Experiments

• What are the experimental methods?

  Lab, field, quasi
• What is a lab experiment?

  the IV is manipulated to measure the DV (effects on behaviour)

  all other variables (extraneous) are highly controlled and held constant e.g. noise, temperature

  the way participants are treated are con trolled by using standardised instructions
• What are the positives of lab experiments?

  P: standardised procedures (giving the same tasks/timings/instructions to every participant) allows replication, increases validity C: increases consistency

  P: high levels of control over EV‘s in order to determine cause and effect increases validity

  C: increases accuracy
• What are the negatives of lab experiments?

  P: high levels of control leads to artificial environment so ecological validity is reduced

  C: doesn't reflect real life behaviour in everyday situations

  P: demand characteristics - participants may act unnaturally as they know they’re taking part in an experiment. this reduces validity

  C: decreases accuracy
• What is a field experiment?

  The IV is manipulated and the DV is measured, however this takes place in a natural environment such as the participants home or place of work/study
• What are the positives of a field experiment?

  P: carried out in real life settings therefore high in ecological validity.

  C: reflects real life behaviour

  P: participants are in a natural environment so they don’t know they’re being studied (less chance of demand characteristic) this increases validity

  C: increases accuracy
• What are the negatives of a field experiment?

  P: natural environment leads to low levels of control over EV’s (extraneous variables) decreasing validity

  C: reduces accuracy
• What is a quasi experiment?

  The IV is naturally occurring and cannot be manipulated by the experimenter, the effect on behaviour is then measured.

  • E.g. autism, addiction
  • can take place in a field or lab setting
• What are the positives of a quasi experiment?

  P: able to investigate behaviours which could otherwise be impossible/impractical to investigate

  it does not breach ethical guidelines

  C: does not damage the reputation of psychology nor affect future funding and recruitment of participants
• What are the negatives of a quasi experiment?

  P: lack of control over individual differences, decreases validity

  C: reduces accuracy of behaviour
• What is the independent variable?

  The one you manipulate
• What is the dependent variable?

  The one you measure
• what is operationalising variables?

  Stating how the IV is being manipulated and how the DV is being measured
• What is an extraneous variable?

  An extraneous variable is inevitable and can include environmental conditions or characteristics of the task or participants.

  They should be kept the SAME for each participants regardless of IV conditions
• What is a confounding variable?

  A confounding variable is an extraneous variable that differs systematically across the conditions, changing the outcome of the experiment and causing you to wrongly estimate the relationship between the IV and DV
• Experimental (alternative) hypothesis…

  is what most research experiments start with
• alternative/experimental hypotheses can be..

  Directional (one tailed) or non-directional (two-tailed)
• What is a null hypothesis?

  We have to show that the null hypothesis can be rejected, only then can we accept the experimental/alternative hypothesis.
• What should a one tailed hypothesis start with?

  There will be a significant increase/decrease….
• What should a two tailed hypothesis start with?

  There will be a significant difference….
• What should a null hypothesis start with?

  There will be no significant difference…
• Within experimental methods, what are the three experimental designs?

  independent measures

  Repeated measures

  Matched pairs
• summarise independent measures design

  Different participants in each condition
• Summarise repeated measures design

  Same participants in both conditions
• Summarise matched pairs design

  Matches one participant in one experimental condition as closely as possible to another in the second condition e.g age, gender
• What are the advantages of independent measures design?

  P: no order effects (participants getting tired/bored) as they only experience one condition

  C: increases validity and accuracy
• What are the disadvantages of independent measures design?

  P: low levels of control over individual differences e.g someone may have more ability or age/gender

  C: reduces validity
• What are the advantages for repeated measures design?

  P: high levels of control over individual differences as each participant is compared to themselves

  C: increases validity as we can accurately measure (context)
• What are the disadvantages of repeated measures design?

  P: unable to use the same task in both/all measures e.g. list of words

  C: not cost or time efficient

  P: order effects as they’ve experienced both conditions, it can become better practiced or can perform worse due to boredom

  C: reduces validity as we’re not accurately measuring (context) what was intended
• What are the advantages of matched pairs design?

  P: high control over individual differences as each participant is matched on relevant criteria

  C: increases validity
• What are the disadvantages of matched pairs design?

  P: time consuming, if at all possible to match participants on relevant criteria

  C: waste of funding as it is costly

  P: can be subjective in the choice of relevant matching criteria

  C: reduces validity
• To reduce order effects when using repeated measures design, what technique is used?

  Counterbalancing e.g. the ABBA technique
• Structure for a 12 marker


  WHAT: define RF (required features)(one sentence)

  HOW: must be replicable and relevant to RF (operationalise IV and DV) Use given context

  WHY: Evaluate strength of RF via PEC structure using given context

  LINK: link comment from why to your own experiment (use own context) end with ‘This is why I will also be using…
• self-reports ➢ Participants are asked to report their own thoughts, feelings, and behaviors
• How can self-reports data be collected?


  Questionnaires or interviews
• Questionnaires are always structured and don’t change from person to person