Research Methods

Revision

Investigation Design

• Aim– What the experimenter wants to investigate.

• Hypotheses– Directional – the predicted difference in two

conditions (one-tailed).– Non-directional – predicts there is a difference,

without stating the direction (two-tailed).– Null – there will be no difference between conditions.

• IV– Manipulated by the researcher.

• DV– Measured by the researcher, this is the effects of the

IV.

ScenariosAre the following

hypotheses directional or non-directional?

1. Boys score differently on aggressiveness tests than girls.

2. Students who have a computer at home do better in exams than those that don’t.

3. Participants remember the words that are early in a list better than words which appear later.

4. Hamsters are better pets than budgies.

5. Words presented in a phonemic for are recalled differently to those presented in a semantic form.

Directional

Non-directional

Writing hypotheses

• A good hypothesis should start: “there will be...”– Non-directional continues “...a difference”

• Can you write both directional, non-directional and null hypotheses for each of the following studies.1. A study to find out whether boys or girls

watch more television.2. A study to see if teachers give higher marks

to more or less attractive students.3. A study to see if amount of sleep affects

schoolwork.

Sampling

Opportunity SamplePeople are asked to take part, e.g. on a street, in a

supermarket etc.

Weaknesses:Biased due to small

population drawn from.

Strengths:Easiest method.

Quick.Convenient.

Volunteer SampleParticipants apply via

adverts to take part in the study.

Weaknesses:Highly motivated sample.

May not be representative of target population.

Strengths:Convenient.

No bias from the experimenter.

Random SampleParticipants are drawn

from a hat, or by using a random computer generator method.

Weaknesses:Biased samples can occur

(e.g. more boys than girls).

Strengths:Unbiased as everyone has an

equal chance of being selected.

Experimental Method

Laboratory Experimentstake place in a laboratory

(a controlled environment) and the

researcher manipulates the IV.

Weaknesses:Lacks mundane realism.

Behaviour may change as people know they are

being watched.

Strengths:Can control extraneous

variables.Easily replicated.

Field Experimentstake place in the

participants’ natural environment and the

researcher manipulates the IV.

Weaknesses:More difficult to control

extraneous variables.Ethical issues of being

watched without knowing.

Strengths:Natural environment.

Higher mundane realism.

Natural Experimentstake place in the

participants’ natural environment the

researcher does not manipulate the IV.

Weaknesses:Extraneous variables are

common.Cannot determine cause and effect due to no IV.

Strengths:Allows research where

the IV cannot be manipulated.High validity.

Yarmey (1993)

Challenge Time

• Pick up the red cards from the pack.• Place them into three categories:

– Lab experiments– Field experiments– Natural experiments

• Then decide if they are random, volunteer or opportunity samples.

• Place them on the grid.

Pilot Studies

• A small-scale trial run of the research before the real study takes place.

• Reasons for a pilot study:– Check that there are no flaws in the study;– Check the participants understand the

instructions and what they are required to do;

– Ask a few participants about their experience of taking part; and

– Changes can then be made to the procedure if necessary, to avoid wasting time/money.

Experimental DesignIndependent Groups

DesignParticipants only take

part in one condition of the experiment (2 separate groups)

Weaknesses:More ppts are needed than repeated measures design.

Differences between participants in the groups

may affect results, (participant variables).

Strengths:Avoids order effects.

Less demand characteristics

Matched Pairs DesignParticipants are matched

in each condition for characteristics that may have an effect on their performance. e.g. age,

gender, IQ etc.

Weaknesses:Very time-consuming trying

to find closely matched pairs. Impossible to match people

exactly. Requires more participants.

Strengths:Reduces participant

variables. Avoids order effects.

Repeated Measures Design

Participants take part in both conditions of the experiment (1 group).

Weaknesses:Order effects are more likely to occur (counterbalancing

needed).Demand characteristics more

likely as participants might guess the aim of the study.

Strengths:Avoids the problem of participant variables.

Fewer people are needed.

PicturesWords

1 1 1

11

2

2 2 2

2

PicturesWords

When one variable increases so does the other variable

When one variable increases the other variable decreases

Correlational Analysis

• Shows the relationship between two variables.• Each individual has two scores (one on the X axis

and one on the y axis.• The scattergraphs of results look like this:• A statistical test can be used to work out if the

relationship is significant.• The results are as follows:• Strengths:

– Can be used when other research is unethical or impossible. If correlation is significant further research is justified.

• Weaknesses:– Misinterpretation of cause and effect is possible. There

may be other intervening variables that cause the change.

0No

correlation

-1 perfect negative

correlation

+1 perfect positive

correlation

Weak Weak Strong Strong

We calculate a coefficient between -1 and +1

The closer to 1 (+ or -) the stronger the relationship

Mini-Whiteboard Challenge

• Guiseppe Gelate always liked statistics at school and now he has his own ice cream business he keep various records. The table below shows his data:

• Sketch a scattergram of Guiseppe’s data.• What can you conclude from the data in the scattergram?• What intervening variable might better explain the

relationship between ice cream and aggression?• Describe how you would design a study to show Guiseppe

that ice cream does (or does not) cause aggressive behaviour.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ice cream sales 10 8 7 21 32 56 130 141 84 32 11 6

Aggressive crimes 21 32 29 35 44 55 111 129 99 36 22 25

0 20 40 60 80 100 120 140 1600

20406080

100120140

A graph to show the relationship be-tween ice cream sales and aggressive

behaviour

Ice cream sales

Agg

ress

ive

Crim

es

Observations

Controlled Observations

The behaviour being observed is under

controlled conditions, e.g. in a lab. An example

of this is the strange situation.

Structured Observation

Observations are organised using

behavioural categories (e.g. behaviours you might expect) and

sampling procedures (e.g. event and time

sampling).

Unstructured Observations

The observer records all relevant behaviour

without using a system. This might be used if the

behaviour is unpredictable.

Covert Observations

One-way mirrors may be used in a lab. This is so that the participants’ behaviour doesn’t

change if they know they are being watched.

Overt Observations

The researcher is open about what they are studying and they are in the room where

the behaviour is being observed.

ChallengeMost observation questions are linked to attachment. Can you answer this question?A psychologist wanted to investigate the effects of age of adoption on aggressive behaviour. He compared children who had been adopted before the age of two with children who had been adopted after the age of two. The children were observed in their school playground when they were six years old.a) Suggest two operationalised behavioural categories the psychologist could use in

his observation of aggressive behaviour. Explain how the psychologist could have carried out this observation.

Behavioural Category 1:Behavioural Category 2:Explanation of how the observation could have been carried out (4)

b) Explain one ethical issue the psychologist would have needed to consider when carrying out this research. How could the psychologist have dealt with this issue? (4)

The psychologist wanted to investigate how aggressive the children were when they were at home. He interviewed a sample of their parents to investigate this.

c) Explain why using interviews might be better than using questionnaires in this situation. (4)

Naturalistic Observations

Naturalistic Observations

An observation in a natural setting where the

researcher does not interfere in any way. A

structured observation is likely to be used.

Advantages DisadvantagesGives a realistic view of behaviour.Can be used as a preliminary investigation.More valid than interviews/questionnaires.

No control over EVs (except in a lab).Observer bias may occur.Ethical issues if you don’t know you’re being watched.

Designing Observations

You may need:• a behavioural checklist (a system where a behaviour is ticked every time it is seen); • a rating system (where the observer rates someone, e.g. 1-5 in terms of their attractiveness); or • a coding system (where each expected behaviour is given a number and every behaviour seen is written down).

Self-Report Methods

QuestionnairesA list of standardised set of questions is given to each

respondent; they give their answers in writing:

• Closed questions• Open questions

Weaknesses:Social desirability bias.

Sample may be biased as only certain people are

willing to take part.

Strengths:Easily repeated.

Cheap and quick.

InterviewsQuestions are asked orally .

Structured interviews: predetermined questions.Unstructured interviews:

questions are developed as a response to the answers

given.

Weaknesses:Interviewer bias can occur.

Reliability of using the same interviewer.

Strengths:Easily repeated with

standardised questions.More detailed responses can

be probed.

How to design them…

Good questionnaires have:•Clear questions.•Filler questions to distract the respondent from the purpose of the study.•Easy questions at the start.•A technique to collect respondents.•Pilot study to test the questions.

Interviews and questionnaires must:•Be checked for reliability (split-half/test-retest).•Be valid (a representative sample and have face validity).•Have no ethical issues.

Case Studies

• The study of a single person in detail.• Information comes from a range of

sources (diary, interviews, observations, family etc).

• They are generally longitudinal.Advantages Disadvantages

Rich data is collected.Can be used to investigate rare human behaviour.

Difficult to generalise.Unreliability when recalling past events.Researchers may lack objectivity.Issues of confidentiality.

Extraneous Variables

Age

Intelligence

Motivation

Experience Gender

Order effects

Time of day

Temperature Noise

Investigator effects

Demand characteristics

If extraneous variables are not controlled and they

cause a change in the DV then they become

confounding variables. Researchers must control all

EVs.

Spot the EVs

• Two classes of primary school children are tested to see if older or younger children have better memories. One class contains older children, the other class contains younger children. The children are tested in their own classrooms by their own teacher.

• Some students investigate whether men or women are more affected by alcohol. They give each participant a reaction time test and then give them two glasses of wine, followed by another reaction time test.

• A psychological study tested the effects of vitamins on exam performance. Participants were told beforehand that the vitamins enhanced exam performance. One group of participants received a vitamin pill and the other group received a placebo. The exam performance of the two groups was measured.

Reliability and Validity

• Making sure the study is correct and has no design faults ensures high internal validity. There should be no EVs.

Internal Validity

• When you can generalise the results from one study to another you say the study has high external validity. Three types (historical, ecological, population).

External Validity

• When the coding system, or observational checklist is consistent and you record the same result you can say that your study has high internal reliability.

Internal Reliability

• When the items you measure are consistent over time, you can say that the measure has high external reliability.

External Reliability

BPS Code of Ethics

Informed Consent

Tell the participants what will happen in the study so they can make an informed decision about whether to take

part. But sometimes the participants could guess the true aim and change their behaviour.

The researcher asks for consent in writing and gives just some information to participants. Debrief after the study

(tell aims and their role in study) can also withdraw.

Deception

Sometimes we have to hide the true aims of the study. But there is a difference between withholding

information and being false. Fully informed consent has not been given.

Debrief is vital. Presumptive consent can also be gained (ask similar people to the participants whether they

would agree to take part). Ethical committee can also be used to discuss the study.

Right to Withdraw

All participants can leave the study at any point, especially if they feel they have been deceived. This can bias the

results for the researcher if the participants who remain are more obedient.

Participants can leave whenever they feel uncomfortable, they will be told this in the initial briefing. Money or

rewards will still be paid.

Protection from harm

Participants should not experience any negative physical or psychological effects (e.g.

physical injury or lowered self-esteem). Should remain in the state they arrived.

Avoid any risks that are greater than everyday life. The researcher should stop the study if

any harm looks likely to occur.

Confidentiality

A person's personal information should be protected. The Data Protection Act makes this a legal right. Anonymity may be guaranteed.

Ask for written consent for personal information to be stored (securely). No names

should be recorded, instead false names or numbers are used

Privacy

A person’s right to control the flow of information about themselves. People do not

expect to be observed in their own home, while they might if they were in the park.

It is acceptable to observe in situations where you may normally overhear others (e.g. shopping centre). If privacy is invaded,

confidentiality should be kept.

What is so unethical?!The Stanford Prison study by Zimbardo

(1971) took great care to inform the prospective participants about what

would be involved in the study. However, the participants who were selected to be the prisoners were not

informed that they would be arrested in their own homes, and thus did not

know the amount of distress that would be caused by participating.

Craik and Lockhart (1972) conducted a study on memory where participants

had to read 30 questions and for each of the questions wither respond ‘yes’ or

‘no’. Afterwards they were asked to recall as many words as they could. They were not informed of the true aims of the study (to compare deep

with shallow processing) and were not told that they would have to recall the

words.

Middlemist et al. (1976) investigated invasion of personal space by

conducting a field experiment in a men’s urinal. There were three

conditions: a confederate (ally of the researcher) stands either immediately next to a participant, one urinal away

or absent. An observer records onset of micturation times (how long it took to

urinate) as an indication of how comfortable the participant felt.

Milgram’s study involved paying participants $4.50 to take part in a

study about the effects of punishment on learning (although they were told it

was a study on memory). The were told they could leave at any time

(although there were a series of prods by the experimenter to encourage continuation). 3 participants had

seizures as a result of taking part in the study.

Presentation of Quantitative Data

A table to show the results of memory (self-rated) and a score on a standard memory test.

Scattergraph

Line graph Bar chart

Table

Graphs should be simple.They should have a short, but informative, title.

The x axis should be labelled (usually the IV).The y axis should be labelled (usually the DV).

Only the scattergraph is a

good example of what to do.

Avoid doing wrong what the

other graphs are.

Past Paper Question

• Two groups of patients took part in a trial to compare the effectiveness of two different drug therapies. One of the groups was given Drug A and the other group was given Drug B. All patients completed a rating scale at the start of a ten-week course of treatment and again at the end of the course. This scale measured the severity of symptoms.

• The Drug A group had an average score of 9 before the therapy and an average score of 4 at the end of the course.

• The Drug B group had an average score of 7 before the therapy and an average score of 5 at the end of the course.

• Sketch and label a bar chart to illustrate the data. (4 marks)

Analyse this graph• Some research has suggested that there is a relationship between the time children

spend in day care and their aggressive behaviour. Researchers selected a group of school children who had been in day care. They asked the children’s mothers to estimate how many hours a week their children had spent in day care. They measured the same children’s aggression.

• Relationship between average hours spent in a day care and aggression

• (a)     How many children are represented in this scattergram? (1 mark)• (b)     Suggest one way in which the children’s aggression could be measured. (2

marks)

Measures of Central Tendency and Dispersion

MeanAdd all the numbers up in the data set and divide by the number of numbers.

Weaknesses:Can hide extreme values.

Cannot be used with nominal data (categories).

Strengths:Makes use of all values in the

data set.

ModeThe most common value in

the data set.

Weaknesses:There can be several modes.

Strengths:Useful for nominal data.

MedianWhen the numbers are

ordered, this is the middle number.

Weaknesses:Not as sensitive as the mean

as not all numbers are considered.

Strengths:Not affected by extreme

scores.

RangeThe difference between the highest and lowest

numbers in a data set.

Weaknesses: Strengths:Affected by extreme values. Easy to calculate.

Standard DeviationThe average spread of data around the mean (a

low standard deviation indicates reliability).

Weaknesses: Strengths:May hide extreme values. More precise.

Practice Questions• For each of the following data sets calculate:

a) Meanb) Modec) Mediand) Range

• Why is it better to know the standard deviation than the range?

• A psychologist has conducted an experiment to see how long it takes people to offer help when someone falls down. The results are shown below.

• State one conclusion that can be drawn from:a) The mean response timesb) The range of each set of scoresc) The standard deviations of each set of scores

Victim appears to be drunk Victim has a cane

Mean response time 24.9 seconds 19.7 seconds

Range of scores 10-48 10-30

Standard deviation 11.7 6.8

1) 2, 3, 5, 6, 6, 9, 12, 15, 21, 222) 2, 3, 8, 10, 11, 13, 13, 14, 14, 293) 2, 2, 4, 5, 5, 5, 7, 7, 8, 8, 8, 10

Presentation of Qualitative Data

• Content analysis is a research tool used to indirectly observe the presence of certain words, images or concepts within the media (e.g. advertisements, books films etc.).

• First the psychologist decides what to analyse (e.g. a diary).

• Researchers then count and analyse the presence, meanings and relationships of words and concepts. These form codes.

• Codes with similar content are compared, and then grouped into categories.

• Similar categories can be grouped together into larger units.

• Conclusions can be drawn.

Quantitative and Qualitative Data

Type of data Advantages Disadvantages

Quantitative

•Easier to analyse

•Can be summarised into graphs

•Can draw neat conclusions due to numerical data

•Oversimplifies human experience into numbers

Qualitative

•Represents how complex human behaviour is

•Gains access into human thoughts

•Provides rich details

•More difficult to detect patterns and draw conclusions

•Subjective analysis can occur due to personal expectations and beliefs