Records behaviour in natural environment

• Describes but does not explain behaviour

• Can be revealing

Naturalistic Observation

• Examines one individual or group in depth

• Provides fruitful ideas

• Cannot be used to generalize

The Case Study

The Scientific Method: Description

Description is the starting point of any science

Research methods - the case study:

a technique in which one person is studied in

depth to reveal underlying behavioural principles.

Little Albert Experiment – James Watson

Research methods – the survey

http

://ww

w.ly

nnefeath

erstone.o

rg

Survey – random sampling

If each member of a population has an equal

chance of inclusion into a sample, it is called a

random sample (unbiased).

If the survey sample is biased, its results are not

valid. The fastest way to know about the marble colour

ratio is to blindly transfer a few into a smaller jar and

count them.

Survey: advantages, disadvantages

& problems

Can ask about things which people may not want to disclose to a researcher or that are unlikely to be observed

Free from interviewer bias

Low cost, easy data collection

Large samples, results generalisable

Only effective with educated & coperative respondents

May have a selection bias

Poor response rates

Responses may be „polite” or designed to „please” researchers or dishonest

Difficult to provide anonymity

Difficult to have control over/ slow to get results

Wording can affect results

Advantages Disadvantages

Research methods - Naturalistic Observation

Involves observing and recording human and animal behaviour in a real world setting

The researcher makes no attempt to interact with or change the behaviour of the people or animals observed.

Important because results of controlled laboratory studies often differ from those conducted in real-life. Remember that these descriptive

methods do not explain behaviour.

This illustrates how, without knowing anyone’s identity, big

data enable researchers to study human behaviour on a

massive scale.

NATURALISTIC OBSERVATION: TWITTER

MESSAGE MOODS, BY TIME AND BY DAY

Problems with bias

Problems with bias

Application and Generalisation

To apply psychological research we have to be able to generalise it to a wider population than our sample of participants.

Can psychology claim to be a

science?

• Scientific research is desirable

• Psychology shares the goals of all sciences, but does using the scientific method turn psychology into a science?

• Miller claims it is ‘dressing up’ – pseudoscience

• Kuhn claims it cannot be a science as it has no single paradigm unlike other sciences. A paradigm is a set of shared assumptions, in psychology there are a number of different paradigms or approaches to explaining behaviour.

• Can behaviour be measured objectively? Both experimenter bias and demand characteristics compromise validity. But Heisenberg found that you cannot even measure a subatomic particle without altering its behaviour (uncertainty principle).

• Psychology does explore issues like obedience in experiments where common-sense predictions are wrong.

Objections to the scientific

approach in psychology

Cannot measure people in the same way as

physical phenomena.

Study people in unnatural conditions

Control, isolation of variables not possible in

people

Ignores subjectivity of behaviour, superficial

Objectivity impossible, past experiences,

beliefs and ideas influence behaviour

What are the problems with a

scientific approach?

The scientific approach is reductionist, simplifying complex phenomena and theories down to basics.

Science is also determinist in its search for causal relationships, i.e. if X determines Y.

Science makes generalisations about people on the basis of data gained from samples not entire populations. Some psychologists argue that an individual approach is more suitable when treating patients.

Qualitative (descriptive rather than numerical) research is seen as less than scientific but triangulation can make this method more objective.

Also qualitative researchers must be reflective about their influence on their own research.

UNDERSTANDING

DATA

Reliability

Reliability is about consistency.

Reliability can also be thought of as the

extent to which data can be reproduced...

Reliable measures mean the same data

would have been obtained under similar

circumstances on another occasion

There are different types of reliability (see

next slide)

Four types of reliability

Threats to reliability

Bias in the data collection instrument is a

primary threat to reliability and can be

reduced by repeated testing and revision of

the instrument.

You cannot have a valid instrument if it is not

reliable.

Validity

Research is valid if it really measures what it is supposed to be measuring

Valid data is relevant data

This means that if we are trying to measure a construct such as concentration and we are trying to count the number of times someone looked away from their work, we should not be including the times they looked away because someone else attracted their attention e.g. by calling their name.

Types of validity

CORRELATIONAL

STUDIES: LOOKING FOR

RELATIONSHIPS

Correlation

Correlation: A measure of how strongly two

variables are related to one another

Variables: Characteristics of behaviour or

experience that can be measured or described

by a numeric scale

Correlation

When one trait or behaviour appears in a regular

relationship with another, we say the two correlate.

Correlation

coefficient

Indicates direction

of relationship

(positive or negative)

Indicates strength

of relationship

(0.00 to 1.00)

r = 0.37 +

Correlation coefficient is a statistical measure of the relationship

between two variables.

Correlation Studies

Correlation: A statistical measure of a

relationship.

A measure of how two or more variables are

linked together in an orderly way.

An indication of how one of the variables

predicts the other variable(s).

Positive Correlation:

An increase in one variable corresponds to an

increase in the other.

0

5

10

15

20

25

30

35

Grades 0 1 2 3 4

Act Scores

Negative Correlation

An increase in one variable corresponds to a

decrease in the other.

0

10

20

30

40

50

60

70

80

0 1 2 3 4

Parties

A scatterplot is a graph comprised

of points that are generated by

values of two variables.

The slope of the points shows the

direction, while the amount of

scatter depicts the strength of the

relationship.

Scatterplots of data

No relationship (0.00)

A weak correlation,

indicating little

relationship, has a

coefficient near zero.

Perfect negative

correlation (-1.00)

If 2 sets of scores relate

inversely (one set going

up as the other goes

down), the correlation is

negative. (Example:

toothbrushing & decay)

Scatterplots

Perfect positive

correlation (+1.00)

If 2 sets of scores tend to

rise or fall together, the

correlation is positive.

(Example: height & weight)

Note: Perfect correlations rarely

occur in the “real world”

Data Data showing height and temperament in people:

Is there a positive correlation, negative correlation, or little-to-no correlation?

Scatterplot of data from previous table The Scatterplot below shows the relationship between height and

temperament in people.

Coefficient of Correlation

Correlation: an observation that two variables (traits or attributes) are related to each other. The numbers that represent the strength and direction of a correlation.

Correlation coefficient: a statistical measure of how closely two things vary together, or how well you can predict a change in one from observing a change in the other

Positive correlation (above 0 to +1.00) Indicates a direct relationship, meaning that as one variable

increases, the other increases or both may decrease together

Negative correlation (below 0 to −1.00) Indicates an inverse relationship: As one thing increases, the

other decreases.

Zero correlation (0 to very low) Indicates no relationship

Prediction

The closer the coefficient is to 1 in either

direction, the stronger (more predictive) the

relationship

-.79 is a stronger relationship than +.34

or

Correlation and Causation Correlation does not mean causation!

Correlation is NOT causation

Just because two variables are related to each other

does not necessarily mean one causes the other.

EXPERIMENTAL

STUDIES

The search for causes

Do laboratory experiments help us to understand everyday life?

Purpose of experiments

Controlled, artificial environments are created in laboratory experiments to test general theoretical principles, not re-create exact everyday life behaviours

Resulting principles

Help explain everyday behaviour through resulting general principles, not specific findings

Psychological science

Focuses on seeking general principles that help explain many behaviours and less on particular behaviour

The Scientific Method:

Predicting Real Behaviour

Research Process

People low in self-esteem are more likely to report depression than

are those high in self-esteem. One possible explanation of this

negative correlation is that a bad self-image causes depressed

feelings. But, as the diagram indicates, other cause-effect

relationships are possible.

THREE POSSIBLE CAUSE-EFFECT RELATIONSHIPS

The Experiment

Defined by:

Control of variables (the things you want to

measure)

Manipulation of variables

Experimentation:

As in other sciences, experimentation is the backbone of psychological research.

Experiments isolate causes and their effects.

Exploring Cause and Effect

Experiments

Experiment: A controlled test of a hypothesis in

which the researcher manipulates one variable

to discover its effect on another.

How do experiments help to isolate cause and

effect?

Experiments: researchers focus on the possible

effects of one or more factors by

Manipulating the factors of interest to determine their

effects and

Holding constant (controlling) other factors.

They do so by randomly assigning people to:

An experimental group, in which people receive the

treatment,

A contrasting control group, whose members do not

receive treatment.

The Scientific Method: Experimentation

Experimental Design

Hypothesis: Nicotine in cigarettes impairs driving.

All conditions kept the same for both groups except nicotine.

Control condition is given placebo (inactive) cigarettes

Number of collisions is measured.

The Scientific Method: Types of Experimental

Procedure

Blind (uninformed) procedure: participants unaware of treatment

Double-blind procedure: participants and experimenter are unaware of treatment

Neither those in the study nor those collecting the data know which group is receiving the treatment.

Treatment’s actual effects can be separated from potential placebo effect.

Placebo effect: effect involves results caused by expectations alone.

Evaluating Therapies

When drug therapies are

evaluated, patients and

experimenters should

remain unaware of which

patients had the real

treatment and which

patients had the placebo

treatment (control group).

Double-blind Procedure

Experimental Variables

Independent Variable: A variable that an experimenter manipulates.

Dependent Variable:

A variable that an experimenter predicts will be affected by manipulations of the independent variable.

• Factor that is measured; the variable that may change when the independent variable is manipulated

Dependent variable in an experiment

• Factor other than the independent variable that might produce an effect

Confounding variable in an experiment

• Factor that is manipulated; the variable whose effect is being studied

Independent variable in an experiment

Variables

Experimentation: Independent and

Dependent Variables

Exploring Cause & Effect

Many factors influence our behaviour.

Experiments (1) manipulate factors of interest, while other factors are kept under (2) control.

Effects generated by manipulated factors isolate cause and effect relationships.

For example: the effects of bottle feeding vs. breast-feeding on intelligence

vs.

Independent Variable (IV)

An independent variable is a factor manipulated by the experimenter. The effect of the independent

variable is the focus of the study.

For example, when examining the effects of breast feeding upon

intelligence, breast feeding is the independent variable.

Dependent Variable (DV)

A dependent variable is a factor that may change in response to an independent variable.

In psychology, it is usually a behaviour or a mental process.

For example, in the study on the effect of breast feeding upon intelligence, intelligence is the dependent variable.

Experiment

A summary of steps during experimentation (effects of

bottle feeding vs. breast-feeding on intelligence.)

Look for the DV first when identifying variables in a study. Ask yourself, “What is the researcher trying to measure or look for in this study?”

Look for the IV second when identifying variables in a study. Ask yourself, “What are the researchers manipulating in order to determine its effects on the DV in this study?”

IV & DV

Confounding Variables:

Something that was not predicted or accounted for in designing/conducting the experiment that confused the relationship between the independent and dependent variables.

The Hawthorne Effect

The APA “Internet Isolation” study

Advantages of experimental work:

Establishes cause and effect relationships

Reduces or eliminates alternative explanations

Self-correcting through Replication

Limitations of experimental work:

Efforts to control may create very artificial

settings that may not validly reflect nature

EVALUATING THE

FINDINGS

Statistics:

The language used in science to communicate

the results of research

A tool used to determine if observed

differences are real and did not simply happen

by chance

Types of Statistics:

Descriptive

Inferential

Why Psychologists Use Statistics

Descriptive Statistics: Organize and

summarize data

Inferential Statistics: Assess how meaningful

results are, such as differences between

groups.

Significance tests assess how likely it is that a

study’s results occurred merely by chance

Descriptive Statistics:

Different ways of

describing and

summarizing data

collected in an

experiment.

They are used to express

how the observations

were alike or different for

different groups

Inferential statistics

Methods for drawing and

measuring the reliability

of conclusions about a

population based on

information from a sample

of the population

Used for hypothesis

testing

Making predictions

Assess reltionships

between variables

Statistical Reasoning

Statistical procedures analyze and interpret data

allowing us to see what the unaided eye misses.

Composition of ethnicity in urban locales

Descriptive statistics

“What’s the typical score (observation) in a

group of scores (observations)?

Specific statistics:

Mean

Mode

Median

Measures of Central Tendency

Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together.

Mode: The most frequently occurring score in a distribution.

Median: The middle score in a rank-ordered distribution.

The Mean

The arithmetic average

Add up all the scores and divide by the number of scores

5

4

3

2

1

__

15 / 5 = 3

Problems with the mean:

Easily influenced by the addition of a few extreme score

5 20

4 4

3 3

2 2

1 1

__ ___

15/5 = 3 30/5 = 6

The Median:

The middle score in a distribution of scores

5

4

3

2

1

The Mode:

The most frequently occurring score in a distribution of scores

6

5

4

4

3

2

1

Range:

The gap between the highest and the lowest

scores.

high score = 80 minus the low score = 20 means

the Range = 60.

Normal Curve – Gaussian distribution

A symmetrical, bell-shaped curve that describes the

distribution of many types of data (normal distribution).

Most scores fall near the mean.

The Standard Deviation:

A numerical way to describe how scores are

distributed above and below the mean

Gives the ability to express the distribution

visually

Standard Deviation

Measures of Central Tendency

A Skewed Distribution

Measures of Variation

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.

INFERENTIAL STATISTICS

Answers the questions

“Could the differences between two groups have

been caused by chance?”

and

“How confident can we be that we are right?”

When is a Difference Significant?

When sample averages are reliable and the difference

between them is relatively large, we say the difference has

statistical significance. It is probably not due to chance

variation

Use statistical tests: t-test, ANOVA, etc

Significance is stated as a probability figure

Psychology generally uses the .05 level as standard (95%)

although some research is reported at the .1 (90%) or .01

(99%) level

Significance is not about the importance of a difference, but

that the difference is big enough to matter and not caused by

some accidental difference between the groups

From the Laboratory to the Real

World

Choosing the Best Explanation

Sometimes there are competing explanations for

the same events

Judging the Result’s Importance

Statistical significance does not prove that a

result is important, only that it is reliable

Meta-analysis combines and analyzes data from

many studies

Advantages and Limitations of

Experiments

Experiments allow conclusions about cause-effect relationships.

Participants in experiments are not always representative of larger population.

Much psychology research is carried out using colleges students as participants.

Field Research: Descriptive or experimental research conducted in a natural setting outside the laboratory.

Research

Method Basic Purpose How Conducted

What Is

Manipulated Weaknesses

Descriptive To observe and

record behavior

Do case studies,

naturalistic

observations, or

surveys

Nothing

No control of

variables; single

cases may be

misleading

Correlational

To detect

naturally

occurring

relationships; to

assess how well

one variable

predicts another

Collect data on

two or more

variables; no

manipulation

Nothing Cannot specify cause

and effect

Experimental To explore cause

and effect

Manipulate one or

more factors; use

random

assignment

The

independent

variable(s)

Sometimes not

feasible; results may

not generalize to

other contexts; not

ethical to manipulate

certain variables

Comparing Research Methods

Illusory Correlation: A perceived, but nonexistent, correlation.

Illusory correlations can help explain many superstitious beliefs, such as the presumption that infertile couple who

adopt become more likely to conceive.

Confirming

evidence

Disconfirming

evidence

Do not

adopt

Disconfirming

evidence

Confirming

evidence Adopt

Do not

conceive Conceive

Mich

ael New

man Jr./ P

ho

to E

dit

Order in Random Events

“With a large enough sample, any outrageous thing is likely to

happen.” ~Diaconis and Mosteller

An event that happens to but one in 1 billion people every day

occurs about 6 times a day – 2000 times a year.

Angelo and Maria

Gallina won two

California lottery

games on the same

day.

Jerr

y T

elfe

r/ S

an F

ranci

sco C

hro

nic

le

During the 2010 World Cup, a

German octopus selected the box

with the right national flag,

correctly predicting (eight out of

eight times) the outcomes of

Germany’s matches and Spain’s

final win. Random or remarkable?

People perceive patterns to make sense of their world.

Even in random, unrelated data people often find order, because random sequences often do not look random.

The Need for Psychological Science:

Perceiving Order in Random Events