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.

• 科恩博士和他的同事在此前的一项研究中发现，比较快乐的人不易患感冒，但不能完全确定这一性格本身是否具有这种“功效”。