(1) Experimental Method and Types of Data

• research methods in psychology are systematic procedures used to :

  • observe
  • describe
  • predict
  • explain

  behaviour and mental processes
• research methods include :

  • experiments
  • surveys
  • case studies
  • Naturalistic observations
• research methods ensure the data that is collected is objective and reliable to understand and explain psychological phenomena
• research methods are the procedures for how a piece of research is conducted
• the experimental method involves the manipulation of an independent variable to measure the effect on the dependent variable to establish cause and effect relationships
• key features of the experiment :

  • controlled methods
  • random allocation of participants into controlled and experimental groups
• control group does not experience manipulation of IV (but to some extent)
• Independent variable -> condition A/ condition B -> (influences) -> dependent variable (measured)
• a variable is simply any factor that can vary or change within an investigation
• variables are used to determine if changes in one thing results in changes to another
• Independent Variable (IV) :

  • condition manipulated by the researcher
  • can change naturally
  • done so the effects on the dependent variable can be measured
• Dependent Variable (DV) :

  • measured by the researcher
  • any effect on the DV should be caused by the change in the IV
• Hypothesis :

  • a clear, precise and testable statement that states the relationship between variables to be investigated
  • is stated at the outset of any study
• Experiment :

  • an investigation in which a hypothesis is scientifically tested
  • advantage : experimental method should be objective
  • Researchers view and opinions should not affect a study's results
  • makes data more valid and less biased
• Aim :

  • a general statement of what a researcher intends to investigate
  • establishes the purpose of the study
  • aim of research are developed from theories
  • "To investigate…"
• Hypothesis :

  • statement made at the start of a study
  • clearly describes the relationship between variables stated by theory
  • hypothesis can be directional or non directional
• Directional Hypothesis :

  • researcher makes clear the sort of difference that is anticipated between two conditions or two groups of people
  • include words such as : less/more , higher/lower , faster/slower
• Non directional Hypothesis :

  • simply states there is a difference between conditions or groups of people
  • nature of the difference is not specified
  • use the word "…difference in …."
• Psychologists tend to use a directional hypothesis when findings of previous research suggest a particular outcome
• Psychologists use non directional hypothesis when :

  • there is no previous research
  • or findings from earlier studies are contradictory
• variables such as social behaviour, intelligence or thinking are often difficult to define and measure
• in any study, one of the main tasks is for the researcher ro ensure that variables being investigated are as measurable as possible
• Operationalised Variables :

  a variable is defined by the researcher and a way of measuring that variable is developed for the researcher
• operationalisation is not easy and care must be taken to ensure that the method of measurement gives a valid measure for the variable
• Methods to measure difficult variables :

  • frequency of something occurring - tally chart
  • time taken to do something
  • group categories
  • scales
  • questionnaires
  • observing behaviour
• the type of data collected depends on the type of research that is conducted
• The differenct types of data is :

  • Qualitative
  • Quantitative
  • primary
  • secondary
  • meta analysis
• Qualitative Data :

  • in form of words - rich in detail
  • produced from case studies, unsaturated interviews and observations
• Quantitative Data :

  • in the form of numbers
  • produced from lab experiments or closed questions (eg yes or no Qs)
• qualitative and quantitative data can overlap (eg interviewing participants who have taken part in a lab study)
• EVALUATION of Qualitative Data :

  + properly reflects human experiences and behaviours - so has higher internal validity than quantitative data

  • difficult to analyse and draw conclusions from
  • more open to bias and subjective opinion
• EVALUATION of Quantitative Data :

  + easier to analyse and draw conclusions from

  + less open to bias and subjective opinion

  • less rich in detail - doesn’t properly reflect human experiences and behaviours
• qualitative data is also known as non-numercial data as it does not contain numbers but words or vocabulary instead
• quantitative data is also known as numerical data as it involves numbers (can be counted)
• Primary Data :

  • data collected by the researcher for the purpose of the study
  • used when conducting interviews or running lab experiments
• Secondary Data :

  • data collected by someone other than the researcher (already exists) - eg censuses
  • researcher uses this data part of their study - but information not collected for the purpose of that study
  • eg meta-analysis study
• Meta analysis = when researchers looks at the results of a number of studies on a particular topic in order to establish general trends and draw conclusions
• EVALUATION of Primary Data :

  + usually designed for a specific study the researcher has control over it

  • requires more time
  • requires effort from the researcher
• EVALUATION of Secondary Data :

  + less time consuming

  + less expensive

  • quality of the data cannot be controlled by the researcher
  • the data used may not perfectly match the needs/ aims of the study
• EVALUATION of Meta-analysis :

  + reflects a potentially very large sample - makes easier to generalise (population validity)

  • may be a variance in the quality of the studies
  • may be the studies that are included re because they show significant results - may choice to ignore/ not include studies that wouldn't validate their findings (lack validity)
  • does not consider all the studies which may not have shown no significant result