understanding interpersonal relationships between human beings. Over the years he formulated his theory of early attachments, Bowlby drew from a range of fields of Attachment theory, originating in the work of John Bowlby, is a psychological, evolutionary and ethological theory that provides a descriptive and explanatory framework for understanding interpersonal relationships between human beings. Over the years he formulated his theory of early attachments, Bowlby drew from a range of fields of thinking and research including forensic psychology (as in his Konrad Lorenz had examined the phenomenon of "imprinting" and felt that it might have some parallels to human attachment. Imprinting, a behavior characteristic of some birds and a very few mammals, involves rapid learning of recognition by a young bird or animal exposed to a conspecific or an object or organism that behaves suitably. The learning is possible only within a limited age period, known as a critical period. This rapid learning and development of familiarity with an animate or inanimate object is accompanied by a tendency to stay close to the object and to follow when it moves; the young creature is said to have been imprinted on the object when this occurs. As the imprinted bird or animal reaches reproductive maturity, its courtship behavior is directed toward objects that resemble the imprinting object. Bowlby's attachment concepts later included the ideas that attachment involves learning from experience during a limited age period, and that the learning that occurs during that time influences adult behavior. However, he did not apply the imprinting concept in its entirety to human attachment, nor assume that human development was as simple as that of birds. He did, however, consider that attachment behavior was best explained as instinctive in nature, an approach that does not rule out the effect of experience, but that stresses the readiness the young child brings to social interactions. Some o Attachment theory, originating in the work of John Bowlby, is a psychological, evolutionary and ethological theory that provides a descriptive and explanatory framework for understanding interpersonal relationships between human beings. Over the years he formulated his theory of early attachments, Bowlby drew from a range of fields of thinking and research including forensic psychology (as in his study of 44 juvenile thieves), ethology, evolutionary biology, object relations theory (the branch of psychoanalysis in which he was trained by Melanie Klein), systems theory and cognitive psychology. In addition to care-seeking by children, peer relationships of all ages, romantic and sexual attraction, and responses to the care needs of infants or sick or elderly adults may be construed as including some components of attachment behavior. == Post-war context == Attachment theory rode a post-World War Two wave in Westernized countries toward child-centred parenting. The child-centred message of Benjamin Spock's post-war manual The Common Sense Book of Baby and Child Care, first published in 1946, put it among the best-selling books of the twentieth century. Konrad Lorenz had examined the phenomenon of "imprinting" and felt that it might have some parallels to human attachment. Imprinting, a behavior characteristic of some birds and a very few mammals, involves rapid learning of recognition by a young bird or animal exposed to a conspecific or an object or organism that behaves suitably. The learning is possible only within a limited age period, known as a critical period. This rapid learning and development of familiarity with an animate or inanimate object is accompanied by a tendency to stay close to the object and to follow when it moves; the young creature is said to have been imprinted on the object when this occurs. As the imprinted bird or animal reaches reproductive maturity, its courtship behavior is directed toward objects that resemble the imprinting object. Bowlby's attachment concepts later included the ideas that attachment involves learning from experience during a limited age period, and that the learning that occurs during that time influences adult behavior. However, he did not apply the imprinting concept in its entirety to human attachment, nor assume that human development was as simple as that of birds. He did, however, consider that attachment behavior was best explained as instinctive in nature, an approach that does not rule out the effect of experience, but that stresses the readiness the young child brings to social interactions. Some of Lorenz's work had been done years before Bowlby formulated his ideas, and indeed some ideas characteristic of ethology were already discussed among psychoanalysts some time before the presentation of attachment theory. Certain types of learning are possible, respective to each applicable type of learning, only within a limited age range known as a critical period. Ethologists expressed concern about the adequacy of some research on which attachment theory was based, particularly the generalization to humans from animal studies. Schur, discussing Bowlby's use of ethological concepts (pre-1960) commented that concepts used in attachment theory had not kept up with changes in ethology itself. Ethologists and others writing in the 1960s and 1970s questioned and expanded the types of behaviour used as indications of attachment. More recently some psychoanalysts have sought to reconcile the two theories in the form of attachment-based psychotherapy, a therapeutic approach. ==== Ethology ==== Ethologists expressed concern about the adequacy of some of the research on which attachment theory was based, particularly the generalisation to humans from animal studies. Schur, discussing Bowlby's use of ethological concepts (pre-1960) commented that these concepts as used in attachment theory had not kept up with changes in ethology itself. Ethologists and others writing in the