When carrying out experimental research, one of the most important factors that psychologists have to consider is what variables need to be controlled and how that control is to be achieved. The study that I have chosen is Loftus and Palmer. Their experiment was on eyewitness testimony, and how reliable our memories really are. Controls used within this experiment were to prevent extraneous variables, as like in most experimental research.
Some of the controls that were accounted for were that the participants all viewed the same video, this was to ensure that all participants were given a fair chance, and they were all answering questions on the same piece of material shown to each participant. Another control was the location of the experiment. All participants were in the same environment/location (lab experiment), which meant that extraneous variables could not affect the experiment and give other participants an advantage over others.
All questions asked were the same (excluding the verb). As the question was kept the same it meant that some of the participants would not be asked leading questions or closed answer questions, which could in turn effect the results drastically. A control group was also used. This was in the second part of the experimental research. There were 150 students, who were shown a video and later were all asked questions, all but 50 students who were not questioned at all. This was the control group. The control group was used as a comparison group. Their answer to the question ‘Did you see any broken glass?’ was to be compared with those from the experimental group, who were asked questions about the video a week earlier.
The advantages to having students as participants is that there are always students around who are willing to proceed with these experiments, especially if there is money in hand. However this could demand the attention of ethics. Yet there is another disadvantage to having students as all the participants. It means that the researchers cannot generalise with the results that they have received. This is because all the participants are of the same age and there isn’t a variation within the group, which could change the results considerably.
Having all the participants contained in the same environment means that there aren’t any extraneous variables that could affect the research for some of the participants e.g. the weather. However the fact that the experiment is taken place inside-lab experiment means that there is low ecological validity. Meaning that it is not that true to life. The participants were watching a video of a car crash, so they were not actually at the scene of the incident.
However if they were to bare witness to an accident this could also stimulate the consideration of ethics. The fact that all the participants were asked the same question means that there weren’t any participants who were given a slight advantage, by having a different question (e.g. a leading question), causing an alteration within the results. However a disadvantage to the verb changing within the question for different groups is that some of the participants could just be giving an answer that would fit the researchers expectations. Demand characteristics. Which would mean that the results are not true results.
The same methodology was used for all the experiments, which would mean that all the participants were given a fair chance within the experiment. They were all tested equally e.g. they were all asked the same question. However the actual methodology could have a disadvantage. The fact that it was only students, who were used for the experiment and also the low ecological validity, could disrupt the process of the methodology.
If you do not use controls within you experiment, you may find that you end up with inaccurate results or the information given would be found irrelevant because you have not accounted for the controls. A variable that wasn’t controlled for in the Baron-Cohen et al experiment was the mental age and the chronological age of the children in the experimental groups. The mean verbal, mental age (vMA) of the autistic children was 5; 5 (5 yrs, 5 months), the mean chronological age (CA) was 11: 11. The downs syndrome vMA was 2: 11 and their CA was10: 2 and the ‘normal’ children had a mean CA of 4: 5, which was the same as the vMA. As we can see from the different groups the age differences are very different. If they had been controlled for they would have had either the same vMA or the same CA (more than likely the same vMA).
The problem with not controlling this variable is that the answers given cannot be related back to the lack of a theory of mind (ToM), as the autistic children have a higher vMA than the other experimental groups, therefore they have an advantage over the other children. Another variable that was not controlled for within the Baron-Cohen et al experiment was the size of the experimental groups. There were more ‘normal’ children (20) than both the autistic (27) and the downs (14) children. This would mean that the groups were not fairly tested and the answers of one group would have a larger percentage that another. As well as the varied size of the experimental groups they were rather small, which also means that the researchers were unable to generalise (accurately) with the results.
Within the Bandura, Ross and Ross investigations a variable that was not controlled for was the fact that one of the observers was the children’s nursery teacher, meaning that some of the observations could possibly be biased. Therefore the results wouldn’t be completely true, causing the end statement or theory to be inaccurate. Another variable within the Baron-Cohen et al study was that it was bias towards males, meaning that there were more males in the study than females. This could affect the study in that boys and girls may interoperate things differently and therefore the researchers could be generalising with the information given by mainly males.
A variable that wasn’t controlled for in the Loftus and Palmer study were the subjects. They were all students or all of the same age, leaving the researchers unable to generalise accurately. To have controlled this variable the researchers would have had to selected people due to their age, status, sex and ethnic background. There would also have to be a fair amount of people within each study, and the same amount of people with different characteristics.
This way the study can be seen upon as fairer, causing the researchers to generalise with more adequate results. If this had been controlled for the results could have been that women tended to pay more attention to detail, whereas males were liable to see something and then instantly forget it, it could however be the other way around. The outcome of the study could have been affected in that people of an older generation may not b able to note down every detail, as their sight is infallible, like everyone else, but more so them. However this could be seen as ageist. Variables must be controlled in order to have a fair experiment. They are also used to prevent extraneous variables, which could affect the study enormously. If the variables are all kept the same then accurate results are likely to be filed and the end results could have a great impact on the way society live and think.