research methods

• experimental method


  involves the manipulation of an independent variable to measure the effect on the dependent variable
• aim

  a general statement of what the researcher wants to investigate - starts with a "to see/find/investigate"
• hypothesis


  a clear, precise, testable statement that states the relationship between the variables to be investigated, stated at the start of any research
• null hypothesis


  a statement of no relationship/difference between variables
• alternative hypothesis


  states that there is a relationship/difference between variables, which attempts to show the null hypothesis is not supported
• directional hypothesis


  states the direction or difference or relationship, one-tailed
• non-directional


  does not state the difference, two-tailed
• independent variable


  an aspect of the experimental situation that is manipulated by the researcher, so the effect it has on the DV can be measured (overall, the one you change)
• dependent variable


  the variable that is measured by the researcher. any effect on the DV should be caused by the change in the IV. (overall, the one you measure)
• operationalise


  defining your variables how you intend to measure them
• extraneous variable


  a variable, other than the IV that might impact the results but do not vary systematically with the IV, so can be controlled before the experiment
• confounding variable


  a variable which might impact the results because it provides an alternative explanation as it may vary systematically with the IV
• types of extraneous variables


  participant variables, situational variables, investigator effects, order effects, demand characteristics, social desirability
• participant variables


  the differences between the people who take part in the study e.g. age, personality etc.
• situational variables


  features of the experimental environment that could affect the IV e.g. temperature, time of day, noise etc.
• investigator effects (researcher bias)


  an unwanted influence of the investigator on the research outcome. this might be an unconscious thing in which the investigator influences the results of the study unintentionally e.g. smiling every time the participant answers correctly
• order effects


  an extraneous effect that arises from the order in which conditions are presented e.g. becoming bored or tired and therefore under-performing
• demand characteristics 


  when participants work out the aim of the study and change their behaviour accordingly e.g. participants may over-perform to please the researcher or might deliberately underp

  -perform to sabotage the results
• social desirability 


  when people lie during research to please the researcher/when they give socially desirable answers to make themselves seem like a good person e.g. they may lie about alcohol consumption
• standardised procedures


  a set order of carrying out a study that is applied to all participants when necessary
• instructions


  the written or verbal information given to participants during the experiment
• random allocation 


  where participants are split into different group. this should be done randomly, such as through a random name generator or picking names out of a hat. this helps prevent the groups having people of similar characteristics. this helps control participant variables
• counterbalancing


  where participants take part in two conditions (i.e. in a repeated measures design). half the participants take part in condition A then B, and the other half does B then A. it does not remove or prevent order effects but it attempts to balance out the effects of order between the two conditions
• randomisation


  using chance to, wherever possible, reduce the researcher's influence on the design of the research. e.g. the order of a word list should be done via a random number generator, with each number representing a word. this controls the investigator effects (researcher bias)
• experimental design


  the different ways in which participants can be organised in relation to the conditions of an experiment
• condition


  an experiment is usually organised so that there are two trials/groups after which the performance of the participants are comapred
• independent groups


  two separate groups of participants experience two different conditions of the experiment
• adv. of independent groups


  there are no order effects (participants becoming bored, tired, or better) as they only take part in one condition. also, there are no demand characteristics (changing behaviour to please the researcher) as again they only take part in one condition
• disadv. of independent groups


  participants who occupy the different groups are not the same. if a researcher finds a difference between the groups, it may give an alternate explanation to their results, rather than the IV. the design is also less economical as each participant. contributes just one result
• repeated measures


  one group of participants experience all of the conditions of the experiment
• adv. of repeated measures


  there is no issue with participant variants because everyone is in the same group. this design is more economical as each participant contributes more than one result
• disadv. of repeated measures


  there are no order effects as they take part in more than one condition. the effects of the order of the tasks can be a confounding variable. there are demand characteristics as theyre more likely to guess the aim considering they experience all conditions
• matched pairs


  two separate groups of participants experience two different conditions of the experiment but are matched on a particular certain characteristic before the experiment takes place
• adv. of matched pairs


  there are no order effects or demand characteristics as they only take part in one condition. participant variables are reduced as participants variables are reduced as participants are matched based on their characteristics
• disadv. of matched pairs


  although there is an attempt to reduce participant variables, participants can never be matched exactly. matching participants is also time-consuming and expensive as it requires the researcher to test people before the study, meaning it is less economical
• ecological validity


  the results of the investigation can be said to apply to real-life behaviour as they are an accurate account of behaviour in the real world
• the 5 characteristics of a true experiment

  1. has an independent variable
  2. measuring a dependent variable
  3. have a control group
  4. random allocation is used
  5. data is collected to analyse if it fits the hypothesis
• laboratory experiment


  they are conducted in highly controlled environments where conditions are well-controlled. not always in an actual lab
• strengths of laboratory experiment

  • high control of CVs and EVs
  • effect on DV must be due to IV
  • high internal validity
  • replication is more possible
  • no new EVs when repeated, so findings are valid
• weaknesses of laboratory experiments 


  • lack generalisability
  • environment is artificial so behaviour may be unusual
  • low external validity
  • environment means participants are aware its an experiment so may show demand characteristics
  • unusual tasks mean low mundane realism