Demystifying Research for Medical and Healthcare Students. John L. AndersonЧитать онлайн книгу.
the box to the other. The escape group and the no‐noise groups easily learned to escape the noise by ‘shuttling’ their fingers. The yoked group, however, failed to escape and avoid the noise: ‘Most sat passively and accepted the adverse noise’.
Note the sophistication of this design. Both the experimental group and the yoked group got exactly the same amount of the stressor (noise). The only difference was that the experimental group could control the situation – the yoked group could not. And the control group were not exposed to the stressor at all. Thus, any differences between the experimental group and the yoked control group could not be attributed to different exposures to the stressor. And the no‐noise control group acted as a group who received no stressor – that is, they acted as a group to check for any Hawthorne Effect!
Note about Giving Electric Shocks to Student Subjects in Research
It used to be widely accepted that low‐level electrical shocks which were painful, but did not cause actual damage, were permissible in research studies. When I started studying Psychology at Aberdeen, the former professor had been very much into research on learning. Legend has it that he gave his research subjects higher and higher levels of electric shocks in his experiments, until they began to refuse to take part in his research – even though it meant having to fail to meet the course requirements to take part in at least three experiments! So research which involved giving electric shocks to subjects was stopped.
Seligman's work developed further to use the four‐button board with a green light and a red light. The green light signalled success and the red light signalled failure after each burst of the noise. Twenty sets of white noise at 110 dB in 30 second bursts were the aversive stimuli. Students were allocated to an experimental group and a control group. All subjects were instructed that by pushing the buttons in the correct sequence they might stop the noise. If they got it right, the noise would stop and the green light would come on. If they did not get it right, the noise would not stop and the red light would come on. In the experimental group, pushing any button four times would stop the noise and the green light would come on to signal success. In the (helpless) control group, no matter which button was pushed in any sequence or in any number of times, the noise would not stop and the red light would come on to signal failure. After the trial, subjects were tested on simple cognitive tests – anagram solving and arithmetic tasks. Those in the experimental group did better than those in the helpless/control group at solving the tasks. In addition, those in the helpless/control group seemed to lose heart and give up trying to solve the tasks more than those in the experimental situation. He noted that learned helplessness, sapped the motivation to try; it had cognitive impairments, and it had affective (emotional) impairments.
Example 2: My Own Experiment
I have always been very impressed by Martin Seligman's work and was eager to do my own research on helplessness. So, when I was at the University of Hong Kong in the 1980s, I informed my staff in the Behavioural Sciences Unit in the Faculty of Medicine of my interests. Within a month, half of them had started doing their own work to replicate Seligman and Hiroto's work! My interests were in people's lifelong exposures to helplessness and how these might contribute to helpless characteristics – with the possible implications for survival from cardiovascular diseases and cancers. So, I set out on my quest. I was on ‘long leave’ in London. I had the necessary equipment built – a computerised control box, a set of headphones, and a four‐button board. I made announcements to medical students and asked for volunteers for my pilot study. I vividly remember my first two subjects.
The first was in the control group – no matter what buttons he pressed, or in what order, or how many times, the noise could not be turned off and the red light would come on to signify failure. I remember him on the last of the 20 trials; he was bashing away at the buttons, frantically trying to find the correct sequence. Afterwards, I interviewed him about his life history of feeling in control or helpless. He was what you could call a ‘straight A student’. He had five As or A*s in his A levels. He had never failed an exam in his life. He could never recall or imagine a situation in which he would not succeed. He said to me, ‘Gosh, John, that was a really interesting trial. I know I didn't get it right in the time, but, I reckon that, with a few more goes, I could have got it right!’ I de‐briefed him about the experiment.
The second subject was in the experimental group. By pressing any button four times he could stop the noise immediately. He learned very quickly how he could stop the noise. I remember him on the last of the 20 trials; he looked fed up. As soon as the noise started be quickly pushed a button four times and the noise stopped. Afterwards, I interviewed him about his life history of feeling in control or helpless. He was also what you could call a ‘straight A student’. He had five As or A*s in his A levels. He had never failed an exam in his life. He could never recall or imagine a situation in which he would not succeed. He said to me, ‘I'm sorry, John, that was a real disappointment. I know that I could stop the noise by pushing a button four time. But it can't be as simple as that, so I don't feel that I really got it right – I didn't understand it!’ I de‐briefed him about the experiment.
This confirmed to me the importance of checking with experimental subjects what they think is going on in the experiment. The first subject felt that he was in control – even though he was in the ‘helpless’ group. The second subject thought he was helpless – even though he was in the ‘control’ group! The difference between them was the sense they made of the trial – how they attributed their part in the trial. Interesting, isn't it? But before I could complete my study, two things happened: (i) my equipment broke down and could not be repaired; and, more disappointingly to me, (ii) Martin Seligman and Judy Garber published their book Human Helplessness: Theory and Applications, in which they expounded in great detail an attributional analysis of learned helplessness – just the sort of thing I believed I had discovered!
Randomisation
Randomisation in experimental designs refers to the process by which your research participants are allocated to one group or another. (It does not, as some people think, refer to the recruitment of the sample.) The idea is that, by assigning participants to groups entirely by chance, this will avoid any bias or preference by the researchers. It is a means of ensuring equity, or fairness, in the distribution of participants to groups. Successful randomisation will ensure that each group of participants is roughly equal in characteristics, and should be roughly equal in their chances of performing in any tasks or tests they are given. When I started out as a researcher, we used to have ‘tables of random numbers’ which we had to refer to for allocations. Nowadays it is all done by computer, and quite rightly so. Never trust any method of randomisation which a human being can control or influence!
To Sum Up
First: you state clearly what you intend to do and why – including your hypotheses – if any. At this point, consider whether your study will be a single‐arm experiment or whether it will have more arms?
1 Then you decide who, or what, you want to include in your research, and how you will recruit them.
2 Next, if you have more than one arm, you should randomly allocate your research participants, or ‘subjects’ to the different groups.
3 You conduct the experiment and you note the results.
4 You analyse your results.
5 You disseminate your results by presenting the findings at conferences, or by publishing them in a book or in professional journals.
So, in Hiroto's and Seligman's work, their goals were clearly stated and linked to earlier work. They recruited an appropriate number (96) of psychology students and randomly allocated them to one of the three groups – the ‘control’, the ‘yoked control’, and the ‘helpless’ groups. They began the experiments by the ‘pre‐treatment’ helplessness testing/treatment. Then they tested the subjects' abilities