Bereavement includes grief, the psychological reaction of the individual, and mourning, the social expression of grief. 丧失包括悲伤，这属于个体的心理反应，还包括哀掉，这是悲伤的社会表现。
The discipline is a branch of psychophysics in that it is interested in the relation between sensory input stimuli and the behavioural or psychological response that they provoke. 这是一个精神物理学的分支学科，它侧重于研究感官的输入刺激和这些刺激所引发的心理反应或行为之间的关系。
