Discuss the reliability issues of the experimental method

Discuss the reliability issues of the experimental method.

An experimental method is where the researcher manipulates an independent variable under controlled conditions in order to measure the effect on the dependent variable. It allows researchers to identify the differences between conditions. There are three main types of experiments these are, a laboratory experiment, a field experiment and a quasi experiment. Each have their own strengths and weaknesses.

Experiments are reliable as they use objectivity instead of subjectivity. Objectivity is not being influenced by personal feelings or opinions; only considering facts. This is what makes the experiment reliable. If there is no interpretation of any information gathered then there is no space for mistakes.

Unlike observations that use qualitative data, the experimental method only deals with quantitative data. Quantitative data is collected therefore only figures are collected and analysed to give a specific result. Quantitative data is easily repeated therefore making the experiment reliable.

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The researcher control’s the variables in order to get their quantitative data. For example Elizabeth Loftus’s independent variable was whether the man in the scene was holding a cheque or a gun. This is how she manipulated the variables and she then got the participants to fill out a 20 multiple question, questionnaire and then got them to identify the man holding the cheque or the gun from a line up of head and shoulder pictures. She measured the amount of eye focus on the gun or cheque and the amount of people who got the suspect wrong on each condition. This is how she measured the dependent variable.

The amount of people that got the suspect correct on the condition where the man was holding a cheque to the cashier was 38.9% and the amount of participants that got the suspect correct on the condition where the man was holding a gun was 11.1%. Also an average of 2.44 fixations on the cheque and an average of 3.72 fixations on the gun.

This proved her hypothesis right that weapon focus should be taken into account as peoples memory’s are affected by the stress of seeing a weapon.

As the experiment had quantitative data and the variables were controlled this makes the experiment reliable as you can repeat it again and again.

Although there are many aspects that make the experimental method reliable there are also a couple of things that can get in the way which would then make the experiment unreliable. One of these can be found in field experiments as there is less control over extraneous variables, due to the setting. Also if an experiment took place say within a hard to reach participant group there is no saying that this will be accomplished again.

Also by controlling the variables so much there can be complications as the results could come out differently than if they had not controlled the variables. For example the experiment by Dement and Kleitman on sleep and dreaming had this problem. Dement and Kleitman told their participants not to drink coffee or have any stimulants before they came in to the laboratory. But problem with this is that some of the participants may have a cup of tea or coffee before they go to bed at night. Also they aren’t sleeping in their own beds therefore they may not sleep as well as they would do in their own beds, therefore creating reliability and ecological validity issues.

Peer Reviews

Here's what a star student thought of this essay

sydneyhopcroft

25th of Aug 2012

Quality of writing

The Quality of Written Communication is excellent. There is no cause for concern either from a psychological perspective or an English one. The candidate uses a number of important psychology terms in order to express their analysis in the language of the professionals, and this indicates confidence and flair in the psychological analysis. There is also no cause for concern with regard to spelling, grammar and/or punctuation.

Level of analysis

The level of Analysis is more expected of a GCSE student than an A Level student. The is because the analysis is spread out irregularly throughout the answer with a random description of a study by Loftus in the middle. It would serve the candidate better to adhere to the layout I suggested earlier, as this would help them cover all the necessary information. I would also like to see more of an integrated analysis. The first to points raised show how this candidate could do this - instead of talking about the reliability of the methodology of experiments and then how the results of experiments include primarily quantitative data, link these two together - "A strength of experiments is that they usually collect quantitative data as opposed to more subjective qualitative data. The strength here is that because numbers are universal standards they can be statistically analysed without having to worry about personal interpretation or experimenter bias. he same can be said for the experiment's methodology - it is often unbiased due to the heavily controlled settings and predetermined conditions in which the experimenters aim to manipulate behaviour. So the overall strength is that experimenter bias can be ironed out with regards to methodology and the results. Integration like the above will help create a more smoothly-running answer that feels more confident to the examiner, who will then get a feel of the comfortability of the candidate and appreciate their knowledge and analysis more.

Response to question

The candidate here has made a good effort in trying to evaluate the reliability o f the experimental research method. They have consulted with empirical evidence from Elizabeth Loftus' study into weapon focus as a factor influencing memory, but I would argue the evaluation and overall discussion is slightly lacking in clarity and balance. Some examples of criticism and support for the research method are not structured as part of a cohesive segment of the essay, so the structure is a little slapdash. It would be better to provide an introduction and then the evaluation, integrating references to a variety of relevant studies in order to best achieve the maximum possible marks whilst covering all the important information.

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