There have been various studies into the effects of stress on the immune system. Kiecolt-Glaser researches this by looking at how quickly wounds heal. She used 13 women aged 47-81 who cared for Alzheimer’s and Dementia sufferers. They had naturally occurring high stress levels, and this is why she chose them. The women were matched with volunteers for maximum similarity (the matched pairs design). Kiecolt-Glaser tested all the women’s blood for the proteins which prepare the tissue for repair, called cytokines.
She then gave them a small wound on the arm to see how long it would take to heal. The results of Kiecolt-Glaser’s research showed that the carer’s wounds took 9 days longer to heal than the volunteers matched to them. Their Cytokine levels were lower and the stress scales showed they were the most stressed. This therefore shows that stress has a large effect on your immune system as the more you are stressed, the worse your immune system will work. This research method is good as Ecological validity is high because it is a natural study.
It is a natural study because the women carers’ stress levels were naturally high, instead of stress levels induces artificially by a researcher. (This experiment therefore has applications in the real world). A negative aspect of this research is that it crosses ethical issues such as; when the researcher gave the participants a small punch biopsy they were harmed, this may affect the credibility of the findings as some people believe the methods to be unethical and wrong.
Them being harmed most likely added to their stress levels also and so interferes with the investigation. As Kiecolt-Glaser only tested female carers in her experiment, it is therefore Gynocentric. Her results cannot be fully used to explain the relationship between stress and the immune system, as the findings cannot be reliably applied to men. Cohen also investigated the effects of stress on the immune system. Cohen studied how general life stress affected the participants’ vulnerability to the common cold virus.
The study was carried out as follows; 394 participants completed questionnaires about the stressful life events they had experienced in that year. They rated their degree of stress and levels of negative emotions such as depression. Cohen created a stress index from their combined three scores. They were then exposed to the virus and they found that 82 percent became infected with the virus. The conclusion was that chances of developing illnesses and fighting off viral infections, was significantly connected with stress index scores.
This research has methodological problems such as it does not show us which part of Cohen’s stress index is the most important when it is relating to the chances of developing infections. There were also no direct measures of immune function, so it was an indirect study. However other research supports Cohen’s, research that shows that the probability of developing a cold was significantly correlated with negative events in the days before.