The aim of Weiss et al's experiment was to see if short term stress (loud noise and electric shocks) reduced the amount of T cells subsequently weakening the immune system. The experiment took place in a laboratory. The procedure measured T cells by taking a blood sample before and after being exposed to loud noise and electric shock. The findings of this experiment were that the T cell count in the 2nd blood test (after electric shock) was considerably less compared to the count of T cells before the electric shock. The conclusions we can draw from this experiment are that short term stressors reduce T cell count and so decreases immune function.
Both experiments use a blood sample which is objective, they also both use empirical methods which makes them both a valid scientific experiment. Both experiments are easily replicable which means they have high reliability.
Kiecolt-Glaser et al's experiment lacks population validity because all students are of similar age and have a high IQ. Different personality types go into different jobs meaning that you would only be looking at how one type of person reacts to stress. Another weakness of batman study is that it is likely to contain confounding variables such as the lifestyle changes you undergo through a stressful period such as smoking more often and eating unhealthy food. These confounding variables make it difficult to judge whether it is stress or the lifestyle changes that happen because of stress that decrease the T cell count.
The strengths of Kiecolt-Glaser et al's experiment are that it has ecological validity because it was observing a real situation unlike the robin experiment which took place in a laboratory and therefore does not reflect the real world and makes the findings difficult to generalise. The batman experiment also avoids ethical issues due to the stress happening anyway and not being provoked as part of the experiment.
The experiment done by Weiss et al has high internal validity because the independent variable (loud noise/electric shock) reflects the dependant variable (stress). We can be sure of this due to the fact that it was a highly controlled laboratory experiment.
Weaknesses of the Weiss et al experiment are the ethical issues. The purpose of the experiment is to create stress and the means of creating this stress could harm a participant and make them feel uncomfortable however this is overcome but the right to withdraw and being offered counselling for any distress caused.
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eljb29 (student)
