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Research methods - Coggle Diagram
Research methods
Control of variables
Extraneous variables - Any variables that may interfere with the IV or DV should be removed. These are known as extraneous variables. Where possible these should be identified at the start of the study, and researcher should try to minimise their influence
Confounding variables - These variables change systematically with the IV. Personality is a confounding variable. If our extravert types have been spread evenly between the two groups it wouldn't matter. The problem is if the extraversion varies systematically with the IV and this alone could explain changes with the DV
Demand characteristics - In research, ppts will try to work out what is going on. Certain clues may help them interpret what is going on. These are known as demand characteristics and may help the ppts to 2nd guess the experiementers intentions as well as the aims of the study. Ppts may slo look for clues to tell them how they should behave. They may act in a way they think is expected, over-perform to please the experimenter or they may under-perform to sabotage the results of the study
Investigator effects - Participant reactivity also leads to investigator effects. Investigators may act in a different way with both conditions to ensure that they get the result they desire eg. smiling more, unconscious cues, leading questions
Randomisation - Steps that the researcher can take to minimise the effects of confounding/extraneous variables on the outcome. Randomisation refers to the use of chance wherever possible to reduce the researcher's influence on the design of the study. Attempt to control investigator effects
Standardisation - All ppts should be subject to the same environment, information and experience. Therefore all procedures are standardised (written down) to say what exactly needs to be done in the study. This includes standardised instructions that are read to each ppt
Experimental method
Aims of research are developed from theories. They are general statements that describe the purpose of the investigation
Hypothesis - a statement that is made at the start of a study and clearly states the relationship between the variable as stated by the theory
Directional hypothesis - The researcher makes clear the sort off difference that is anticipated between two conditions or two groups of people ---> used when the findings of previous research studies suggest a particular outcome
Non-directional hypothesis - `states that there is a difference between conditions or groups of people but, the nature of the difference is not specified ---> When there is no previous research or findings from earlier studies are contradictory
Independent variable - researcher changes or manipulates this --> There are 2 levels of the IV: The control condition and experimental condition
Dependent variable - Measures the effect of the change of this variable
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Experimental design
Independent groups - When two separate groups of ppts experience two different conditions of the experiment.
- one group of ppt in experimental condition and one group of ppts in control condition. There performance of the two groups are then compared
Evaluation - the biggest problem is that the ppts who occupy the different groups are not the same. The results may be due to individual differences. To deal with this problem researchers use random allocation. Independent groups designs are also less economical than repeated measures as each ppt contributes to one result only. Twice as many ppts would be needed to produce equivalent data to that collected in repeated measures
The strengths are that order effects are not a problem whereas they are a problem for repeated measures. Ppts are also less likely to work out the aim of the study
Repeated measures - Ppts experience both conditions. 2 set of data would then be compared to see if there was a difference
Evaluation - Each ppt has to do at leats two tasks and the order of these tasks may have an effect (order effect). To deal with this researchers use counterbalancing (half ppts to condition A first, half ppts do condition B first). Creating two tasks could create boredom or fatigue so performance may deteriorate in 2nd task. Alternatively, ppts performance may perform better in the 2nd task due to the effects of practice. It is also more likely that ppts will work out the aim of the study. Therefore, demand characteristics tend to be more of a feature of repeated measures
The strengths are that ppts variables are controlled and fewer ppts are needed
Matched pairs - Ppts are paired together on a variable or variables relevant to the experiment. Then one ppt from each pair would be allocated to one of the different conditions
Evaluation - Ppts take part in a single condition so order effects and demand characteristics are less of a problem. Although there is some attempt to reduce ppt variables, there will still be important differences between them which may have an affect on the results. Matching may be time consuming and expesive, particularly if a pre-test is required so this is less economical than other deisgns
Field experiment
Strengths - Higher mundane realism as done in natural setting. Produce behaviour that is more valid and authentic. Ppts more likely to be unaware that they are being studied (high external validity)
Limitations - Loss of control of extraneous variables, cause and effect may be much more difficult to establish, precise replication is not possible. Ethical issues of informed consent and privacy
Natural experiment - Researcher takes advantage of a pre-existing independent variable. It is the IV that is natural, not necessarily the setting
Strengths - Provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons eg. orphan studies.Often have high external validity as they involve the study of real-life issues and probelms
Limitations - A naturally occurring event may happen very rarely, which limits opportunity for this kind of research. This may also limit the scope for generalising findings to other similar situations. Another problem is that ppts may not be randomly allocated to experimental conditions. This means that the researcher may be unsure of whether the IV affected the DV. eg. romanian orphan studies, those who were adopted late may have just been less attractive so no one wanted to adopt them
Lab experiment
Strengths - have high control over extraneous variables, therefore we can be more certain about demonstrating cause and effect (high internal validity). Replication is more possible than other experiments because of the high level of control. this ensures tat new extraneous variables are not introduced when repeating the study. Replication is vital to check the validity of the study
Limitations - May lack generalisability, articfical and not like everyday life. In an unfamiliar context, ppts may behave in an unusual way so their behaviour cannot be vernalised beyond the research setting (low external validity). Ppts may become aware they are being studied --> demand characteristics. Tasks ppts used to do do not replicate real-life (lack mundane realism)
Quasi experiments - have an IV that is based on an existing difference between people. No one has manipulated this variable, it simply exists. eg. anxiety levels of phobic and non-phobic patients were compared
Strengths - Carried out under controlled conditions so carry the strengths of a lab experiement
Limitations - Cannot randomly allocate ppts to conditions so there may be confounding variables