问题详情

Cohen and his colleagues had found in a previous study that happier people seemed less susceptible to catching a cold, but some questions remained as to whether the emotional trait itself had the effect.
For the new study, the researchers had 193 healthy adults complete standard measures of personality traits, self-perceived health and emotional "style." Those who tended to be happy, energetic and easy-going were judged as having a positive emotional style, while those who were often unhappy, tense and hostile had a negative style.
The researchers gave them nasal drops containing either a cold virus or a particular flu virus. Over the next six days, the volunteers reported on any aches, pains, sneezing or congestion they had, while the researchers collected objective data, like daily mucus production. Cohen and his colleagues found that based on objective measures of nasal woes, happy people were less likely to develop a cold.请帮忙给出正确答案和分析，谢谢！