There has been an enormous amount of research conducted about adopted children and their problems with identity formation. The National Adoption Center reports that fifty-two percent of adoptable children have attachment disorder symptoms. It was also found that the older the child when adopted, the higher the risk of social maladjustment. This is to say that a child who is adopted at one-week of age will have a better chance of "normal" adjustment than a child who is adopted at the age of ten. This may be due in part to the probability that an infant will learn how to trust, where as a ten-year-old may have more difficulty with this task, depending on his history. Eric Erickson, a developmental theorist, discussed trust issues in his theory of development. The first of Erickson's stages of development is Trust v. Mistrust. A child who experiences neglect or abuse can have this stage of development severely damaged. An adopted infant may have the opportunity to fully learn trust, where as an older child may have been shuffled from foster home to group home as an infant, thereby never learning trust. Even though Trust v. Mistrust is a major stage of development, the greatest psychological risk for adopted children occurs during the middle childhood and adolescent years. As children grow and change into adolescents, they begin to search for an identity by finding secure points with which to relate. Unfortunately, adopted children do not have a biological example to which to turn, unless they had an open adoption in which they were able to form a relationship with their biological families as well as their adoptive ones. Also key to the development of trust is the ability to bond with adoptive parents. The absence of a biological bond between the adopted child and the adoptive parents may cause trust issues in the child. Baran stated, "Late adolescence . . . is the period of intensified identity concerns and is a time when the feelings about adoption become more intense and questions about the past increase.