Exam Stress (Kiecolt Glaser et al, 1984)

To investigate the effect of exam stress upon the immune system. 

Blood samples of 75 first year medical students taken. (1 month before first exam and on the day of first exam) 

• Level of killer T cells measured. 
• Questionnaires filled in to measure psychological factors, such as social support and life events

Fewer killer T cells found in the second sample than the first, especially when students reported loneliness and high numbers of life events. 

Even short-term exam stress can become damaging to health, especially when experiencing other stressors. 

• A natural experiment - high ecological validity.

• Cause and effect cannot be established 

• Measuring killer T cells is objective - investigator effects are not a problem 

• All participants were students, so results may not be generalisable

• HOWEVER, other studies have shown the same effects with different population groups.