research methods Flashcards
Timeline of psychological experiments
- Come up with a theory (based on research)
- Narrow focus and produce an aim for your investigation
- Formulate a hypothesis
- Conduct your experiment
An aim
- an aim is developed from a theory
- a theory has been extensively researched before going ahead with an investigation to test the theory
- An aim in psych is a general statement that describes the purpose of an investigation
hypotheses
- written after the aims
- is made at the start of a study that clearly states the relationship between two variables
- A hypothesis should always include the IV and the DV
- can either be directional or non-directional
directional hypotheses
(“one tailed”)
- used when you can know or predict from previous research which way this piece of research should go
- the researcher makes clear the sort of difference that is anticipated between two conditions or two groups of people
- generally, a directional hypothesis will include words such as higher, lower, less, more, faster, slower
- eg. people who drink red bull will be more talkative than people who don’t
non-directional
(“two tailed”)
- used when you don’t know which direction it is going in
- doesn’t state the direction of the research BUT states there will be a difference
- we usually use this if we don’t have any previous research in the area to base our prediction off
- eg. there will be a difference in chattiness dependent on whether people have red bull or water
independent variable (IV)
- factor that is directly manipulated by the experimenter
- there are at least two levels of IV in an experiment
Dependent Variable (DV)
- measured by the experimenter to assess the effects of the IV
- all other variables should be controlled/kept constant
Levels of the Independent Variable
- in order to test the effect of the IV we need different conditions
- For example, if we are looking at energy drinks and happiness, we would need a condition to compare the energy drinks one to
- the one without an energy drink would be called a control condition and the one with is called the experimental condition
- there could be multiple experimental conditions
control condition
lacks any treatment or manipulation of the independent variable.
experimental condition
- receive treatment or manipulation of the independent variable
- could be multiple experimental conditions
Operationalisation of Variables
- variables (IV and DV) must be operationalised. This means defined in a way they can be easily tested and measured.
- eg. if we wanted to see the effect of energy drinks on memory, we would need to operationalise it by saying how we are measuring memory (eg. a test) and how we are going to keep the IV consistent
Writing Hypotheses
- it must be clear and testable
- make sure that…
1. The IV and DV are clear and measurable
2. You have stated the relationship between the IV and DV
3. You have selected an appropriate hypothesis (directional or non-directional based on the information you have been given in the stem of the question)
how to identify an experiment hypothesis
- experiment
- ‘causes’
- effectiveness
how to identify a correlation hypothesis
- relationship
- link
- association
sentence starter for experiment (directional) hypotheses
there will be an [increase/decrease/more/less/higher/lower] in..
sentence starter for experiment (non-directional) hypotheses
there will be a difference in…
sentence starter for correlation (directional) hypotheses
there will be a [positive/negative] relationship between…
sentence starter for correlation (non-directional) hypotheses
there will be a relationship/association between…
extraneous variables
- other (non-IV) variables that may interfere with the experiment by affecting with the DV and so need to be controlled
- can be divided into participant and situational variables
participant variables
any individual differences between participants that may affect the DV
situational variables
any features of the experimental situation that may affect the DV
confounding variables
any variable, other than the IV, that may have affected the DV. They vary systematically with the IV (whereas extraneous do not).
features of confounding variables
- They just crop up and we cannot control for them because we don’t know they are going to happen
- They are usually found once the experiment has been conducted
- Almost like an unintentional second IV - something else you are changing
demand characteristics
this is a type of extraneous variable… Any cue from the researcher or from the research situation that may be interpreted as revealing the purpose of the investigation. This can lead to participants changing their behaviour. Examples include the please-u and screw-u effect.
please-u effect
participants may, for example, try to please the researcher by doing what they have guessed is expected of them
screw-u effect
They may deliberately try to skew the results, attempting to the opposite of what they think is expected
investigator effects
any effect of the investigators behaviour (conscious or unconscious) on the research outcome (the DV). This may include the design of the study, the selection and interaction with participants, the materials and instructions. Leading questions eg. “are you happy with the study?” may also have been an investigator effect.
variable that is differences between participants
participant variables (a type of extraneous)
variable that is features of the experimental situation
situational variables (a type of extraneous)
variables that vary systematically
confounding
variables that have random effects
extraneous
when ppt change their behaviour due to guessing the aim of the experiment
demand characteristic
investigators behaviour variable
investigator effects
ways to minimise extraneous or confounding variables
- randomisation
- standardisation
- single-blind trials
- double-blind trials
randomisation
involves the use of chance in order to control for the effects of bias when designating materials and deciding the order of conditions
standardisation
using exactly the same formalized procedures and instructions for all participants.
single-blind
participants are not told the aim of the research (or other important details like the presence of another group)
double-blind
neither the participant or the researcher who conducts the study is aware of the aims of the investigation (third-party researcher is brought in)
repeated measures
The same participants take part in the each condition of the IV. This means that each condition of the experiment includes the same group of participants.
strengths of repeated measures
- participant variables are controlled (no differences between two groups)
- more economical (less participants)
weaknesses of repeated measures (and ways to deal with these)
- order effects (fatigue or boredom) - practice effect
- demand characteristics
= could use two different (but similar) tests or randomise the items
= counterbalancing participants (half A then B, half B then A)
independent measures
Different participants are allocated to two (or more) experimental groups representing different levels of the IV. There may also be a control group.
strengths of independent measures
- less likely to have demand characteristics
- shouldn’t have the order effects
weaknesses of independent measures (and ways to deal with these)
- less economical because you need more people
- extraneous variables/participant variables
= random allocation
Matched pairs
This is where participants are matched for similar key variables eg. same IQ or same age etc. This means that there are two groups of participants. One group do condition A and one group do condition B.
strengths of matched pairs
- less likely to have demand characteristics
- shouldn’t have the order effects
- participant variables are more controlled
weaknesses of matched pairs (and ways to deal with these)
- less economical because you have more people
- time consuming and expensive to match the people
- do still have participant variables (although should be very low)
= could conduct a pilot study before to identify important variables to match pairs on (reduce participant variables even further)
random allocation
participants are allocated to each IV randomly eg. names from a hat
types of experiment and how to identify them
- lab (manipulated in a non-natural/controlled setting)
- field (manipulated in a natural setting)
- natural (change but outside of investigators control)
- quasi (un-manipulatable characteristics)
lab experiments
conducted in highly controlled environments. This is not always a laboratory - it could, for example, be a classroom where conditions can be well controlled.
- participants tend to GO to the “lab”
strengths of lab experiments
- high control over extraneous variables (so that any effect on the DV is likely to be the result of manipulation of the IV)
- can be more certain about demonstrating cause and effect
- replication is more possible than in other types of experiment because of the high level of control (ensures that new extraneous variables are not introduced)
limitations of lab experiments
- may lack generalisability as the lab environments may be quite artificial (the participants may act in unusual ways) - low external validity
- participants are usually aware they’re being tested which may also give rise to ‘unnatural’ behaviour (demand characteristics)
- the tasks participants are asked to carry out may not represent real-life experience (low mundane realism)
example of lab experiments
eg. Johnson and Scott (1979) tested the impact of anxiety on eye witness testimony - a weapon in a criminal’s hand distracts attention (because of the anxiety it creates) from other features and therefore reduces the accuracy of identification.
- participants were asked to sit in a waiting room where they heard an argument in an adjoining room
- one group then saw a man run through the room carrying a pen covered in grease (low anxiety condition) or a knife covered in blood (high anxiety condition)
- they were later asked to identify the man from a set of photographs
Mean accuracy was 49% in identifying the man in the low anxiety condition compared with 33% accuracy in the knife condition.
external validity
the extent that the results can be generalised to the rest of the population
mundane realism
level of everyday reality - effects participant behaviour
field experiments
the IV is manipulated in a natural, more everyday setting (in the field)
strengths of field experiments
- higher mundane realism because the environment is more natural
- may produce behaviour that is more valid and authentic
- participants may be unaware they are being studied (high external validity)
limitations of field experiments
- loss of control of extraneous variables (cause and effect between the IV and DV is difficult to establish and replication is often not possible)
- important ethical issues (people don’t know they are being studied so cannot consent - invasion of privacy)
example of a field experiment
eg. Rutter et al. (2011) conducted a longitudinal study on 165 Romanian orphans adopted by British parents.
- children were split into 4 groups:
1. Group 1 - 58 children under the age of 6 months
2. Group 2 - 59 children between 6 months and 24 months (2yrs)
3. Group 3 - 48 children over 48 months (4yrs)
4. Group 4 - 52 British adoptees who were the control group
- each group was assessed at the ages of 4, 6, 11, and 15
At the start of the observations, over half of the Romanian children were suffering from severe malnutrition and a low IQ, showing delayed intellectual development, compared to the control group.
natural experiments
when the researcher takes advantage of a pre-existing independent variable (this is ‘natural’ because the variable would have changed anyway) - naturally manipulated IV
strengths of natural experiments
- provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons
- high external validity because they study real-life issues and problems as they happen
limitations of natural experiments
- a naturally occurring event may only happen very rarely, reducing the opportunities for research and limit the scope for generalising findings
- participants may not be randomly allocated to experimental conditions (so the researcher might be less sure whether the IV affected the DV)
example of a natural experiment
eg. Rutter et al. (2011) conducted a longitudinal study on 165 Romanian orphans adopted by British parents.
- children were split into 4 groups:
1. 58 children under the age of 6 months
2. 59 children between 6 months and 24 months (2yrs)
3. 48 children over 48 months (4yrs)
4. 52 British adoptees who were the control group
- each group was assessed at the ages of 4, 6, 11, and 15
At the start of the observations, over half of the Romanian children were suffering from severe malnutrition and a low IQ, showing delayed intellectual development, compared to the control group.
Quasi-experiments
have an IV that is based on existing difference between people (eg. age or gender). No one has manipulated this variable, it simply exists. - IV could not be manipulated at all
strengths of Quasi-experiments
often carried out under controlled conditions and therefore share the strengths of a lab experiment:
- high control over extraneous variables
- can be more certain about demonstrating cause and effect
- replication is more possible than in other types of experiment (ensures that new extraneous variables are not introduced)
limitations of Quasi-experiments
- cannot randomly allocate participants to conditions and therefore there may be confounding variables
example of a Quasi-experiment
eg. Sheridan and King (1972) tested obedience between genders.
- The participants were asked to give genuine electric shocks of increasing strength to a puppy
54% of the male participants gave the maximum (non-fatal) shock in contrast to 100% of the female participants.
what is a ‘true experiment’?
the IV is under the direct control of the researcher, lab and field are true experiments
case studies
- to make a detailed and in-depth analysis of an individual, small group, institution or event
- often unique and involve studying a situation that is unusual (eg. a rare disorder)
- can also focus on more typical events (eg. a group of elderly people recollecting events of their upbringing)
- varied but always gather rich data in qualitative form
what might a case study involve?
- A case history of the individual/group - interviews, questionnaires, observations to gather qualitative data
- Gathering other forms of data - psychometric or psychological tests to collect quantitative data that can be used alongside the qualitative
- Deciding the length of time the study will run and if any additional participants are needed - most case studies are longitudinal (take place over a long period of time) and may involve gathering additional data from family and friends
strengths of case studies
- rich, detailed insights that can shed light on very unusual forms of behaviour
- contribute to our understanding of normal functioning (especially in brain damage cases)
- may generate interest and highlight a need for further, perhaps more scientific methods of investigation
- allows investigations that would otherwise be unpractical or unethical
limitations of case studies
- cannot generalise results to the wider population
- researchers own subjective feelings may influence the case study
- accounts from individuals/friends/family may hold inaccuracies
- very difficult to replicate (so cannot check for reliability)
- time consuming, both to conduct and analyse
temporal validity
- may not be applicable to the current time period
- societal change OR research methods used were less rigorous and controlled
observational techniques
there are 6:
- naturalistic
- controlled
- covert
- overt
- participant
- non-participant