Experimental Methods

• define the term aim

  ->it's a general statement of what the researcher intends to investigate (the purpose of the study)
• define the term independent variable

  ->it's the variable manipulated

  ->has at least two conditions, often more, which can be assigned to different groups of participants, or used at different times
• define the term dependent variable

  ->it's the variable measured

  ->it needs to be quantifiable and preferably measured in some sort of standard unit
• what is the advantage of controlling the IV, DV and environment?

  we can safely say there is a cause and effect relationship and if we have a control group, we can then compare our experimental group with them to see what effect the IV has on the DV
• define the term operationalisation

  ->it involves clearly specifying and defining observable behaviours that represent the more general construct under the investigation to be measured
• define the term hypothesis

  ->it's a clear and precise prediction about the difference or relationship between the variables in the study
• what are the two different types of hypothesis

  ->directional hypothesis

  ->non-directional hypothesis
• define the term directional hypothesis

  ->also known as one tailed is one in which the hypothesis states the direction of results, it often use words like higher/lower
• define the term non-directional hypothesis

  ->also known as two tailed, it's a type of hypothesis where the direction of results isn't states

  ->it just says there is an effect but not what it is
• what makes an hypothesis directional?

  ->it states the direction

  ->there have been previous research implying a particular outcome
• what makes an hypothesis non-directional

  ->lack of previous research or findings

  ->or, they may have been previous research but they are contradictory
• define the term pilot studies

  ->small-scale prototypes of a study that are carried out in advance of the full research to find out if there are problems with the experimental design, instructions for participants and measuring instruments
• what is the purpose of carrying out a pilot study

  ->it's done beforehand to ensure time, effort, and money aren't wasted on a flawed methodology
• what are the four types of experiments?

  ->natural

  ->field

  ->lab

  ->quasi
• define the term lab experiment

  ->it's an experiment that takes place in a controlled environment in which the researcher manipulates the IV and records the effect of the DV

  ->it does this while maintaining strict control of extraneous variables
• describe the term field experiment

  ->an experiment that takes place in a natural setting within which the researcher manipulates the IV

  ->the effect of the DV is recorded as well
• define the term natural experiment

  ->an experiment where the change in IV is not brought about by the researcher but would have happened even if the researcher had not been there

  ->the effects of the DV's measured
• define the term quasi experiment

  ->a study that's almost an experiment but lacks key ingredients

  ->the IV has not been determined by anyone (the researcher or any other person)

  ->the IV is an existing difference between people (such as age/gender)
• what are the strengths of lab and quasi experiments?

  ->there's a high control over variables: this allows us to draw conclusions that the IV caused a change in the DV & it has a high internal validity

  ->replication is possible due to the high levels of control, this means we can check the validity of the results, and ensures they are not just a 'one off'
• what's a weakness of lab experiments

  ->it lacks generalizability: the environment is artificial and not like everyday life, & the participants may behave in unusual ways and therefore their behaviour cannot be applied beyond the lab setting (low external validity)
• what are other weaknesses of lab experiments

  ->usually, the participants know they are being a tested, so, they are subject to demand characteristics

  ->the actual task they do is often unlike real life and this means they lack mundane realism
• what is a strength of field experiments

  ->has higher mundane realism because the tasks tend to be more like what they would do in real life

  ->also, less controlled so behaviour more realistic
• what is another strength of field experiments

  ->behaviours is more natural due to the fact that the participants aren't aware of the fact that they are being studied which gives it a higher external validity
• what is a weakness of field experiments?

  ->less controlled which means a higher chance of extraneous variables affecting the DV, rather than just the IV

  ->this makes it slightly more difficult to establish cause and effect
• what's another weakness of field experiments?

  ->replication isn't possible due to low level of control and we can't check the validity

  ->also, ethical issues are also a problem- due to informed consent and privacy
• what's a strength of natural experiments?

  -provides opportunities for studies that would otherwise not be possible to research, mainly due to ethical reasons

  ->High external validity- real life situations without manipulation
• what are the weaknesses of natural and quasi experiments?

  ->naturally occurring events happen rarely, which limits the scope for research

  ->rare events mean it's difficult to generalise findings to other similar situations

  ->participants cannot be randomly allocated conditions which means we can be less sure whether it was the IV affecting the DV
• define the term experimental design

  ->the way in which the participants are 'organised' into groups in an experiment
• what are the three types of experimental design?

  ->independent groups

  ->matched pairs

  ->repeated measures
• independent groups

  ->it involves different groups of participants in each condition of the experiment

  ->it may consist of a control condition and one or more experimental conditions
• matched pairs

  ->this involves different groups of participants in each condition of the experiment

  ->however, each participant in the first condition of the experiment is matched closely with another participant in the second condition on all the variables considered to be relevant to the experiment
• repeated measures

  ->it involves the same group of participants in each condition of the experiment
• what are the strengths of repeated measures

  ->fewer participants are required since only a few are taking part in all conditions-less costly & time consuming

  ->the use of the same participants reduces the possibility of participant variables such as individual differences playing a part in the different results obtained- the effect on the DV can be attributed to the IV with more confidence
• what are the weaknesses of repeated measures

  ->as the same participants partake in both conditions of the experiment- order effect can occur

  ->participants who experience practice effects may perform better in the second conditions as they know what's expected of them

  ->participants who experience boredom/fatigue may perform worse in the second condition, due to giving up
• how do researchers address the issue of participants experiencing fatigue/boredom and performing worse in the second condition in a repeated measure experiment?

  ->they use counterbalancing which offsets any order effect
• what are the strengths of using independent measures?

  ->order effects cannot be observed as no participants will be used in more than one condition

  ->data collection will be less time consuming, if all conditions of the experiments can be conducted simultaneously
• what are the weakness of using independent measures

  ->different participants need to be recruited for each condition- it can be difficult and expensive

  ->there's a risk of participants variables (individual differences between participants) which affects the results between conditions, rather than solely manipulation of the independent variable
• what are the strength of using matched pairs

  ->because the researcher pairs up the participants so that each condition has people with similar abilities & characteristics- this reduces participants variables

  ->order effects (e.g, practice/fatigue) are less of an issue compared to a repeated measures design as the participants only take part in one condition of the experiment & therefore, they are less likely to become bored and give up
• what are the weaknesses of using matched pairs

  ->more participants are required, as different participants take part in the different conditions of the experiment, making the design more expensive & time consuming for the researcher

  ->furthermore, it's very difficult, if not impossible trying to find close/ exactly matched pairs

  ->which means that individual differences of the DV reducing the certainty that the IV affected the change
• define the term extraneous variables

  ->unwanted factors in a study that, if not accounted for, could negatively affect (i.e confound) the data subsequently collected