2. Designing Psychological Investigations

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Designing Psychological Investigations

Learning Objectives (See specification outline at beginning of booklet) Be able to describe the different types of research methods used in psychology,

and evaluate each according to their strengths and weaknesses Be able to select, apply and design appropriate research methods for a given

research question Be able to describe, evaluate, apply and design appropriate sampling methods Be able to describe, evaluate and apply methods for ensuring reliability and

validity in psychological research. Be able to describe, evaluate and apply ethical considerations in the design and

conduct of psychological investigations.

Examination questions – see handoutThese come under section C of the PSYA4 examination. 35 marks are awarded for this section – it is assumed that you will spend 40% of your time answering this section, because marks are worth 40% of the total marks. The reason for this is to highlight the importance of research methods in Psychology, and to make sure you do not get a high grade without having learned significant research methods understanding and skills.

In order for you to be able to fulfill the learning objectives (and therefore answer the examination questions), we will design, carry out, evaluate and write up 4 pieces of research – one from each main research method. We will do this after revising research methods from PSYA1. After this we will move onto the analysis of data, and after each piece of research has been completed we analyse the results using descriptive and inferential statistics.

Please have your research methods booklet and hand-outs from PSYA1

REVIEW OF RESEARCH METHODSEXPERIMENTS

Experiments try to establish cause and effect relationships. There are three main types - laboratory, field and natural (or quasi) experiments. The best experiments are ones which manipulate the IV and measure the effect this has on the DV. A causal relationship can only be established if all other extraneous variables are controlled. For this reason, the majority of experiments are conducted in lab environments.

Complete the table below to identify a definition, strengths and weaknesses of each experimental method:

Definition Strengths Weaknesses

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Lab Experiment:

Field Experiment:

Natural Experiment:

Experimental Design

Once the researcher has chosen the experimental method which best suits the nature of the study, they then have to choose what type of design it will have. The choices are repeated measures, independent groups and matched pairs.

Now fill in the table below, and answer the questions that follow:

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Experimental Design: definition

Strengths Weaknesses Research example

Repeated measures:

Independent Groups:

Matched Pairs:

What are order effects?

How can researchers reduce them?

What is counterbalancing?

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What is a control group and why are they used?

EXTRANEOUS VARIABLESSituational Variables

Participant Variables

Participant Effects

Investigator Effects

Demand Characteristics

How are all these possible confounding variables are controlled?HYPOTHESES

Null hypothesis

Experimental (Alternate) Hypothesis

Directional (One tailed)

Non-directional (Two tailed)

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Operationalisation of variables

Independent Variable

Dependent Variable

RELIABILITY

VALIDITYINTERNAL VALIDITY

What can lower the internal validity?

EXTERNAL VALIDITY (AS TB p 69)Ecological Validity

Population Validity6

Historical Validity

Improving External Validity:

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Correlations

Correlations are designed to investigate the strength of a relationship between two variables. The strength of this correlation is expressed by the correlation coefficient. The correlation coefficient is always between +1 and -1 where +1 represents a perfect positive correlation and -1 represents a perfect negative correlation. A correlation coefficient of 0 means that there is no correlation between the two variables.

Advantages/strengths Disadvantages/ Weaknesses

OBSERVATION

There are two main types of observation - controlled and naturalistic. Controlled observations allow the experimenter to control any variables which may influence behaviour (e.g. noise). Controlled observations are often used within experimental or laboratory designs – for example Milgram’s obedience studies.

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Naturalistic observations do not control any variables as they are purely observational.

In this method people are studied in their natural environment. The researcher does not interfere in any way. They are usually looking for particular types of behaviour e.g. aggression being shown or use of mobile phones etc. Observations may be structured or unstructuredObservations can also be participant or non-participant, covert or overt based.

Complete the following tables and define the terms that follow:Structured Observation

Definition Advantages Disadvantages

Unstructured Observation

Definition Advantages Disadvantages

Covert Observation

Definition Advantages Disadvantages

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Overt Observation

Definition Advantages Disadvantages

Participant Observation

Definition Advantages Disadvantages

Coding system

Inter-rater ReliabilityEvent sampling

Time sampling

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SELF-REPORT METHODS:QUESTIONNAIRE AND RATING SCALES:

Structured questionnaire

Semi-structured questionnaire

Unstructured questionnaire

Rating scales

Closed and open questions

Issues for designClarity of Questions

Bias of Questions

Analysis of results

Pilot Study

Fill in the following tables: -Open questions

Advantages Disadvantages

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Closed questionsAdvantages Disadvantages

Rating ScalesAdvantages Disadvantages

INTERVIEWS

Structured

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Semi-structured

Unstructured

Difficulty of recording answers

Positives about interviews

Negatives about interviews

EVALUATING SELF-REPORT TECHNIQUESMake notes under the following headings TB p 282ValidityExternal validity

Internal validity

Improving validity

RELIABILITYInternal reliability

External reliability

Assessing reliability

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Improving reliability

Case Study

A case study is an in-depth study, using a range of methods on one person or a small group. Because it uses a range of different research methods, this increases reliability, by the process of triangulation. Using a range of different methods is a way of double-checking results. E.g. s Clive Wearing and HM, Little Hans

Strengths:

Weaknesses:

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Which Research Method are the following studies?

Asch 1951

Milgram 1963

Crutchfield 1955

Peterson and Peterson 1959

Clive Wearing

Ainsworth "The Strange Situation" 1978

Loftus 1974

Hofling 1966

Bowlby 1944 "Juvenile thieves"

QUALITATIVE AND QUANTITATIVE DATA IS? TB p 298

CONTENT ANALYSIS TB p 298

What is it?

How do you do it?

Thematic analysis

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Grounded theory

What might the issues be with content analysis?

Sampling

Clearly it is impossible to include all members of the target population within a study so a section of that population, a sample is included instead. Samples should be of a sufficient size to represent the variety of individuals in a target population, but not so large as to make the study uneconomical in terms of time and resources. If a sample is truly representative of the target population, then psychologists should be able to generalise the conclusions/findings of the study to the whole target population.

Random samplingo Every member of the target population has an equal chance of being

selected, Give 3 steps for doing this

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Opportunity samplingUse whoever is immediately available e.g. go out and ask passers-by.Volunteer samplingUse whoever puts themselves forward e.g. advertise in the paper.

Advantages DisadvantagesRandom sampling

Opportunity sampling

Volunteer sampling

Ethical Issues

Why are ethical guidelines important to follow when conducting psychological research?

The main six ethical issues put forward by the BPS are:

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Researchers should also consider following the following three (if applicable):

Which Research Method do I use?

Task: complete the chart using P518 of Nelson Thorne’s text book – see hand-out.

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Reporting Psychological Investigations:

The reporting of psychological investigations is done in a way which ensures that it is both professional and well communicated. Using P278, identify the main elements of each section shown in the diagram below.

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Title

Abstract

Intro

Method

Results

Discussion

Referenc

es

Appendices