The Experimental Method Flashcards
What is an aim?
general statement that describes the purpose of an investigation
what is a hypothesis?
a statement that is made at the start of a study and clearly states the prediction of the relationship between variables.
what is a directional hypothesis?
predicts the direction of the effect
what is a non-directional hypothesis?
states that an effect will occur
when do scientists usually use a directional hypothesis?
when the findings of precious research suggest a particular outcome
what is the difference between the IV and DV?
IV is what is changed or manipulated by the researcher
DV is what is measured by the researcher
what are the two conditions in an experiment?
control condition and experimental condition.
what does it mean for a hypothesis to be operationalised?
clearly defining variables in terms of how they are measured
what are extraneous variables?
Any variable other than the IV that may have an effect on the DV if it is noy controlled. They do not vary systematically with the IV.
what are confounding variables?
any variable other than the Iv which may have AFFECTED (past) the Dv so we cannot be sure of the true source of changes to the DV. Confounding variables vary systematically with the IV.
what are demand characteristics?
any cue from the researcher that may be interpreted by participants as revealing the purpose of the investigation- participants may change their behaviour.
what are investigator effects?
any effect of the researcher’s behaviour (conscious or unconscious) on the research outcome (DV)
what is randomisation?
the use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions
what is standardisation?
using exactly the same formalised procedures and instructions for all participants in a research study.
what is experimental design?
refers to the different ways in which the testing of participants can be organised in relation to the experimental conditions.
what is an independent groups design?
participants are allocated to different groups where each group represents one experimental condition
what is repeated measures?
all participants take part in all conditions of the experiment
what is a matched pairs design?
pairs of participants are first matched on some variables that may affect the DV. Then one member of the pair is assigned to condition A and the other to condition B.
what is random allocation?
an attempt to control for participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other.
what is counterbalancing?
an attempt to control for the effects of order in a repeated measures design; half the participants experience the conditions in one order and the other half in the opposite order
What are participant variables?
any individual differences between the participants that may effect the Dv e.g. age, ability, IQ
what are situational variables?
factors of the situation that may affect the DV e.g. noise, time of day
what are order effects?
when participants may perform differently the second time they do the task simply because it is the second time they have done it and not due to the IV
e.g. practise, boredom and fatigue
what are strengths of a repeated measures design?
- less participants needed
- no participant variables
what are limitations of a repeated measures design?
- order effects are a problem
- demand characteristics more likely
what are strengths of an independent groups design?
- no order effects
- demand characteristics less likely (because P’s only do 1 condition of the IV)
what are limitations of an independent groups design?
- participant variables
- more participants needed
what are strengths of matched pairs design?
- no order effects
- demand characteristics less likely
- participant variables reduced
what are limitations of matched pairs design?
- need information to match participants on
- pre-testing might be needed (expensive and time consuming)
how do we control for participant variables?
matched pairs
independent groups
random allocation
how to we control for investigator effects/ researcher bias?
randomisation and standardisation
what is a solution for order effects?
counter balancing
