SPECIFICATION BREAKDOWN
· Experimental methods. Types of experiment, laboratory and field; natural and quasi-experiments
· Observational techniques. Types of observation: naturalistic and controlled; covert and overt observation; participant and non-participant observation
· Self-report techniques. Questionnaires; interviews, structured and unstructured
· Correlations. Analysis of the relationship between co-variables. The difference between correlations and experiments
· Content analysis
· Case studies
SCIENTIFIC PROCESSES
· Aims: stating aims, the difference between aims and hypotheses
· Hypotheses: directional and non-directional
· Sampling: the difference between population and sample; sampling techniques including: random, systematic, stratified, opportunity and volunteer; implications of sampling techniques, including bias and generalisation
· Pilot studies and the aims of piloting
· Experimental design (independent groups, repeated measures, matched pairs)
· Observational design: behavioural categories; event sampling; time sampling
· Questionnaire construction, including use of open and closed questions; design of interviews
· Variables: manipulation and control of variables, including independent, dependent, extraneous, confounding; operationalisation of variables
· Control: random allocation and counterbalancing, randomisation and standardisation
· Demand characteristics and investigator effects
· Ethics, including the role of the British Psychological Society’s code of ethics; ethical issues in the design and conduct of psychological studies; dealing with ethical issues in research
· The role of peer review in the scientific process
· The implications of psychological research for the economy
· Reliability across all methods of investigation. Ways of assessing reliability: test-retest and inter-observer; improving reliability.
· Types of validity across all methods of investigation: face validity, concurrent validity, ecological validity and temporal validity. Assessment of validity. Improving validity.
· Features of science: objectivity and the empirical method; replicability and falsifiability; theory construction and hypothesis testing; paradigms and paradigm shifts.
· Reporting psychological investigations. Sections of a scientific report: abstract, introduction, method, results, discussion and referencing.
DATA HANDLING AND ANALYSIS
· Quantitative and qualitative data; the distinction between quantitative and qualitative data collection techniques
· Primary and secondary data, including meta-analysis
· Descriptive statistics: measures of central tendency - mean, median, mode; calculation of mean, median and mode; measures of dispersion; range and standard deviation; calculation of percentages; positive, negative and zero correlations
· Presentation and display of quantitative data: graphs, scatter grams, tables, bar charts, histograms
· Distributions: normal and skewed distributions; characteristics of normal and skewed distributions
· Analysis and interpretation of correlation, including correlation coefficients
· Levels of measurement: nominal, ordinal and interval.
· Content analysis and coding. Thematic analysis.
INFERENTIAL TESTING
· Introduction to statistical testing; the sign test
· Probability and significance: use of statistical tables and critical values in interpretation of significance; Type I and Type II errors.
· Factors affecting the choice of statistical test, including level of measurement and experimental design. When to use the following tests: Spearman’s rho, Pearson’s r, Wilcoxon, Mann-Whitney, related t-test, unrelated t-test and Chi-Squared test.
By the end of the Research Methods course, these are the key terms you should be able to define.
As we go through each lesson, complete the definitions.
Key term / Definitionaim
behavioural categories
closed-ended questions
confounding variable
control group
controlled observation
correlation coefficient
counterbalancing
demand characteristics
dependent variable
directional hypothesis
double blind
ethical issues
event sampling
experimenter bias
extraneous variables
field experiment
hypotheses
independent groups
independent variable
inter-observer reliability
investigator effects
laboratory experiment
matched pairs
measures of central tendency
measures of dispersion
volunteer sampling
meta-analysis
natural experiment
naturalistic observation
non-directional hypothesis
null hypothesis
observer bias
open- ended questions
operationalisation
opportunity sampling
order effects
peer review
pilot study
qualitative data
quantitative data
random sampling
range
repeated measures
self-selecting sampling
single blind
social desirability bias
standard deviation
standardised instructions
stratified sampling
systematic sampling
target population
time sampling
Experimental methods
There are a number of different research methods in Psychology and psychologists choose the most appropriate method for their research. No single method is better than another – they each have their strengths and weaknesses.
Quantitative data:
Qualitative data:
The experimental method refers to a research method using the assignment of participants to different conditions and the manipulation of variables in order to determine cause and effect. A variable is any object, characteristic or event that changes or varies in some way. Experiments are the most widely used method in psychology.
Manipulation of causes a change in the
Independent variable Dependent variable
E.g. amount of revision level of exam success
The experimenter manipulates an independent variable (IV) to see its effect on the dependent variable (DV).
The IV is the variable that’s manipulated or altered by the experimenter to see its effect on the DV.
The DV is the measured result of the experiment (as a result of the change in IV).
E.g.
Extraneous variables are any other variables that may have an effect on the DV. Controls are employed to prevent extraneous variables affecting the result – any extraneous variables that are not controlled can become confounding variables (because they confound or confuse the result).
Extraneous variables:
Confounding variables:
Read the brief descriptions of 3 memory studies and identify the IV and DV in each one.
1. Baddeley (1966) investigated the effects of acoustic similarity on serial recall performance by presenting Ps with a list of 5 short words that sound alike (e.g. man, mat, map, can, cap) and 5 short words that do not sound alike (e.g. pen, day, few, cow, pit).
2. Tyler et al. (1979) gave Ps 2 sets of anagrams to solve: one set was easy (e.g. doctor) and the others were more difficult (e.g. cdrtoo). They were then unexpectedly asked to recall as many of the words as possible. The aim was to test the prediction that it is the amount of processing effort rather than the depth of processing that affects memory retention.
3. Psychologists have been interested in the effects of the learning environment on memory recall. Smith (1979) gave Ps a list of 80 words to learn while sitting in a distinctive basement room. The following day he tested some of the Ps in the same basement room, others in a fifth-floor room with very different décor, and a third group in another upstairs room where Ps were instructed to imagine themselves back in the basement room.
The IV is something that is manipulated/changes to bring about a change in behaviour that is measured (DV).
Control
Control is achieved when, other than the ______variable, all other variables (known as ______variables) are held constant so the change in the ______variable can only be due to manipulation of the IV. If all other variables are controlled then any ______in outcomes between the different groups of the IV must be due to the change in the ______variable.
Randomisation
Participants may be ______allocated to different conditions of the IV, for example by flipping a ______or using odds and ______with a random number table. This is to ensure that any extraneous variables linked to the ______are as likely to affect one group as the other and will have little or no effect on the DV. Other things may be randomised too, such as the ______in which participants take part in the experiment.
Standardisation
This means that all the participants in an investigation have exactly the same ______. This ensures that individual experience does not cause the participants to engage with the study differently. Procedures need to be ______(i.e. the same every time). The ______given to the participants need to be exactly the ______so that if there is an error in interpretation it affects all participants in all ______equally.
independent / independent / dependent / order / participantrandomly / extraneous / coin / difference / evens
standardised / experience / same / conditions / instructions
Complete the following table.
Description
Advantages
Disadvantages
Summary of experimental research methods
Type of experiment / Variable details / EnvironmentLaboratory
Field
Natural
Quasi
Match each of the studies below to an experimental method:
a) Laboratory experiment
b) Field experiment
c) Natural experiment
d) Quasi experiment
1. ______
A psychologist wanted to study the effect of helping behaviour on a New York subway. An actor (working with the psychologist) pretended to collapse on a train. The psychologists then measured how many people helped in different situations: a) when he was smartly dressed, b) when he was shabbily dressed and smelt of alcohol and c) when he had blood coming out of his mouth. (Piliavin et al. 1969)
2. ______
A group of researchers wanted to study the effect of television on anti-social behaviour. An island in the South Pacific introduced TV for the first time in 1995. The researchers studied behaviour on the island before the introduction of television (assessing pro and anti-social behaviour) and compared behaviour on the same measures after TV was introduced. (Charlton et al. 2000)
3. ______
A group of students wanted to study the effects of a distraction task on short-term memory. They randomly selected participants from the register at school and told them to go to the Psychology classroom at lunchtime. The participants were divided into two groups: Group A and Group B. Both groups were given a list of 15 words and asked to memorise them for 1 minute. Afterwards, Group A were given a short maths task (distraction task) and then asked to recall the words. Group B were not given a distraction task, and were then asked to recall the words.
4. ______
A researcher wanted to investigate the impact of age on accurate memory recall; they had three conditions; child, teenager and young adult. They showed all participants a video of a crime and gave them a memory test afterwards to see how accurate their recall was after the event.
Extension task
Identify the IV, DV, possible EVs, the aim and a hypothesis for each experiment.
Aim: a reasonably precise statement of why a study is taking place, including what’s being studied and what the study is trying to achieve.
Hypotheses: this is more precise than an aim and predicts what is expected to happen. It is a testable statement of the relationship between two variables.
There are two types of hypotheses:
1. Experimental / Alternative hypothesis
2. Null hypotheses
One of these hypotheses will be supported by the findings and one will be rejected.
There are also two types of experimental / alternative hypothesis.
1. Directional (also called one-tailed)
2. Non-directional (also called two-tailed)
A non-directional hypothesis is used in two situations:
a)
b)
When would a directional hypothesis be used?
Exam question
A researcher carried out an experiment to see how many items could be held in short-term memory. The participants were 15 adults and 15 children. Participants were asked to repeat random lists of numbers, in the correct order, as soon as they were read out by the researcher. For example, when the researcher said “3, 4, 2, 8”, the participant immediately repeated “3, 4, 2, 8”. When the researcher then said “7, 5, 9, 6, 4”, the participant immediately repeated “7, 5, 9, 6, 4”. One number was added to the list each time until participants were unable to recall the list correctly. Each participant’s maximum digit span was recorded.
Write an appropriate non-directional hypothesis for this experiment. (2 marks)
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Read the hypotheses below and identify the independent variable (IV) and the dependent variable (DV). State whether each hypothesis is directional or non-directional.
Hypothesis / IV / DV / Directional/ Non-directionalThere will be a difference in number of words recalled between people who are instructed to organise words and people who are instructed to memorise words.
Children who spend more than 20 hours a week in day-care will be rated as more sociable than children who do not go to day-care.
People who smoke are more likely to develop a wider range of cancers than people who do not smoke.
There will be a difference in the number of words recalled by participants who learned them in a noisy room and participants who learned them in a quiet room.
People who drive at a faster speed will drive less safely than people who drive at a slower speed.
There will not be a difference in the reaction times between people who have had 2 cups of coffee and people who have had no coffee.
People who have drunk three beers will recall fewer words than people who have not drunk any alcohol.
Students who study Psychology A-level will be more likely to go to university than students who do not study Psychology A-level.
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Operationalisation of variables
The term ‘operationalisation’ means being able to define variables simply and easily in order to manipulate them (IV) and measure them (DV).
Sometimes this is very easily done – for example if we were investigating the effect of alcohol consumption on reaction times we could operationalise the variables as:
IV:
DV:
However, on other occasions this is more difficult. When ‘operationalising’ anger or stress levels the researcher has to make a judgement as to whether they are actually measuring the variables they hope to be measuring.
Practice with the examples below.
Psychological variable(the thing we can’t see) / Operational definition
(the thing we can measure)
Health
Attractiveness
Short-term memory
Intelligence
Aggression
Stress levels
Reading ability
Social development
A major problem with the operationalisation of complex variables is that they often only measure one aspect of the variable.
However, both the IV and DV need to be operationalised accurately and objectively to maintain reliability and validity of a study. Without this, results cannot be checked nor replicated.
For each of the two studies below answer the following questions:
1. Identify the IV and DV.
2. How could the IV and DV be operationalised?