AS + A2 Research Methods (Paper 2) Flashcards
Independent variable
The variable which is deliberately altered/ manipulated to see what its effect is.
Dependent variable
The variables in which changes occur due to independent variables .i.e. what is being measured/recorded.
Extraneous variables
these are variable that could interfere with the measuring of the IV and can be subdivided into participant variables and situational variables. Participant variables are any individual differences between participants that may affect the measuring of the DV e.g. personality, age whereas situational variables are any features of the experimental situation that may affect the DV.
Confounding Variables
these are variables that actually interfere with the measuring of the DV e.g. imagine you are doing an experiment on the effects of a new energy drink on levels of talkativeness – you pick 20 participants, 10 will consume the new energy drink and the other 10 will consume water only. You them measure how much both groups of participants talk for the next hour. Imagine group A (the energy drink group) are all extroverts and group B (the water group) are introverts. You will find that all the participants in group A talk much more than participants in Group B. However, was this due to the drink or the fact that all participants in group A were extroverts – thus personality now becomes a confounding variable
Laboratory experiments
Research is carried out in a controlled way.
The aim is to control all variables except one key variable, which is deliberately altered/ manipulated to see what its effect is.
For an experiment to be successful, the dependent and independent variables must be operationalised .i.e. clear, specific and testable. For example, if measuring aggression in children this must be testable .e.g. the number of times the child shows displays a verbal or physical act of aggression in a 10 minute period.
There may also be confounding variables which the experimenter will try and control such as noise, light etc
The aim of controlling EVs is to minimize their possible impact on the results of the investigation. An example of extraneous variables may be the participant’s personality or personal experiences
Laboratory experiments are conducted in an artificial setting.
Laboratory experiments advantages
Control- the effects of extraneous variables are minimized, so the experimenter can be more confident that is the independent variable which has affected the dependent variable.
Replication- strict controls means it is easier to replicate the study to test to reliability of findings.
Cause and effect – the cause and effect can be determined since the cause would be the IV and effect would be DV
Laboratory experiments disadvantages
Lack of ecological validity- because the setting is artificial, experiments may not be a reflection of real-life behaviour.
Demand characteristics- participants may either accurately or inaccurately guess the aim of the experiment and respond and behave according to what they think is being is investigated.
Field Experiments
Behaviour is measured in a natural environment like a school or street. The independent variable is manipulated by the experimenter (i.e. participants are put into conditions) so that its effect can be measured through the dependent variable
Field Experiments advantages
Ecological validity- field experiments are less artificial than those done in a laboratory, so they relate better to real life.
Demand characteristics- these can be avoided in a field study if participants aren’t aware that they’re in a study.
Cause and effect can still be determined since the manipulation of the IV is the cause and the measuring of the DV is the effect
Field Experiments disadvantages
Less control- it is harder to minimize extraneous variables in a field study, making it harder to come to a conclusion. Also less control over the sample (people being used in the experiment)
Ethics- participants who didn’t agree to take part might experience distress and can’t be debriefed. Observation must respect privacy.
Harder to replicate fully – because this is being carried out in the real world, you will never get the same sample.
Natural experiments
A natural experiment is a study that measures variables that aren’t directly manipulated (caused) by the experimenter, for example comparing behaviour in a single-sex and mixed school. This then means that the IV is naturally occurring. Effectively the experimenter is finding participants who already meet the conditions of the experiment, rather than allocating participants to conditions themselves.
Natural experiments advantages
Ethics - makes it possible to study variables that it would be unethical or impossible to manipulate e.g. comparing schizophrenic to non-schizophrenic individuals or comparing a community that has TV with a community that doesn’t to see which is the most aggressive
High level of ecological validity – because the experiment is carried out in a natural environment and the IV is not manipulated but naturally occurring, this allows for natural behaviour to be measured
Natural experiments disadvantages
Participant allocation - you can’t randomly allocate participants to each condition, and so extraneous variables (e.g. what area the participants live in) may affect results making it very difficult to reach conclusions.
Rare events - some groups of interest are hard to find e.g. a community which doesn’t have TV
Quasi-Experiment
This is very similar to a natural experiment in that the Independent Variable is not directly manipulated. However, Quasi experiments are generally carried out in a lab setting. An example of a variable that cannot be directly manipulated but can still be carried out under controlled conditions is gender – to test gender differences in memory
Quasi-Experiment advantages
Control - the effects of extraneous variables are minimized, so the experimenter can be more confident that is the independent variable which has affected the dependent variable.
Replication - strict controls means it is easier to replicate the study to test to reliability of findings.
Quasi-Experiment disadvantages
Lack of ecological validity - because the setting is artificial, these experiments may not be a reflection of real-life behaviour.
Demand characteristics - participants may either accurately or inaccurately guess the aim of the experiment and respond according to what they think is being is investigated.
Randomisation
The use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions. For example, to make sure that a list of words are not too easy or too hard, it is a good idea to put them in random order which can be done through a computer or manually.
Standardisation
Using exactly the same formalised procedures and instructions for all participants in a research study – this improves the reliability of the study (the ability to repeat the study again and get the same findings)
Independent groups design
This is where there are different participants in each group/condition. In other words, there are a different set of participants in all the conditions. Normally (but not always) an independent groups design is used to compare gender differences, age differences or any differences between people. But the participants only do the condition once, this avoids the problem that if all the participants did the test in both conditions any improvement in performance may be due to them having had a second opportunity to complete the task (which would be an extraneous variable).
Repeated measures design
This is where the same participants are used in each condition. The researcher can therefore compare the performances in each condition knowing that the differences weren’t due to participant variables (in other words, one group of pps were not better than the other as in an independent groups design) An example of an experiment when a repeated measure design could be used when we are comparing the performance of our pps when in condition A – they have consumed and energy drink and after some time interval e.g. a day, the same pps are tested but this time, they are given water. This allows for direct comparisons to be made without worrying about extraneous variables such as one group better than the other as would be the case in an independent groups design.
Matched-pairs design
This is where there are different participants in each condition, but they are matched on important variables (e.g. age, sex and personality, IQ). This then allows comparisons to be made but without one group just being better than the other since the participants in each group have been matched with each other so that participants in group A are equally matched with participants in group B. A matched pairs design avoids order effects as well as less chance of demand characteristics.
Control groups
Some studies use control groups. These are groups which have not experienced any of the manipulations of the IV that the experimental group might have. This allows the researcher to make a direct comparison between them in order to assess the impact of the IV.
Independent groups design advantages
No order effects through either getting better through practice (learning effects) or getting worse through being bored or tired (fatigue effects)
Less likely to guess the aim of the experiment and change behaviour to please the experimenter (demand characteristics).
Independent groups design disadvantages
Participant variables - Differences between people in each group may affect the results e.g. one group may just happen to be composed of individuals who have a better memory
Twice as many participants are needed to obtain the same amount of data compared to having everyone do both conditions.