Research Methods

• What does it mean by experimental method?

  > concerns the manipulation of the independent variable (IV) to have an effect on the dependent variable (DV), which is measured and stated in results

  > can be: field, laboratory, natural or quasi
• What is an aim?

  > a general statement made by the researcher which tells us what they plan on investigating -> the purpose of their study

  > they are developed from theories and develop from reading about similar research
• What is a hypothesis?


  > a precise statement which clearly states the relationship between the variables being investigated

  > can be directional or non-directional

  > a directional hypothesis states the direction of the relationship that will be shown between the variables (one-tailed)

  > a non-directional does not (two-tailed)
• When is a directional hypothesis most likely to be used?

  > when there's already been a range of research carried out which relates to the aim of the researchers investigation

  > this data would suggest a particular outcome
• When is a non-directional hypothesis most likely to be used?

  > when there's no previous research relating to the studies aim

  > or the research is contradictory
• What is the independent variable (IV)?


  > refers to the aspects of the experiment which has been manipulated by the researcher or simply changes naturally to have an effect on the DV which is measured

  > what is changed
• What is a dependent variable (DV)? 


  > the aspect of the study which is measured by the researcher and has been caused by a change to the IV

  > all other variables that could affect the DV should be carefully controlled so that the researcher is able to confidently conclude that the effect on the DV was caused by only the IV

  > what is measured
• How do you properly test the effect of the IV?

  > need different conditions: experimental condition and control condition

  > can have various experimental conditions which will allow you to compare the effects of different levels of the IV
• What is operationalisation?


  > the act of a researcher clearly defining the variables in terms of how they are being measures

  > means: variables should be defined and measurable

  > the hypotheses states should also show this operationalisation

  > e.g. "participants that get at least four hours of sleep will show better performance on the memory test, shown by them achieving higher scores than participants that got less than four hours of sleep"
• What are extraneous variables?

  > any other variable which isn't the IV that affects the DV and doesn't vary systematically with the IV

  > examples = age of participants, the lighting in the lab

  > these variables don't confound the results of a study but make just make them harder to detect
• What are confounding variables?

  > describes as a variables other than the IV which has an affect on the DV

  > they do change systematically with the IV

  > it becomes difficult for the researcher to be sure of the origin of the impact of the DV as the confounding variable (not IV) could have been the cause

  > example: time of day memory test is taken -> if done later on may be more tired so do worse

  > so potential confounding variables must be identified and controlled -> all ppts take test at same time of day
• What are demand characteristics?

  > any cue the researcher or the research situation may give which makes the ppt feel like they can guess the aim of the investigation

  > can cause the ppt to act different within the research situation from how they would usually act -> may change their behaviour to fit the situation rather than acting naturally

  > this unnatural behaviour affects the validity of the results
• What are investigator effects?

  > any unwanted influence from the researcher's behaviour, either conscious or unconscious, on the DV measured (the research's results)

  > this includes a variety of factors: design of study, selection of ppts and interaction with each ppt during the research investigation
• What steps can be taken to minimise the effects of extraneous or confounding variables?

  > randomisation

  > standardisation
• What is randominsation?

  > the use of chance to reduce the effects of bias from the investigator effects

  > can be done for the design of materials, deciding the order of conditions, the selection of ppts, etc
• What is standardisation?

  > using the exact same formalised procedures and instructions for every single ppt involved in the research process

  > this allows there to eliminate non-standardised instructions as being possible extraneous variables
• What are the different experimental methods?

  > laboratory

  > field

  > quasi

  > natural
• What is a laboratory experiment?

  An experiment that takes place in a special environment whereby different variables can be carefully controlled
• What are some strengths of laboratory experiments?

  > high degree of control = experimenters control all variables. IV been precisely replicated, leading to greater accuracy

  > replication = researchers can repeat experiments and check results
• What are some limitations of laboratory experiments?

  > experimenter's bias = this bias can affect results and ppts may be influenced by these expectations

  > low ecological validity = high degree of control makes the situation artificial, unlike real life
• What is a field experiment?

  An experiment conducted in a more natural environment, not in a lab but with the variables still being well controlled
• What are some strength of field experiments?

  > naturalistic = more natural behaviours hence high ecological validity

  > controlled IV
• What are some limitations of field experiments?

  > ethical considerations = invasion of privacy and likely to have been no informed consent

  > loss of control = over extraneous variables hence precise replications not possible
• What is a quasi experiment?

  An experiment whereby the IV has not been determined by the researcher, instead it naturally exists, e.g. gender difference studies

  > IV is a difference between people -> gender, age, etc
• What is a strength of a quasi experiment?

  > controlled conditions = replicable, likely to have high internal validity
• What is a limitation of a quasi experiment?

  > can't randomly allocate ppts to conditions = there may be confounding variables

  > This makes it harder to conclude that the IV caused the DV
• What is a natural experiment?

  An experiment in which the IV is not brought about by the researcher -> would have happened even if the researcher had not been there (naturally occuring). e.g. if studying reactions to earthquakes
• What are some strengths of natural experiments?

  > Provides opportunities = for research that would have otherwise been impossible due to practical or ethical reasons

  > high external validity = as dealing with real life issues
• What are some limitations of natural experiments?

  > naturally occurring events = may be rare so these experiments are not likely to be replicable -> hard to generalise findings

  > very difficult to randomise ppts into groups = confounding and extraneous variables become a problem
• What are the different sampling methods?

  > opportunity sampling

  > random sampling

  > systematic sampling

  > stratified sampling

  > volunteer sampling
• What is opportunity sampling?

  Participants happen to be available at the time which the study is being carried out so are recruited conveniently
• What is a strength of opportunity sampling?

  > easy method of recruitment = time saving & less costly
• What are some limitations of opportunity sampling?

  > not representative of whole population = lacks generalisability

  > researcher bias presented = they control who they want to select
• What is random sampling?

  > all members of the population gave the same equal chance of being the one that is selected

  > each member assigned with a number

  > then a random number table/random number generator is used to randomly choose a partner
• What is a strength of random sampling?

  > no researcher bias = researcher has no influence over who is picked
• What are some limitations of random sampling?

  > time consuming = need to have list of members of population (sampling frame) then contacting them takes time

  > volunteer bias = ppts can refuse to take part so can end up with an unrepresentative sample
• What is systematic sampling?

  > A predetermined system is used whereby every nth member is selected from sampling frame

  > this numerical selection is applied consistently
• What are some strengths of systematic sampling?

  > avoid researcher bias = they have no control over who is chosen

  > usually fairly representative of population
• What is a limitation of systematic sampling?

  > not truly unbiased unless use a random number generator and then start systematic sample
• What is stratified sampling?

  > the composition of the sample reflects the varying proportions of people in particular subgroups (strata) within the wider population

  > firstly you identify strat

  > the you calculate the required proportion needed for each stratum based on the target population

  > Then select sample at random from each stratum using a random selection method