Sadness is a common experience in childhood. Some families may have a (conscious or unconscious) rule that sadness is "not allowed", but Robin Skynner has suggested that this may cause problems, arguing that with sadness "screened off", people can become shallow and manic. Pediatrician T. Berry Brazelton suggests that acknowledging sadness can make it easier for families to address more serious emotional problems.
Sadness is part of the normal process of the child separating from an early symbiosis with the mother and becoming more independent. Every time a child separates a little more, he or she will have to cope with a small loss. If the mother cannot allow the minor distress involved, the child may never learn how to deal with sadness by themselves. Brazelton argues that too much cheering a child up devalues the emotion of sadness for them; and Selma Fraiberg suggests that it is important to respect a child's right to experience a loss fully and deeply.
Margaret Mahler also saw the ability to feel sadness as an emotional achievement, as opposed for example to warding it off through restless hyperactivity. D. W. Winnicott similarly saw in sad crying the psychological root of valuable musical experiences in later life.
According to the American Journal of Psychiatry, sadness has been found to be associated with "increases in bilateral activity within the vicinity of the middle and posterior temporal cortex, lateral cerebellum, cerebellar vermis, midbrain, putamen, and caudate." Jose V. Pardo has his M.D and Ph.D and leads a research program in cognitive neuroscience. Using positron emission tomography (PET) Pardo and his colleagues were able to provoke sadness among seven normal men and women by asking them to think about sad things. They observed increased brain activity in the bilateral inferior and orbitofrontal cortex. In a study that induced sadness in subjects by showing emotional film clips, the feeling was correlated with significant increases in regional brain activity, especially in the prefrontal cortex, in the region called Brodmann's area 9, and the thalamus. A significant increase in activity was also observed in the bilateral anterior temporal structures.