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Tuesday, November 9, 2010

Manipulation in Research

Manipulation in Research
In selecting an independent variable for any piece of research, we must first decide what we are interested in. For example, we might be interested in whether attributional style (the way people explain events) affects people’s responses to failure. We might hypothesize that people who tend to blame themselves for failure (i.e. those who internalize failure) are more likely to become depressed than people who blame their failure on other things (i.e. who externalize failure). So the central theoretical variable – the focus of our interest –is the participants’ attributional style. But, how can we manipulate this for the purposes of our experiment? Clearly we cannot open up people’s heads and turn a dial that says ‘attributional style’ to maximum or minimum. To get around such obstacles, psychologists usually manipulate the theoretical variable indirectly. They do this by identifying an independent variable that they believe will have a specific impact upon a given mental process, and then check that this is the case. In our example, the researchers may expose participants to failure (e.g. in a test) and then ask some of them to answer questions like ‘Can you explain why you did so much worse than everyone else?’ – questions that encourage the participants to reflect on their own contribution to their performance (i.e. to internalize). They may then ask other participants questions like ‘Do you think the fact that you were not allowed to revise for the test affected your performance?’ – questions that encourage them to reflect on the contribution of other factors to their performance (i.e. to externalize). To be sure that this manipulation has had the desired effect on the theoretical variable, the researchers may then want to perform a manipulation check. [manipulation check a procedure that checks the manipulation of the independent variable has been successful in changing the causal variable the experimenter wants to manipulate] For example, in the case given above, the researchers might measure whether the ‘internalizing’ question produces greater agreement with a measure such as: ‘How much do you think you were responsible for the test outcome?’ Note also the significant ethical issues relating to this study. The experimental manipulation could have the effect of making some participants more depressed – indeed, that is the hypothesized outcome in the condition where participants are encouraged to internalize their failure.

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