These findings demonstrate that, there is a clear association between stress and lowered immune response, although this may have been due to other stressors involved and can lead to the suppression of the immune system. For this reason critics argue that the taking of the blood sample itself maybe a cause for stress in the students meaning that the procedure was a confounding variable and so could be the cause for the stress foremost and so effected the outcomes. Furthermore, using questionnaires may inhibit social desirability bias and so effect the students answers when answering particular questions thus, the data maybe false which would affect the results. However, critics are quick to point out that as they took a blood sample from each individual student twice, they were able to compare the results with each individual and not one another and so created more accurate liable findings.
Moreover, the studies of Riley indicate that his link between stress and other psychological states conveyed other aspects. As he induced cancerous cells into the brains of mice and placed them upon a rotating table. Consequently, producing stress in the mice resulting in some deaths. Subsequently his findings show that the results had a correlation. Yet the aspect of extrapolation comes from his study only being conveyed on mice and so can not generalise or be entirely linked with humans. Therefore, the results are hard to distinguish to that with humans. However, some would argue that human studies do in fact show similar results with that of Riley’s study and so extrapolation is not all accounted for as it does shoe some accuracy. In contrast to, the entire study was not ethical as it took animals and induced brain tumours into them causing death and so was not humane to pursue.
Whereas, other studies specifically Cohen, aimed to investigate the link between stress and immunosupression. He gave his volunteers 5 strains of the common cold via nasal drops. They were then monitored in secure housing for several days to see who developed a cold. They were also given a questionnaire to see how stressed they were. He found that a third of the participants developed a cold out of 394. There was a positive correlation between the stress levels and developing a cold. Participants with a high stress score were found to be twice as likely to develop a cold as others with a low score. Also, those who felt they were in control of their lives were significantly less likely to develop a cold than others who had an uncontrollable life.
Again due to questionnaires being given participants may have interpreted them and so social desirability bias may have an affect on the results as they would not be true and so cause results to be false and show invalid findings. Although critics are quick to point out that, as the procedure was done via nasal drops this reduces the likeliness of further stressors for example confounding variable as it does not cause a large amount of stress and anxiety due to this we know that the results were more obtainable and precise. On the other hand, due to the participants being monitored in secure housing this may have alarmed them and increased their stress levels as this can be seen as un- natural and so affected the results as the stress may be due to the surroundings and not what is being studied. Equally, the study’s findings show a positive correlation between the stress levels and immunosupression but this is not entirely the true cause as it is not definite but does in fact indicate that suppressive effects do lead to diseases yet is not the total cause for this.
Overall, it can be seen that the effect of stress on the immune system can be caused by numerous responses yet there is no definite answer for it yet research gives an insight to what may be the cause of this whether it the immune system itself or a confounding variable. They all add to the effects which may lead to infections, diseases or viruses.cv
