The use of the scientific method in Psychology

A2 Psychology

Psychologists, like all scientists, use the Scientific Method to produce valid explanations of the world around them.

This method has both advantages and disadvantages.

Introduction

The Scientific process starts with observations of phenomena in the world.

In the Inductive Model this then leads to the developments of hypotheses.

Hypotheses are tested which may lead to new questions and new hypotheses.

Eventually such data may be used to construct a theory.

The Deductive Model theory construction at the beginning of the process, after making observations.

The Scientific Method

Scientific methodMake Observations

Theory

Life emerges from non-

living matter

Hypothesis

Mice emerge from dirty

socks

Experiment

Place dirty socks in a

glass jar for a few days

No mice!!!!

Reject the theory

Inductive process

Deductive process

Example: the spontaneous generation

theory

Referring back to the definition of ‘Scientific’, any research can be considered scientific as long as it collects data in an objective, controlled manner.

The following research methods have been put in order of how scientific they are considered to be.

Lab Experiments Field Experiments Natural Experiments Interviews/Questionnaires Observations

Scientific Method

The left picture is a burger from McDonalds. Or it is at least what you are led to expect you will get.

What about reality? You may think you know something but unless you test this

empirically you cannot know if it is true.

The right picture is the empirical evidence of what the burgers are really like.

Advantages – The Scientific Method is Empirical

So what is Empirical Data? Empirical data is information gained through direct

observation or experiment rather than reasoned argument or unfounded beliefs.

The Scientific aims to collect the facts.

Why is this an advantage? People can make claims about the truth of a theory or the

benefits of a treatment but the only way we know such things are true is through empirical evidence.

Advantages – The Scientific Method is Empirical

An important aspect of empirical data is that they are objective.

What does this mean?

That the data is not affected by the expectations of the researcher.

Systematic collection of measurable data is at the heart of the method.

Advantages – The Scientific Method is Objective

How would an experimenter allow for greater objectivity?

Usually via standardised procedures and instructions.

Why is this an advantage?

Without objectivity we have no way of being certain that data collected is valid.

Advantages – The Scientific Method is Objective

The aim of the Scientific Method is to test hypotheses by falsifying them.

i.e. rejecting a null hypothesis.

Why is this an advantage?

Because it is not possible to prove a hypothesis correct but you can prove it is wrong.

i.e. falsify it. “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”

Advantages – The Scientific Method is Falsifiable

The ideal form of the scientific method is a lab experiment because is enables the researcher causal relationships.

What is a causal relationship?

Showing cause and effect.

The experimental method is the only way to do this – where we vary one factor (independent variable) and

observe it’s effects on the a dependent variable.

Advantages – The Scientific Method is controlled.

In order for this to be a ‘fair test’ all other conditions must be controlled, and the best place for this is in a lab setting.

What are extraneous variables?

Any other variables apart from the IV that could in truth affect the DV.

Why is this an advantage? If we can’t demonstrate causal relationships then we can’t

be sure, for example, a person’s anxiety was reduced by the drug used.

Advantages – The Scientific Method is controlled.

Scientists record their methods and standardise them carefully so that the same procedures can be followed in the future.

i.e. replicated.

Why is this an advantage? Repeating a study is the most important way to

demonstrate the reliability and validity of an observation or experiment.

If the outcome is the same this affirms the truth of the original results.

Advantages – The Scientific Method permits replication.

In pairs You need to come up with as many advantages for each

study you can think of and relate the back to the advantages of the Scientific Approach.

Milgram’s (1963) study on Obedience. Asch’s (1951) study on Conformity. Selye’s (1935) study on Stress Loftus and Palmer’s (1974) study on Eyewitness Testimony. Gibson and Walk’s (1960) study of Depth Perception.

Over To You

Cause and Effect The Scientific Method lets us state that it is the IV causing

changes in the DV.

Quantitative Data This can be collected and then be analysed using

descriptive and inferential statistics tests, which can then be used to prove or disprove a hypothesis.

Participants With Scientific methods, especially lab experiments, you

can choose the participants that best represent your target population.

Other Advantages

Problems include:- Situational variables Participant variables Demand characteristics

Why is this a disadvantage? The observed effects may be due to

variables other than the IV.

Disadvantages –The scientific method may lack internal validity

Ecological validity is a problem when artificial settings are used.

Why is this a disadvantage? Findings cannot be generalised to the real

world phenomena

Disdvantages – The scientific method may lack external validity

Operationalised variables in experiments and behavioural categories in observations reduce the complexity of behaviour.

Why is this a disadvantage? Explanations of behaviour become over-

simplified.

Disadvantage – The scientific method can be reductionist

The nomothetic approaches looks to generalise findings to all people.

Why is this a disadvantage? Uniqueness and difference between

genders, cultures and ages are ignored.

Disadvantages – The scientific method may ignore individual differences

Experimental and observation methods often involve psychological harm and deception which is seen as necessary to maintain scientific rigour.

Why is this a disadvantage? Participants may be harmed Psychology could be brought into disrepute.

Disadvantages – The scientific method raises ethical issues

Investigator affects The scientific method does not acknowledge

that subjectivity of the researcher can affect the results.

Cultural/gender biases A necessity to be able to generalise

scientific findings means that they could be ethnocentric/androcentric.

Other disadvantages

Read through the example essays and highlight and identify the key advantages/disadvantages.

Highlight in a different colour where the person has used examples of research to support their arguments

Highlight in a different colour linking/signpost words used to give the essay good structure.

Example essays

Identify three things that you have learnt/found useful from reading these essays

Examples essays

You are going to complete an essay each by building on the points already made by others. This is how:-

Everyone write an introduction to the question:- Discuss the advantages of using the scientific

method in psychology (15) Write one point including one advantage, reason

why it’s good and an example -pass your essay on. Read the comments already written and write the

next point then pass it on. Do this until we have 5 points. Return the essays to the original writer and mark

them using the handout with the bubbles.

Collaborative essays