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LEVEL TWO

RESEARCH METHODS IN PSYCHOLOGY

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Your course lecturer

• Colin Gray

• Room S16 William Guild Building

• E-mail address: c.gray@abdn.ac.uk

• Telephone: (27) 2233

• Don’t hesitate to get in touch with me if you have any queries or encounter any difficulties.

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About the course

• Twelve lectures. • I give my lectures during the first half-session,

but some topics will be useful for the work you will be doing after Christmas as well.

• The lectures are integrated with other courses– the practicals– the workshops on using the computer to analyse data

• A multiple-choice examination.

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To help you …

• I shall try to arrange that the overheads for each lecture are on the Web before the lecture is given.

• I shall give you plenty of examples of multiple-choice questions for practice.

• There’s no need for anyone to fail this course, but I recommend that you PRACTISE AS YOU GO ALONG.

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Purpose of the course

• Psychology is a very wide field of enquiry.

• Different research questions can require quite different methods.

• General principles of good research

• Psychological research produces numerical data.

• How to make sense of psychological data

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To statisticians

• In these lectures, I shall discuss only the most elementary statistical methods.

• If you have already taken a statistics course, you may find some of my later lectures too easy.

• Attendance is not obligatory. Check out each lecture on the Web first.

• Inspect the exam papers in the library to make sure that you are adequately prepared.

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Course textbook

Kinnear, P. R., & Gray, C. D. (2006). SPSS 14 made simple. Hove & New York: Psychology Press.

This book covers most of the topics in this course of lectures.

It will be useful to you next year if you continue with psychology.

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For a broader view of strategies in psychological research

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Lecture 1

STRATEGY IN PSYCHOLOGICAL RESEARCH

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Psychological research is different from research in a natural science,

such as physics or chemistry

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Physics

• ‘If you’ve seen one alpha particle, you’ve seen them all’ (Moore, 1985; p75).

• In physical sciences, the units of study are usually identical.

• So what is true of ONE alpha particle is true of ALL alpha particles.

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Chemistry

• In chemistry, there are books giving the values of ‘Physical Constants’.

• In pure form and under specified conditions, each substance has fixed properties such as a melting point and a boiling point.

• What’s true of YOUR potassium permanganate is true of ALL potassium permanganate.

• To discover the properties of your potassium permanganate (or anyone else’s), just look up the book.

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There are no constants in psychology

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Human variability

• Look at the people entering a lecture theatre.

• They vary in their appearance, their size and their physical proportions.

• They vary in their behaviour.

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Human variability…

• Their psychological characteristics also vary.• So do their attitudes and political affiliations. • Their capabilities also vary.

– How quickly could you slam on the brakes in an emergency?

– How well can you catch and throw a ball?– How quickly and accurately could you identify a guilty

person in a line-up?

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Variable

• The psychologist must deal with VARIABLES.

• A VARIABLE is any characteristic or property with respect to which objects, people or situations can differ.

• Gender is a variable. Height is a variable. The speed with which you can slam on your breaks in an emergency is a variable.

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A key term

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Quantitative and qualitative variables

• Variables such as height, weight and ability level are characteristics that are possessed IN DEGREE. They are QUANTITATIVE variables.

• Characteristics such as gender, nationality and blood group are possessed only IN KIND. They are QUALITATIVE variables.

• Qualitative variables consist of sets of categories and are also known as CATEGORICAL variables.

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Continuous versus discrete variables

• Quantitative variables can, in turn, be divided into those whose values vary CONTINUOUSLY (height, weight) and those whose values vary in steps, that is, DISCRETELY.

• The number of visits to a website, for example, is a discrete quantitative variable.

• So also is the number of heads obtained on ten tosses of a coin.

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Continuous versus discrete …

• A discrete variable can take only a finite number of values between any two points on the scale.

• A continuous variable can take an infinite number of values between any two points on the scale.

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Measurement

• A MEASUREMENT or DATUM is a numerical record of a value (or category) of some variable you are studying.

• A quantitative variable can be measured on an independent scale with units, such as a ruler, a weighing machine or a psychological test. This is ‘measurement’ in the everyday sense of the word.

• I am going to use the word ‘measurement’ in a more general way to include both quantitative and qualitative variables.

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Measurement…

• Qualitative variables can be recorded by using arbitrary code numbers, such as 1 for females and 2 for males. These are also ‘measurements’, in the sense that they are numerical records of observations.

• Here, however, the numbers are merely acting as CATEGORY LABELS. The numbers 9 and 99 (for females and males, respectively) would serve just as well.

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Data

• Measurements are also known as DATA.

• DATA (Latin) is the plural form of DATUM.

• Please write, ‘The data ARE interesting’ or ‘These ARE interesting data’, rather than ‘The data IS interesting’ or ‘This IS interesting data’.

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Establishing causality

• We don’t gather data just for the sake of it.• In psychological research, the researcher

is often trying to show that some variables have CAUSAL EFFECTS upon others.

• Does the watching of violent films make people more violent?

• Do certain drugs improve memory? • Alzheimer’s disease. Violent pornography

on the internet.

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Hypotheses

• Research is motivated by a desire to confirm (or refute) a supposition, or HYPOTHESIS, about nature.

• Often, a hypothesis is a statement to the effect that one variable affects, or causes, another.

• It might be hypothesised, for example, that learning speed initially increases with food deprivation but declines after an optimal level of deprivation has been reached.

• It might be hypothesised that the more violent programmes that children watch on TV or cinema the more violent the children actually become.

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Three strategies in psychological research

1. Experimental

2. Correlational

3. Observational

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Which method is best?

• There is no ‘best’ method. The choice depends upon

1. The research question 2. The state of knowledge in the area3. The circumstances – access to

participants, etc. • Ethical considerations may also

constrain the researcher’s choice of strategy.

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Causality

• Of the three research strategies, experimentation can yield the strongest evidence for causality.

• It is much more difficult to establish causality with the other approaches.

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1. Experimental research

• In experimental research, the experimenter MANIPULATES one variable to demonstrate that it has a CAUSAL EFFECT upon another, which is MEASURED or recorded during the course of the experiment.

• Such manipulation is the hallmark of a true experiment.

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The independent and dependent variables

• The manipulated variable is known as the INDEPENDENT VARIABLE (IV).

• The measured variable is known as the DEPENDENT VARIABLE (DV).

• The experimental results should show whether the IV has a causal effect upon the DV.

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An experiment

• Does food deprivation affect speed of learning?

• Participants are tested on learning speed after different periods of food deprivation.

• Here, the IV (independent variable) is amount of deprivation and the DV (dependent variable) is learning speed.

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A summary of the results

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The true relationship?

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The independent variable

• Note that deprivation (the IV) is NOT a property of the participants in the study – it is a variable MANIPULATED by the experimenter.

• Learning speed (the DV), however, IS a property of the participants and is measured during the course of the experiment.

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Direction of causality

• The concept of ‘cause’ raises many problems. Whole books have been written about it.

• But from the results of this experiment, it is difficult to escape the conclusion that amount of deprivation has a lawful effect upon learning speed.

• Initially, the effect of a little deprivation is to increase speed; but eventually, with increasing levels of deprivation, speed is impaired.

• The research hypothesis is supported by these data.

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2. Correlational research

• In CORRELATIONAL RESEARCH, all variables are measured as they occur in the participants.

• There is NO MANIPULATED VARIABLE.

• All variables are properties or characteristics of the people we are studying.

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Screen violence and actual violence

• Does watching violent material promote actual violence in real life?

• Ethical and practical considerations make it difficult to manipulate the amount of violent material that children watch.

• It is easier to measure children on the amount of screen violence to which they are exposed (or choose to view) and upon their actual violence.

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A study of violence

• We devise a scale measuring actual violence.

• We devise another scale measuring amount of exposure to violent programmes.

• We measure some children on both Exposure to screen violence and Actual violence.

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A scatterplot

• Here is a picture of the results of our study.

• In this SCATTERPLOT, each point represents one of the children.

• Richard got a score of 2 on Exposure and 4 on Actual.

• John got 9 on Exposure and 8 on Actual.

• Jim got scores of 5 on both Exposure and Actual.

Richard

John

Jim

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Correlation

• A statistical ASSOCIATION or CORRELATION is a tendency for events or values to occur together.

• If exposure to screen violence promotes actual violence, we should expect those who watch more violence to be more violent and those who watch less to be less violent. We can expect an ASSOCIATION or CORRELATION between Exposure and Actual violence.

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A strong correlation

• A correlation is evident from the scatterplot.

• When the shape of a scatterplot is a narrow ellipse like this, a strong correlation is indicated.

• This correlation is about .85.

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Scatterplot indicating no association

• When the cloud of points is circular, there is NO ASSOCIATION between the variables.

• We can expect the correlation to be about ZERO.

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Have we really gathered evidence for the hypothesis?

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A famous dictum

CORRELATION

does not imply

CAUSATION

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A causal model

• The hypothesis implies this CAUSAL MODEL.• The results are CONSISTENT with the

hypothesis.• The correlation may indeed arise because

exposure to violence causes actual violence.

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Another causal model

• The child’s violent tendencies towards and appetite for violence lead to his watching violent programmes as often as possible.

• This model is also consistent with the data.

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Yet another causal model

• NEITHER variable causes the other. • Both are determined by the behaviour of the

child’s parents.

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Direction of causality

• Returning to the deprivation experiment, it would be ridiculous to suggest that learning speed determines deprivation.

• In the violence study, however, which was of CORRELATIONAL, rather than EXPERIMENTAL design, the direction of causation is uncertain.

• Indeed, at least three possible MODELS OF CAUSATION are consistent with the results.

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Characteristics of an experiment

• The deprivation experiment embodies two essential features of a true experiment.

1. COMPARISON. 2. CONTROL. • To show that one variable influences another, we must

have a point of reference. Here we can compare ‘baseline’ performance with performance under varying degrees of deprivation.

• We must also be able to ‘control’ the experimental conditions effectively. In this case, the volunteers were prepared to have their food intake controlled by others over the period of the experiment.

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Stroop interference

• You are asked not to READ the words, but to NAME the COLOUR of the print each time.

• It’s difficult to do, because the natural tendency is to read the word.

• The more words there are, the more difficult it gets.

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Demonstration versus experimentation

• The Stroop task is obviously difficult. • But you have not participated in a true

experiment.• There is no element of comparison here: there

was only one condition. • We need to compare the task you have just

attempted with the task of naming the same colours in an array similar to that used for the words.

• We need a comparison or CONTROL condition.

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The rule of one variable in experimental design

• In a true experiment, there must be at least two conditions.

• If there are just two conditions, one of them is usually a comparison or CONTROL condition.

• The comparison or CONTROL condition must differ from the active or EXPERIMENTAL condition only in the absence of the active agent. In all other respects, the two conditions must be identical.

• In the Stroop experiment, participants must also be asked to name the colours of non-word patterns.

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A control (comparison) condition

• In fact, it is much more difficult to name colours than to read words.

• Even so, Stroop (1935) showed that it takes much longer to name the print colour of the conflicting colour words.

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Extraneous or confounding variables

• It is often very difficult to devise an appropriate control condition in accordance with the rule of one variable.

• If the control condition differs from the experimental condition in more than one way, this characteristic may be entangled or CONFOUNDED with the independent variable.

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3. Observational research

• In the third kind of research, the researcher neither manipulates variables nor measures them as they occur in participants.

• In OBSERVATIONAL RESEARCH, the researcher simply records what the participant says and does.

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Natural history

• As examples, we have the classic observational studies of animal behaviour.

• In his book King Solomon’s Ring, the naturalist Konrad Lorenz describes his highly influential observations on such behaviour as imprinting in ducklings.

• The French entomologist Jean-Henri Fabre observed and described the behaviour of the hunting wasp.

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Case histories

• In psychology or psychiatry, the counterpart of the natural history study is the CASE HISTORY, the reports of Sigmund Freud and Kraftt-Ebbing being classic examples.

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The participant observer

• What causes football violence?• Researchers have infiltrated football gangs and

attempted to discover the social dynamics of violence. • Big business makes extensive use of techniques of

persuasion, and not just in advertising. The Tupperware organisation trained a large staff to organise parties at which those present were persuaded to host their own parties later. Specially trained Tupperware personnel would bring great pressure to bear upon guests to make a commitment to host their own parties at some specified future date.

• The Tupperware training methods have been described by Taylor (1975), who arranged for members of his research team to infiltrate a Tupperware group and observe their methods.

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Phenomenology: Enquire within

• PHENOMENOLOGY (Brentano) is a philosophical doctrine which held that psychology should be based upon IMMEDIATE EXPERIENCE.

• There have always been psychologists who argue that psychology should be less about numerical data and more about people’s descriptions of how things seem to them personally.

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Introspection

• The principal research tool of the phenomenologist is INTROSPECTION, which is description of one’s own thoughts and experiences.

• This method is still used in modern psychology, as when chess players and other problem-solvers are asked to ‘think out loud’ as they play.

• It is hoped that this INTERIOR MONOLOGUE will reveal the nature of the thought processes involved.

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Advantages of observational research

• Experiments can seem highly artificial. • Observational studies in natural settings

seem to have more ECOLOGICAL VALIDITY.

• Modern advances in technology have provided powerful aids to observational work. Infra-red photography, for example, has contributed enormously to our knowledge of nocturnal animal behaviour.

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Technology…

• We now know much more about the true habits of hyenas, once thought to be cowardly scavengers, as they roam the noctural African landscape.

• Similarly, CCTV footage has revealed the behaviour of packs of human predators as they roam a nocturnal urban landscape as nightmarish as that envisaged by Anthony Burgess in his book Clockwork Orange. His dystopic vision has proved to be prophetic. Burgess’s creation, Little Alex, who horrified a generation, is alive and well today.

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The qualitative approach

• Recent years have seen a resurgence of phenomenology in the form of QUALITATIVE RESEARCH (Rennie, Watson & Monteiro, 2002).

• Buchbinder & Eiskovits (2002), having studied the detailed accounts of 20 women’s experiences of domestic violence, concluded that it is primarily shame that prevents victims of domestic violence from reporting the crime to the police.

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Problems with observational research

• The observer is not like a video-recorder any more than memory is like a filing cabinet.

• Like memory, observation is a highly selective process and driven by the assumptions and expectations of the observer.

• There are numerous records of eminent scientists seeing what they expected to see, rather than what was actually there.

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Belief-motivated perception

• Seeing is believing; but believing can also lead to seeing and what is seen may not actually be there.

• The microscopist Von Hartsoeker, a preformationist, believed that he could see, in a human spermatozoon, a tiny baby in such clarity of detail that he was able to draw it.

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Introspection – or retrospection?

• Arguably, INTROSPECTION is actually RETROSPECTION and hindsight can be misleading.

• Critics of the ‘thinking aloud’ approach to chess have argued that such verbalisation not only fails to reveal the true processes involved, but may actually alter the thinking of the solver.

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Instrument reactivity

• The process of any kind of observation, whether in a naturalistic or a laboratory setting, can affect the nature of what is measured.

• The participant observer who has infiltrated a football gang may, in order to conceal his true role and hidden agenda, feel forced to influence the social dynamics of the group.

• The manner in which he does this may reflect his own ideas about the dynamics of group violence.

• The Buchbinder and Eiskovits study raises several questions. Is the explanation of the women’s reticence really shame, as they say, or something else?

• Did those authors read their own preconceptions into the women’s scripts?

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In summary

• Much psychological research attempts to show that some variables exert a causal influence over others.

• I reviewed three main strategies: 1. Experimental2. Correlational3. Observational• Each approach has its advantages and

disadvantages.

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Key terms

• variable• quantitative versus qualitative variables.• continuous versus discrete variables.• measurement, datum, data. • hypothesis• experimental, correlation and observational

research. • Independent variable, dependent variable.• scatterplot.

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Key terms…

• correlation• correlation versus causation• causal model• control • Stroop interference • demonstrations versus experiments• rule of one variable• extraneous variables, confounding

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Key terms …

• case history

• participant observation

• phenomenology

• introspection

• interior monologue

• ecological validity

• qualitative research

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Key terms …

• belief-motivated perception

• Instrument reactivity

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Multiple-choice example

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