The theory of attachment is generally credited to British researcher John Bowlby, who developed it in the first half of the 20th Century, primarily in relationships of children to parents. Bowlby's attitudes were greatly influenced by his own childhood in a typical upper-middle class English family.
While still generally accepted today by the sociological community, his ideas of attachment styles in children, and in their later life as adults, are very narrow and very British. They are somewhat outdated in his native country, and for the past two generations, have evolved differently in the US.
Bowlby was brought up in a very strict household that was traditional in its privileged British class system of his time. His landowner and politician father was rarely at home, and his staid mother was a distant figure who spent very little time with him. He writes that his mother and father believed excess doting and physical love were actually detrimental to a child's emotional development. He was cared for from birth to adolescence by nannies, and in his writings, expressed a deep mother-child attachment to his first nanny.
Therefore, today's students of adult attachment theories must take into consideration the influences Bowlby's childhood had on his thinking and descriptions of his psychological approach to the subject. His basic theory goes back to pre-history, as well as to typical animal group behavior. Human attachments were evolved from the earliest family groups, and were essential to protect children from very real outside dangers, such as predators and natural dangers.
Attachment styles in adults progress from that atavistic need of infants to stay close physically and emotionally to their parents. Then, in the usual order, the infant evolves into a thinking child and reaches beyond the family for attachments. Peer friendships at play and school become important, and in most situations, the child will select a "best friend" for a closer and more supportive relationship. At that time, mother/father/sibling attachments become less important to the child.
Next, comes puberty and the further detachment, some benign and others more divisive, from family influences. It is often the most confusing stage of attachments, when the child's emotions are often torn between the deeply-ingrained relationships of family and the growing independence of social and sexual freedoms.
Adult attachments continue to be influenced by all that went before in the family, and like Bowlby's personal history, they are basic in forming lifelong behaviors. For instance, children who had tightly-binding relationships with mothers may find their adult attachments influenced both negatively and positively in seeking and establishing their own family structures. While most theories on adult attachments deal with affectionate relationships, children who grow up with a distant or abusive father may have to deal resentment and hatred throughout their lives. They must work to overcome those entrenched memories when they go on to establishing their own positive adult situations.
Adult attachments are lifelong challenges, including when they concern advanced old age. Adult children with their own families of dependent parents who need physical and/or financial support often face troubling dilemmas. Do they sacrifice time, love and resources away from their own children and spouses in order to fulfill the responsibilities and/or guilt they feel for their parents?