research meths

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RESEARCH

METHODS



AIMS && HYPOTHESES

The aim of a study is what you want to find out. When

writing a project it is important that this is very specific

A hypothesis states what your prediction is. There are

two types of hypotheses. A null hypothesis where you

state there will be no change. It is what you assume to

be true until you can prove otherwise. The alternativehypothesis is the prediction you (usually) are trying to

prove



This type of hypothesis is one which

predicts the direction of the difference or in

terms of correlational analysis predicts

either a positive or negative correlation

A directional hypothesis is also called a one

tailed hypothesis

A non directional hypothesis on the other

hand predicts a difference between twovariables but not the direction or in terms of

correlational analysis it does not predict

either a positive or negative correlation.

A non directional hypothesis is also called a

two tailed hypothesis



One-tailed hypothesis: a directional

hypothesis

Two-tailed hypothesis: One in which no

direction is predicted



EXPERIMENT

TYPES



LAB EXPERIMENTS

This type of experiment is conducted ina well-controlled environment not

necessarily a laboratory and therefore

accurate measurements are possible

The researcher decides where theexperiment will take place, at what

time, with which participants, in what

circumstances and using a standardised

procedure

Advantages

It is easier to replicate (i.e. copy) a laboratory

experiment

They allow for precise control of extraneous

and independent variables

They allow cause and effect relationships to

be established

Disadvantages

The artificiality of the setting may produce

unnatural behaviour that does not reflect real

life, and results cannot be generalised to the

population

Demand characteristics may bias the results

and become confounding variables



FIELD EXPERIMENTS

These are conducted in the everyday

(i.e. natural) environment of the

participants but the situations are still

artificially set up

The experimenter still manipulates

the IV, but in a real-life setting (so

cannot really control extraneous

variables)

Advantages

Behaviour in a field experiment is more likely

to reflect life real because of it natural setting,

i.e. higher ecological validity than a lab

experiment

There is less likelihood of demand

characteristics affecting the results, asparticipants may not know they are being

Disadvantages

There is less control over extraneous variables

that might bias the results. This in turn makes

the experiment harder to replicate

They may be more expensive and time

consuming than lab experiments



NATURAL EXPERIMENTS

Natural experiments are conducted in the

everyday (i.e. natural) environment of the

participants but here the experimenter has no

control over the IV as it occurs naturally in real

life, e.g. Hodges and Tizard's research (1989)which compared the long term development of

children who have been adopted, fostered or

returned to their mothers with a control group

of children who had spent all their lives in their

biological families

Advantages

Behaviour in a natural experiment is more likely

to reflect life real because of it natural setting,

i.e. very high ecological validity

There is less likelihood of demand

characteristics affecting the results, as

participants may not know they are being

studied

Can be used in situations in which it would beethically unacceptable to manipulate the

independent variable

Disadvantages

There is less control over extraneous variables

that might bias the results. This in turn makes

the experiment harder to replicate

They may be more expensive and time

consuming than lab experiments



Experiment: An investigation in which the independent

variable is manipulated (or changed) in order to cause a

change in the dependent variable. There are three types:

1. Lab study: This type of experiment is conducted in awell-controlled environment

2. Field study: Field experiments are done in the everyday

(i.e. natural) environment of the participants but the

situations are still artificially set && IV still manipulated

3. Natural study: Natural experiments are conducted in the

everyday (i.e. natural) environment of the participants but

here the experimenter has no control over the IV



OTHER

EXPERIMENTS



Disadvantages

It lacks generalisability to the rest of the population due t

a very small and unrepresentative sample.

No cause and effect can be legitimately established. Very difficult to replicate. Low reliability

Time Consuming and Expensive

Problems with a participants memory distortions when re

past events. Validity problems

More potential for observer bias due to the subjective nat

the method.

Can lead to subject attrition (Loss of Participants)

CASE STUDY

This method involves studying one individual or

one social group in detail

Case studies are often used when looking at

people who have gone through an unusual

experience or they are used when looking at

exceptional cases e.g. looking at an individual

with a rare mental disorder

It can be used to look at a broad range of traits

as opposed to a small number of traits that can

easily be looked at in a laboratory

Advantages

Highly detailed data is collected.

The data is high in Ecological Validity

It is often the only suitable method. E.g. Teaching a

Chimpanzee to speak. (Gardner and Gardner 1969)

It is the only suitable method when researching very

rare cases. E.g. a Case of Multiple Personality.

Thigpen and Cleckley (1954)



Correlation measures the relationship between 2 varia

Disadvantages

No cause and effect can be established. E.g. there

may be a positive correlation between caffeine

intake and stress scores, but the correlation does

not indicate that caffeine is causing the stress.

CORRELATION

Correlation measures the relationship between 2variables to see if there is a trend or a systematic

pattern

In Psychology the pairing of two variables would

usually be a particular individuals score in 2

variables

E.g Stress Score and Caffeine intake. Stress is not

determined by caffeine intake so there can be no

cause and effect from a correlation

Correlation can be plotted out on scatter grams

Advantages

Precise information about the degree of the

relationship can be established by the correlatio

coefficient

No manipulation of behaviour is required

Establishing a relationship between the 2 variabl

may imply that there could be a cause and effect

relationship. Further experimental research canconducted to establish cause and effect



QUESTIONAIRES

Often used to find out peoples opinions orbehaviours

They can be highly structured enabling

results to be easily analysed using

descriptive statistics

Questionnaires can be less structured

allowing the respondent to give further

details

Advantages

Questionnaires can be highly structured

enabling results to be easily analysed us

descriptive statistics.

Easy to analyse and quantify

Easy to replicate Easy to administer

Disadvantages

Lacks flexibility

People may give biased answers to create a

socially desirable response.



INTERVIEWS

This involves the researcher askingverbal questions to the participant

Interviews range from having no

structure e.g. just a topic area

established to being very structured

e.g. a list of pre-prepared questions

Advantages

Very Detailed

Very Flexible allowing the researcher

to explore interesting things that

may arise

Disadvantages

Very Time Consuming

Difficult to analyse and quantify

Potential for participants to give incorrect

responses



Psychologists carry out research using experimental and non-experimental

methods:

1. Experiments are more scientific, but they lack ecological validity

2. Questioning people can be a useful way to measure opinions

3. An interview would allow more depth than a questionnaire, but a

questionnaire is easier to administer

4. The observational method allows observations of naturally occurring

behaviour, The presence of an observer can change participants behaviour

5. Case Studies are used when more detail is required or when looking at an

unusual case. They are time consuming and lack generalisability

6. A correlation indicates whether there is a relationship between 2

variables, but it does not establish cause and effect



EXPERIMENTAL

DESIGNS



Different participants are used in each

condition of the independent variable. This

means that each condition of the experiment

includes a different group of participants.

This should be done by random allocation,

which ensures that each participant has an

equal chance of being assigned to one group

or the other

INDEPENDENT MEASURES Advantage Avoids order effects (such as practice or fatigue)

as people participate in one condition only. If a

person is involved in several conditions they man

become bored, tired and fed up by the time they

come to the second condition, or becoming wise

to the requirements of the experiment

Disadvantages

More people are needed than with the repeatedmeasures design (i.e. more time consuming)

Differences between participants in the groups

may affect results, for example; variations in age,

sex or social background. These differences are

known as participant variables (i.e. a type of

extraneous variable)



REPEATED MEASURES

The same participants take part in

each condition of the independent

variable. This means that each

condition of the experiment includes

the same group of participants

Disadvantages

There may be order effects. Order effects refer to

the order of the conditions having an effect on

the participants behaviour. Performance in the

second condition may be better because theparticipants know what to do (i.e. practice

effect). Or there performance might be worse in

the second condition because they are tired (i.e.

fatigue effect.

Advantage

Fewer people are needed as they

take part in all conditions (i.e. saves

time)



MATCHED PAIRS

One pair must be randomly

assigned to the experimental

group and the other to the

control group

Advantage

Reduces participant (i.e. extraneous) variables

because the researcher has tried to pair up the

participants so that each condition has people

with similar abilities and characteristics

Avoids order effects, and so counterbalancing is

not necessary

Disadvantages

Very time-consuming trying to

find closely matched pairs

Impossible to match people

exactly, unless identical twins!



Experimental design refers to how participants are

allocated to the different conditions (or IV groups) in an

experiment. There are three types:

1. Independent measures / groups: Different

participants are used in each condition of the

independent variable

2. Repeated measures: The same participants take part

in each condition of the independent variable

3. Matched pairs: Each condition uses different

participants, but they are matched in terms of certain

characteristics, e.g. sex, age, intelligence etc



Sampling

Type

Def inition Advantages

Disadvantages

Opportunity You use the first

people who fit your

criteria.

Easiest sampling method, very

inexpensive.

Doesn't use a variety of people

that represent the population.

Can be biased because only

people from your own social

group are included.

Systematic Take every 2nd

10th

etc.

person

Hopefully more

representatives, simple to do,

have no bias.

Because it is only based on

chance there is no way of

ensuring it is representative.

Random Everyone in the target

population has an

equal chance of being

selected.

Hopefully more representative

and has no bias.

Can be difficult to implement and

therefore expensive.

Stratif ied The proportions of

people in the sample

are equivalent to thepopulation (eg. 50%

female).

Very representative and

therefore the findings of an

experiment using this methodcan be applied to everybody

more easily.

Complicated to make a sample

that represents everybody so

could take a long time and beexpensive.



VARIABLES



Independent variable (IV):

Variable the experimenter

manipulates (i.e. changes)

assumed to have a direct effect

on the dependent variable

A variable is anything that can vary, i.e. changed or be

changed, such as memory, attention, time taken toperform a task etc

Variable are given a special names that only apply to

experimental investigations. One is called the dependant

variable (DV) and the other the independent variable (IV).In an experiment, the researcher is looking for the possible

effect on the dependant variable that might be caused by

changing the independent variable

Dependent variable (DV):

Variable the experimenter

measures, after making

changes to the IV that areassumed to affect the DV



IV = variable manipulated bythe experimenter

DV = variable measured by

the experimenter



Extraneous variables These are

all variables, which are not the

independent variable, but could affect

the results (e.g. DV) of the experiment.

Extraneous variables should becontrolled were possible. They might

be important enough to provide

alternative explanations for the effects

Confounding variables

These are variables that do

actually have an affect on the

DV. A confounding variable

could be an extraneous

variable that has not been

controlled

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