Psychology Research Methods

• define aim

  something that identifies the purpose of the investigation and what it is trying to answer
• define hypothesis

  a precise testable statement of what the researchers predict the outcome of the study will be
• define directional hypothesis

  clear and testable statement that predicts a specific outcome
• define non-directional hypothesis

  a clear and testable statement that predicts a difference of relationship but is not specific
• define an independent variable

  a variable that is manipulated or changed by the researcher
• define a dependant variable


  a variable that is measured by the researcher
• define an extraneous variable

  any variable apart from the IV that can affect the dependant variable
• define a confounding variable

  a type of EV but it varies systematically with the IV therefore you cannot tell if the change is due to IV or the CV (we also cannot control it)
• define operationalisation

  clearly defining variables in terms of how they can be measured
• define demand characteristics

  any cue from the researcher or situation that can be interpreted by the participants as revealing the nature or purpose of the investigation. It can lead to the participant changing their behaviour within the research
• define investigator effects

  any (unwanted) effect of the investigator's behaviour on the outcome of the research
• define randomisation

  the use of chance methods to control for the effecs of bias when designing materials order of conditions
• define standardisation

  using the same formalised procedure and instructions for all participants to avoid investigator effects caused by different procedures/instructions
• define experimental design

  the different ways participants can be organised in relation to the experimental conditions
• what is the independant groups design?

  participants are allocated to different groups where each group represents one experimental condition
• give strengths and limitations of independant groups

  + order effects are not a problem

  + participants are less likely to guess the aims, therefore chances of demand characteristics appearing is reduced

  -participant variables may differ (extraneous variable)

  -less economical (one result per subject)

  -twice as many participants needed (difficult to get)
• what is the repeated measures design?

  all participants take part in all conditions of the experiment
• give strengths and limitations of repeated measures

  + participant variables are controlled

  + fewer participants needed

  -introduces order effects

  -boredom, fatigue and skill rehersal can affect performance
• what is the matched pairs design?

  pairs of participants are matched based on key characteristics/ variables that may affect the DV, then are assigned into different groups
• give strengths and limitations of matched pairs

  + no order effects

  + demand characteristics are less of a problem

  + participant variables are greatly reduced

  -participants can never be matched exactly

  -less economical as matching process can be time consuming
• define random allocation

  ab attempt to control for participant variables in an independant group design to ensure each participant has the same chance of being in either condition
• define counterbalancing

  an attempt to control for the effects of order in a repeated measures design
• what is a laboratory experiment?

  An experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effects on the DV. It maintains strict control of EVs
• State strengths and limitations of laboratory experiments

  + high levels of control over extraneous variables give it high internal validity

  + it is replicable, increasing validity and repeatability

  -it has low external validity as it is an articificial setting, so lacks generalisability

  -risk of demand characteristics

  -artificial tasks lead to low mundane realism
• what is a field experiment?

  an experiment which takes place in a natural / real setting, within which the researcher manipulates the IV and records the effects on the DV
• state strengths and limitations of field experiments

  + the more natural environment gives it high mundane realism

  + participants may be unaware, giving high internal validity (reduced demand characteristics and investigator effects)

  -loss of control over extraneous variables

  -possible ethical issues related to a lack of consent and invasion of privacy
• what is a natural experiment?

  an experiment where the change in IV is not brought about by the researcher. The researcher just records the effects on a DV they have decided on
• state strengths and limitations of natural experiments

  + high external validity due to real life issues

  + opportunities for research that would be otherwise impossible

  -low occurnace limits research and generalisability of group to whole population

  -unable to randomly allocate participants
• what is a quasi-experiment?

  a study that is almost an experiment but lacks key aspects such as the IV not being determined or EVs not being controlled but being determined by the natural differences between participants
• state strengths and limitations of quasi-experiments

  + controlled conditions share similar strengths to lab experiments

  + replicable with high internal validity

  -cannot randomly allocate participants, which could lead to confounding variables
• what is a sample?

  a group of people who take part in the investigation that are drawn from the target population and are presumed to be representative of the population
• what is bias?

  when certain groups are over or under represented within the sample selected. It can limit the extent to which generalisations can be made to the target population
• define stratified sampling and how it is carried out

  groups of participants are selected in proportion to their frequency in the target population to obtain a representative sample

  researcher has to identify differen strata making up a population -> calculate proportions -> select participants using random sampling
• give positives and negatives of stratified sampling

  +representative

  +generalisable

  -complete representation is not possible

  -time consuming

  -participants may refuse
• define opportunity sampling and how it is carried out

  a sample of participants produced by selecting people who are most easily available at the time of a study

  select anyone why is willing and available around time of study
• give strengths and limitations of opportunity sampling

  +convenient

  +economic as it is less costly

  -bias due to the researcher having complete control over the participant selection

  -unrepresentative

  -not generalisable
• define systematic sampling and how it is carried out

  selecting every nth person from a line up of the target sample

  produce a sampling frame (organised list of target population) -> nominate a sampling system -> begin from randomly determined start to reduce bias -> work through the list until sample is complete
• give strengths and limitations of systematic sampling

  +objective, therefore no bias

  -time consuming

  -participants may refuse
• define volunteer sampling and how it is carried out

  inviting people to take part in an experiment

  place an advert and allow for volunteers to get back to you
• give strengths and limitations of volunteer sampling

  +minimal input from researcher = not as time consuming

  +participants are enaged

  -volunteer bias

  -not generalisable and representative