The systematic study of gratitude within psychology only began around the year 2000, possibly because psychology traditionally focused more on understanding distress than on understanding positive emotions.
在心理学层面对感恩进行系统性研究是在2000年左右才开始，可能是因为心理学历来更侧重于理解负面悲观情绪而不是理解积极的情绪。