During development we learn to filter out extraneous sensory input, and to focus on whatever is most important to us at that moment in time. The TV and washing machine are going, your spouse is gabbing, your children are cavorting about, but you are able to read your journal, because you have learned to selectively attend. In contrast, the infant is receiving stimuli from all senses simultaneously, but has not yet learned to focus her attention. She has not yet learned how to self-soothe, or even be soothed by others. Her cries of distress are ones of protest, but not pain.
Gastroenterologists tend to view colic as the earliest functional bowel disorder.
However, there is no objective data to suggest that intractable fussing without failure to thrive in the second through fourth months of life is associated with a bellyache or has anything to do with digestion. Infant colic may be confused with irritability from gastroesophageal reflux disease, milk protein allergy, or another illness, but illness should be associated with other signs and symptoms in addition to intractable fussing. The ability to soothe oneself or to be soothed by others may play an important role in coping with functional disorders throughout life. Individuals who have a defective coping style may utilize far more medical resources than those who cope well. A four year old girl was evaluated for fecal incontinence during seizures.