Research Methods Psychology

• Strengths and limitations of lab experiments:

  Strengths:

  -High degree control, all variables precisely monitored ^ accuracy

  -Replication Researchers can repeat and check results

  Limitations:

  -Experimenter’s bias: bias can affect results and participants can be influenced by expectations.

  -Lowe ecological validity due to high degree of control= artificial
• S and L of field experiments

  Strength:

  • Naturalistic so higher ecological validity due to natural behaviour
  • Controlled IV

  Limitation

  • Cannot random;y allocate participants to conditions. So there may be confounding variables. make sit harder to conclude the IV caused the DV
• S and L of quasi experiments.

  Strength:

  • Controlled conditions so likely to have high internal validity
  • Replicable

  Limitations:

  • cannot randomly allocate participants to conditions so hard to determine if the IV was hat had an affect on the DV
• S and L Natural experiments

  Strength:

  • Provides research oppourtunities which would have been impossible otherwise due to practical or ethical reasons
  • High external validity as dealing with real life issues.

  Limitation:

  • naturally occurring events, rare so hard to replicate and generalise findings
  • very difficult to randomise into groups so problems with confounding and extraneous variables.
• What is a population in terms of sampling ? 


  A group of people from whom the sample is drawn.
• S and L of opportunity sampling.

  s

  • easy method of recruitment, saves time and money

  L

  • Not representative of the whole population so lacks validity
  • Researcher bias as the researcher chooses who they want to select
• S and L random sampling

  s

  • NO researcher bias as sample random so researcher has no control.

  L

  • Time consuming, researcher needs a sampling frame and contacting people takes a lot of time.
  • Volunteer bias: Participants can refuse to take part so can end up with an unrepresentative sample.
• S and L systematic sampling

  S

  • Avoids researcher ias and farly representative of the population.

  L

  • Not truly unbiased less random number generator is used the. start the systematic sample.
• What is systematic sampling?

  A predetermined system is used whereby every nth number is selected from the sampling frame. the numberical selection is applied consistently.
• S and L of stratified sampling.

  s

  • No researcher bias. selection is done randomly.
  • Produces representative data due to proportional strata. So is generalisable.

  L

  • Time consumming to identify strata and contact people.
  • Identified strata cannot represent differences of all people in a wider population.
• S and L of volunteer sampling

  s

  • Willing participants so easy and not time consuming.
  • Participants more likely to cooperate in study since volunteered to take part.

  L

  • volunteer bias, the study may attract as pacific type of person so genralisability is affected.
  • Ulterior motives like money so participant may not be taking study seriously, which influences results.
• s, l and solu to independent groups design 


  s

  • No order effects presented as participants only do one condition.
  • Demand characteristics are eliminated

  l

  • No control over participant variables. Differnet abilities of participants in conditions can affect DV.
  • You need more participants to gather the same amount of data.

  Solu

  • Random allocation soLoves order effects. Ensures each participat has same likelihood in being in one condition of the iv as the other.
• S, L and solu of repeated measures design

  S

  • eliminates participant variables
  • Fewer participants needed so no as time consuming

  L

  • Order effects

  Solu

  • Counterbalancing when half do one of conditions in one order and half do one of conditions in other order.
• s, l, solu of matched pairs design

  s

  • No order effects
  • demand characteristics are less of a problem.

  L

  • Time consuming and expensive
  • Large pool participants needed which can be hard to get
  • Difficult to know which variables are appropriate to match

  solu:

  n/a
• What is a control group

  Sets a baseline whereby results from the experimental condition can be compared to the results from this one.
• Strengths and limitations of an unstructured observation

  s

  • More richness and depth of detail

  l

  • Produces qualitative data which is more difficult to record and analyse
  • Greater risk of observer bias as will only record catch the eye behaviours
• s and l of structured observation

  s

  • Easier as more systematic
  • Quatitanite data collected, easy to analyse and compare with other data
  • Less risk of observer bias.

  L

  • Not much death of detail
  • Difficult to achieve high inter-observer reliability as filling the predetermined lists is subjective.
• What are behavioural categories

  Target behaviour which is being observed is broken down into precise components which are observable and measurable. EX. agressive behaviour can be punching/swearing.