Attachment theory

# Overview
An attachment theory is a coherent group of ideas that attempt to explain attachment, the almost universal human tendency to prefer certain familiar companions over other people, especially when ill, injured, or distressed. Historically, certain social preferences, like those of parents for their children, were explained by reference to instinct, or the moral worth of the individual.  Psychological theories about attachment were suggested from the late nineteenth century onward. Current attachment theory originated in the work of John Bowlby and focuses on social experiences in early childhood as the source of attachment in childhood and in later life. Although some of his ideas have been reworked or reinterpreted, the term "attachment theory" is now almost invariably used to refer to the theory developed by Bowlby, and this article will follow that usage.
Attachment theory, as originating in the work of John Bowlby, is a psychological, evolutionary and ethological theory that provides a descriptive and explanatory framework for discussion of interpersonal relationships between human beings. In infants, behavior associated with attachment is primarily a process of proximity seeking to an identified attachment figure in situations of perceived distress or alarm, for the purpose of survival. Infants become attached to adults who are sensitive and responsive in social interactions with the infant, and who remain as consistent caregivers for some months during the period from about six months to two years of age. During the later part of this period, children begin to use attachment figures (familiar people) as a ' 'secure base' 'to explore from and return to. Parental responses lead to the development of patterns of attachment which in turn lead to 'internal working models' which will guide the individual's feelings, thoughts, and expectations in later relationships. The human infant is considered by attachment theorists to have a need for a secure relationship with adult caregivers, without which normal social and emotional development will not occur. However, different relationship experiences can lead to different developmental outcomes. Mary Ainsworth developed a theory of a number of attachment styles in infants in which distinct characteristics were identified known as secure attachment, avoidant attachment, anxious attachment and, later, disorganized attachment.
Other theorists subsequently extended attachment theory to adults. Methods exist for measurement of attachment styles in both older infants and adults, although measurement in middle childhood is problematic. 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.
Bowlby explored a range of fields including evolution by natural selection, object relations theory (psychoanalysis), control systems theory, evolutionary biology and the fields of ethology and cognitive psychology, in order to formulate a comprehensive theory of the nature of early attachments. The main tenets of attachment theory, incorporating thinking from many fields, were presented to the British Psychoanalytic Society in London in three papers: The Nature of the Childs Tie to His Mother (1958), Separation Anxiety (1960a), and Grief and Mourning in Infancy and Early Childhood (1960b). At about the same time, Bowlby's former colleague, Mary Ainsworth was completing extensive observational studies on the nature of infant attachments in Uganda with Bowlby's ethological theories in mind. Mary Ainsworth's innovative methodology and comprehensive observational studies informed much of the theory, expanded its concepts and enabled some of its tenets to be empirically tested. Attachment theory was finally presented in 1969 in Attachment the first volume of the Attachment and Loss trilogy. The second and third volumes, Separation: Anxiety and Anger and Loss: Sadness and Depression followed in 1972 and 1980 respectively. Attachment was revised in 1982 to incorporate more recent research.
Although in the early days Bowlby was criticised by academic psychologists and ostracised by the psychoanalytic community, attachment theory has become the dominant approach to understanding early social development and given rise to a great surge of empirical research into the formation of children's close relationships. There have been significant modifications as a result of empirical research but attachment concepts have become generally accepted. Criticism of attachment theory has been sporadic, some of it relating to an early precursor hypothesis called "maternal deprivation", published in 1951. There has considerable criticism from a variety of disciplines, notably psychoanalysis, and from ethologists in the 1970s. More recent criticism relates to the complexity of social relationships within family settings , and the limitations of discrete styles for classifications  A number of treatment approaches, some currently in the process of being evaluated, are based on applications of attachment theory.

# "Attachment" in attachment theory
An attachment, as defined in attachment theory, has the specific meaning of a bond or tie felt by an individual toward an attachment figure. Between two adults, such bonds would be expected to be often reciprocal and mutual; however, as felt by children toward parental or other adult carers, any such bonds would likely involve asymmetries. Attachment theory proposes that needs for safety, security and protection underlie attachment, hence, as this need is paramount in infancy and childhood, the theory predicts that child-to-adult bonds will be more salient to behaviour and mood than others, as well as asymmetric. Attachment theory posits that children attach to carers instinctively,
for the purpose of security, survival and, ultimately, genetic replication.
Attachment theory is not intended as an exhaustive description of relationships  neither between adults nor between child and caregiver. Attachment is not synonymous with love and affection either. Although love and affection may indicate bonds exist, the bonds proposed by attachment theory, strictly speaking, presuppose needs rather than affection. In the case of child-to-adult relationships, the child's tie is the "attachment" and the caregiver's reciprocal equivalent is referred to as the "caregiving bond".
Attachment operates through the attachment behavioural system. There are many diverse behaviours within it which may also serve other behavioural systems but they serve a common outcome; either to maintain proximity or achieve closer proximity to the attachment figure. Attachment has also been described as an attitude, or readiness for certain behaviours, that one person displays toward another. The attachment attitude involves the seeking of proximity to the other person and may include a variety of other attachment behaviours, but attachment behaviours are likely to occur only in threatening or uncomfortable circumstances.
Thus, attachment may be present without necessarily being displayed behaviourally, and it may be impossible to measure the presence of this attitude without creating some apparently threatening circumstance such as the approach of an unfamiliar person.  Infant exploration is greater when the caregiver is present and diminished in their absence. With the attachment figure present the infant's attachment system is relaxed and it is free to explore. If the caregiver is inaccessible or unresponsive, attachment behaviour is strongly activated. During the period of 6 months to two years period the child's behaviour towards the caregiver becomes organised on a goal-directed basis to achieve the conditions that make him feel secure. With the development of locomotion the infant begins to use his carer(s) as a safe base from which to explore. In adolescents, the role of the caregiver is to be available when needed whilst the adolescent makes sorties into the outside world.
In Attachment (1969) Bowlby asserts that, almost from the first, many children have more than one figure towards whom they direct attachment behaviour, but that these figures are not treated alike. Infants show clear discrimination, particularly when tired or ill, and attachment figures can be arranged in hierarchical order with the "principal attachment figure" at the top. Bowlby called the activation of the attachment behavioural system caused by fear of danger, "alarm". However, the fear of being cut off from one's base, the attachment figure (caregiver), he termed "anxiety". If the figure is unavailable or unresponsive, separation distress occurs and the anticipation of such an occurence arouses separation anxiety.
Attachment theory accepts the customary primacy of the mother as the main care-giver and therefore the person who interacts most with a young child, but there is nothing in the theory to suggest that fathers are not equally likely to become principal attachment figures if they happen to provide most of the childcare and related social interaction. Infants will form attachments to any consistent caregiver who is sensitive and responsive in social interactions with the infant. The quality of the social engagement appears to be more influential than amount of time spent. Although it is usual for the principal attachment figure to be the biological mother, the role can be taken by adoptive or foster mothers and others who behave in a "mothering" way, by which is meant to engage in lively social interaction with the infant and to respond readily to signals and approaches.

## Tenets of attachment theory
Attachment theory uses a set of assumptions to connect observable human social behaviours. These assumptions form a coherent whole that fits with available data. The following is a list of the assumptions that form the theory:
- Adaptiveness: Common human attachment behaviours and emotions are adaptive. Evolution of human beings has involved selection for social behaviours that make individual or group survival more likely. For example, the commonly observed attachment behaviour of toddlers includes staying near familiar people; this behaviour would have had safety advantages in the environment of early adaptation, and still has such advantages today. Bowlby termed proximity-seeking to the attachment figure in the face of threat to be the "set-goal" of the attachment behavioural system. There is a survival advantage in the capacity to sense possibly dangerous conditions such as unfamiliarity, being alone or rapid approach, and such conditions are likely to activate the attachment behavioural system causing the infant or child to seek proximity to the attachment figure.
- Critical period: Certain changes in attachment, such as the infant's coming to prefer a familiar caregiver and avoid strangers, are most likely to occur within the period between about six months of age and two or three years. It became apparent there were more differences than similarities with imprinting and the analogy was dropped. Bowlby's sensitivity period has been modified to a less "all or nothing" approach so that although there is seen to be a sensitive period during which it is highly desirable that selective attachments develop, the time frame is probably broader and the effects not so fixed and irreversible. With further research it has come to be appreciated that social development is affected by later as well as earlier relationships.
- Robustness of development: Attachment to and preferences for some familiar people are easily developed by most young humans, even under far less than ideal circumstances.
- Experience as essential factor in attachment: Infants in their first months have no preference for their biological parents over strangers and are equally friendly to anyone who treats them kindly. Preferences for particular people, and behaviours which solicit their attention and care, develop over a period of time.
- Monotropy: Early steps in attachment take place most easily if the infant has one caregiver, or the occasional care of a small number of other people. According to Bowlby, almost from the first many children have more than one figure towards whom they direct attachment behaviour; these figures are not treated alike and there is a strong bias for attachment behaviour to become directed mainly towards one particular person. This bias to attach especially to one figure Bowlby called "monotropy". This concept has been effectively abandoned insofar as it may be taken to mean that the relationship with the special figure differs qualitatively from that of other figures. Rather there are seen to be definite hierarchies. According to Mary Main (1999), "although there is general agreement that an infant or adult will have only a few attachment figures at most, many attachment theorists and researchers believe that infants form "attachment hierarchies" in which some figures are primary, others secondary and so on. This position can be presented in a stronger form, in which a particular figure is believed continually to take top place ("monotropy")......questions surrounding monotropy and attachment hierarchies remain unsettled."
- Social interactions as cause of attachment: Feeding and relief of an infant's pain do not cause an infant to become attached to a caregiver. Infants become attached to adults who are sensitive and  responsive in social interactions with the infant, and who remain as consistent caregivers for some time.
- Internal working model: Early experiences with caregivers gradually give rise to a system of thoughts, memories, beliefs, expectations, emotions, and behaviours about the self and others. This system, called the internal working model of social relationships, continues to develop with time and experience, enables the child to handle new types of social interactions. For example, a child's internal working model helps him or her to know that an infant should be treated differently from an older child, or to understand that interactions with a teacher can share some of the characteristics of an interaction with a parent. An adult's internal working model continues to develop and to help cope with friendships, marriage, and parenthood, all of which involve different behaviours and feelings. The internal working model is likely to owe much to the individual's early experiences with caregivers, but it can and does change with both real and vicarious experiences.
- Transactional processes: As attachment behaviours change with age, they do so in ways shaped by relationships, not by individual experiences. A child's behaviour when reunited with a caregiver after a separation is determined not only by how the caregiver has treated the child before, but on the history of effects the child has had on the caregiver in the past.
- Consequences of disruption: In spite of the robustness of attachment, significant separation from a familiar caregiver, or frequent changes of caregiver that prevent development of attachment, may result in psychopathology at some point in later life.
- Developmental changes: Specific attachment behaviours begin with predictable, apparently innate, behaviour in infancy, but change with age in ways that are partly determined by experiences and by situational factors. For example, a toddler is likely to cry when separated from his mother, but an eight-year-old is more likely to call out, "When are you coming back to pick me up?" and/or to turn away and begin the familiar school day. 

# Attachment styles
Mary Ainsworth's innovative methodology and comprehensive observational studies, particularly those undertaken in Scotland and the Ganda, informed much of the theory, expanded its concepts and enabled its tenets to be empirically tested. Some authors see attachment theory as effectively the joint work of Ainsworth and Bowlby. Mary Ainsworth conducted research based on Bowlby's early formulation of the theory and identified different attachment styles which are not, strictly speaking, part of attachment theory but are very closely identified with it. She devised a protocol known as the Strange Situation Procedure, still used today to assess attachment styles in children, as the laboratory portion of a larger study that included extensive home visitations over the first year of the child's life.  Her studies identified three attachment patterns that a child may have with his primary attachment figure: secure, anxious-avoidant (insecure) and anxious-ambivalent (insecure).
Further research by Dr. Mary Main and colleagues (University of California at Berkeley) identified a fourth attachment pattern, called disorganized/disoriented attachment, which reflects these children's lack of a coherent coping strategy.  For research purposes, anxious-avoidant is called A, secure is called B, anxiousambivalent (or "resistant") is called C and disorganized/disoriented is called D.

### Description of styles
- Secure Attachment - The child protests the mother's departure and quiets promptly on the mother's return, accepting comfort from her and returning to exploration.
- Avoidant Attachment - The child shows little to no signs of distress at the mother's departure, a willingness to explore the toys, and little to no visible response to the mother's return.
- Ambivalent Attachment - The child shows sadness on the mother's departure, ability to be picked up by the stranger and even 'warm' to the stranger, and on the mother's return, some ambivalence, signs of anger, reluctance to 'warm' to her and return to play.
- Disorganized Attachment - The child presents stereotypes upon the mother's return after separation, such as freezing for several seconds or rocking. This appears to indicate the child's lack of coherent coping strategy. Children who are classified as disorganized are also given a classification as secure, ambivalent or avoidant based on their overall reunion behaviour.
Additionally, the attachment patterns observed in children are correlated with certain behavior patterns and communication styles in the attachment figure:
- Secure Attachment - The attachment figure responds appropriately, promptly and consistently to the emotional as well as the physical needs of the child.  She helps her child to transition and regulate stress, and as a result, the child uses her as a secure base in the home environment.
- Avoidant Attachment - The attachment figure shows little response to the child when distressed.  She discourages her child from crying and encourages independence and exploration.  The avoidantly attached child may have lower quality play than the securely attached child.
- Ambivalent Attachment - The attachment figure is inconsistent with her child; she may at some times be appropriate and at other times neglectful to the child.  The child raised in an ambivalent relationship becomes preoccupied with the mother's availability and cannot explore his environment freely or use his mother as a secure base.  The ambivalently attached child is vulnerable to difficulty coping with life stresses and may display role reversal with the mother.
- Disorganized Attachment - This can be associated with frightened/disoriented behaviour, intrusiveness/negativity and withdrawal, role/boundary confusion, affective communication errors and child maltreatment.
Other methods have been developed for the assessment of styles in children beyond the age of 18 months. Research from the Minnesota longitudinal study assessed children at 12 and 18 months, four years, middle childhood, 13 years and 15 years and followed children into the school environment. Securely attached children were the least isolated and most popular, the most likely to respond empathically and the least likely to bully or be bullied. Bullies were most likely to be classified as anxiousavoidant and victims as anxiousambivalent.
More recent research sought to ascertain the extent to which a parents attachment classification is predictive of their childrens classification and found that parents perceptions of their own childhood attachments predicted their childrens attachment classifications 75% of the time.

# Changes in attachment after the infant-toddler period
According to Bowlby's theory, the child's early experience of social interactions with familiar people leads to the development of an internal working model of social relationships, a set of ideas and feelings that establish the individual's expectations about relationships, the behaviour of others toward him or her, and the behaviours appropriate for him or her to show to others. The internal working model continues to develop and become more complex with age, cognitive growth, and continued social experience. As the internal working model of relationships advances, attachment-related behaviours lose some of the characteristics so typical of the infant-toddler period, and take on a series of age-related tendencies. 
Some authors have suggested continuous rather than categorical gradations between attachment patterns, and have discussed dimensions of underlying security rather than the classifications derived from Ainsworth's work 
In considering the development of attachment behavior and the internal working model after the toddler period it has been posited that the preschool period involves the use of negotiation, bargaining, and compromise as part of attachment behaviour, and that these social skills ideally become incorporated into the internal working model of social relationships, to be used with other children and later with adult peers. As children move into the school years, most develop a goal-corrected partnership with parents, in which each partner is willing to give up some desires in order to maintain the relationship in a gratifying form. Incorporation of this type of partnership into the internal working model prepares the growing child for later mature friendships, marriage, and parenthood. The mature internal working model of social relationships thus advances far beyond the basic desire to maintain proximity to familiar people, although this type of behaviour may continue to be present in times of threat or pain.
Relationships with peers have an influence distinct to that of parents but parent-child relationships can be influence the peer relationships children form. For example, secure attachment status is said to promote social competance and positive peer relationships. Relationships formed with peers are influential in the acquisition of social skills, to intellectual development and to the formation of social identity. Classification of childrens peer status, (popular, neglected or rejected) has been found to predict subsequent adjustment although, as with attachment to parental figures, subsequent experiences may well alter the course of development.

# Attachment in adults
Attachment theory was extended to adult romantic relationships in the late 1980s by Cindy Hazan and Phillip Shaver. Four styles of attachment have been identified in adults: secure, anxious-preoccupied, dismissive-avoidant, and fearful-avoidant. Investigators have explored the organization and the stability of mental working models that underlie these attachment styles. They have also explored how attachment impacts relationship outcomes and how attachment functions in relationship dynamics. Generally attachment style is used by social psychologists interested in romantic attachment, and attachment status by developmental psychologists interested in the individual's state of mind with respect to attachment. The latter is more stable, while the former fluctuates more.
Some authors have suggested that adults' internal working models do not involve a single perspective, but instead entail a hierarchy of models containing general ideas about close relationships, and within those, information related to specific relationships or even specific events within a relationship. One interesting idea about the hierarchy of models is that information at different levels need not be consistent. 
Attachment in adults is commonly measured using the Adult Attachment Interview and self-report questionnaires. Self-report questionnaires have identified two dimensions of attachment, one dealing with anxiety about the relationship, and the other dealing with avoidance in the relationship. There are a wide variety of attachment measures used in adult attachment research. The most popular measure in the social psychological research is the Experiences in Close Relationships-Revised scale.

# History

## Earlier theories of attachment
Attachment theory was developed by Bowlby as a consequence of his dissatisfaction with existing theories of early relationships. The concept of infants' emotional attachment to caregivers has been known anecdotally for hundreds of years. Most early observers focused on the anxiety displayed by infants and toddlers when threatened with separation from a familiar caregiver  Freudian theory attempted a systematic consideration of infant attachment and attributed the infant's attempts to stay near the familiar person to motivation learned through feeding experiences and gratification of libidinal drives.
In the 1930s, the British developmentalist Ian Suttie put forward the suggestion that the child's need for affection was a primary one, not based on hunger or other physical gratifications. A third theory prevalent at the time of Bowlby's development of attachment theory was "dependency". This approach posited that infants were dependent on adult caregivers but that dependency was, or should be outgrown as the individual matured. Such an approach perceived attachment behaviour in older children as regressive whereas within attachment theory older children and adults remain attached and indeed a secure attachment is associated with independent exploratory behaviour rather than dependence. William Blatz, a Canadian psychologist and teacher of Bowlby's colleague Mary Ainsworth, was among the first to stress the need for security as a normal part of personality at all ages, as well as normality of the use of others as a secure base and the importance of social relationships for other aspects of development. 

## Early developments
Bowlby was influenced by the beginnings of the object relations school of psychoanalysis and in particular, Melanie Klein, although he profoundly disagreed with the psychoanalytic belief then prevalent that saw infants responses as relating to their internal fantasy life rather than to real life events. As Bowlby began to formulate his concept of attachment, he was influenced by case studies such as one by David Levy. that associated an adopted child's lack of social emotion to her early emotional deprivation. Bowlby himself was interested in the role played in delinquency by poor early relationships, and explored this in a study of young thieves. Bowlby's contemporary Rene Spitz proposed that "psychotoxic" results were brought about by inappropriate experiences of early care. A strong influence was the work of James Robertson who filmed the effects of separation on children in hospital. He and Bowlby collaborated in making the 1952 documentary film A Two-Year Old Goes to the Hospital illustrating the impact of loss and suffering experienced by young children separated from their primary caretakers. This film was instrumental in a campaign to alter hospital restrictions on visiting by parents.
In his 1951 monograph for the World Health Organization, Maternal Care and Mental Health, Bowlby propounded the hypothesis that "the infant and young child should experience a warm, intimate, and continuous relationship with his mother (or permanent mother substitute) in which both find satisfaction and enjoyment" and that not to do so may have significant and irreversible mental health consequences. This proposition was both influential in terms of the effect on the institutional care of children, and highly controversial. There was limited empirical data at the time and no comprehensive theory to account for such a conclusion.

## Attachment theory
Following the publication of Maternal Care and Mental Health Bowlby sought new understanding from such fields as evolutionary biology, ethology, developmental psychology, cognitive science and control systems theory and drew upon them to formulate the innovative proposition that the mechanisms underlying an infants tie emerged as a result of evolutionary pressure. He realised that he had to develop a new theory of motivation and behaviour control, built on up-to-date science rather than the outdated psychic energy model espoused by Freud. Bowlby expressed himself as having made good the "deficiencies of the data and the lack of theory to link alleged cause and effect" in "Maternal Care and Mental Health" in his later work "Attachment and Loss" published between 1969 and 1980.
The formal origin of attachment theory can be traced to the publication of two 1958 papers, one being Bowlby's The Nature of the Child's Tie to his Mother, in which the precursory concepts of "attachment" were introduced, and Harry Harlow's The Nature of Love, based on the results of experiments which showed, approximately, that infant rhesus monkeys spent more time with soft mother-like dummies that offered no food than they did with dummies that provided a food source but were less pleasant to the touch. Bowlby followed this up with two more papers, Separation Anxiety (1960a), and Grief and Mourning in Infancy and Early Childhood (1960b). Bowlby's three early papers broadly introduce the concepts subsequently set out fully in his three volumes of Attachment and Loss.

### Ethology
Bowlby's attention was first drawn to ethology when he read Lorenz's 1952 publication in draft form although Lorenz had published much earlier work. Soon after this he encountered the work of Tinbergen, and began to collaborate with Robert Hinde. In 1953 he stated "the time is ripe for a unification of psychoanalytic concepts with those of ethology, and to pursue the rich vein of research which this union suggests".
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 a 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.

### Psychoanalysis
Bowlby's view of attachment was also influenced by psychoanalytical concepts and the earlier work of psychoanalysts. In particular he was influenced by observations of young children separated from familiar caregivers, as provided during World War II by Anna Freud and her colleague Dorothy Burlingham. Observations of separated children's grief by Rene Spitz were another important factor in the development of attachment theory. However, Bowlby rejected psychoanalytical explanations for early infant bonds. He rejected both Freudian "drive-theory", which he called the "cupboard-love" theory of relationships, and early object-relations theory as both in his view failed to see the attachment as a psychological bond in its own right rather than an instinct derived from feeding or sexuality. Thinking in terms of primary attachment and neo-darwinism, Bowlby identified as what he saw as fundamental flaws in psychoanalysis, namely the overemphasis of internal dangers at the expense of external threat, and the picture of the development of personaltiy via linear "phases" with "regression" to fixed points accounting for psychological illness. Instead he posited that several lines of development were possible, the outcome of which depended on the interaction between the organism and the environment. In attachment this would mean that although a developing child has a propensity to form attachments, the nature of those attachments depends on the environment to which the child is exposed.

### Internal working model
The important concept of the internal working model of social relationships was adopted by Bowlby from the work of Kenneth Craik, the philosopher . Craik had noted the adaptiveness of the ability of thought to predict events, and stressed the survival value of and natural selection for this ability. According to Craik, prediction occurs when a "small-scale model" consisting of brain events is used to represent not only the external environment, but the individual's own possible actions. This model allows a person to mentally try out alternatives and to use knowledge of the past in responding to the present and future. At about the same time that Bowlby was applying Craik's ideas to the study of attachment, other psychologists were using these concepts in discussion of adult perception and cognition 

### Cybernetics
The theory of control systems (cybernetics), developing during the 1930s and '40s, influenced Bowlby's thinking.. The young child's need for proximity to the attachment figure was seen as balancing homeostatically with the need for exploration. The actual distance maintained would be greater or less as the balance of needs changed; for example, the approach of a stranger, or an injury, would cause the child to seek proximity when a moment before he had been exploring at a distance.

## Behavioural development and attachment
Behaviour analysts have constructed models of attachment. Such models are based on the importance of contingent relationships. Behaviour analytic models have received support from research  and meta-analytic reviews

## Developments
Although research on attachment behaviors continued after Bowlby's death in 1990, there was a period of time when attachment theory was considered to have run its course. Some authors argued that attachment should not be seen as a trait (lasting characteristic of the individual), but instead should be regarded as an organizing principle with varying behaviors resulting from contextual factors. Related later research looked at cross-cultural differences in attachment, and concluded that there should be re-evaluation of the assumption  that attachment is expressed identically in all humans  In a recent study conducted in Sapporo, Behrens, et al., 2007 found attachment distributions consistent with global norms using the six-year Main & Cassidy scoring system for attachment classification.
Interest in attachment theory continued, and the theory was later extended to adult romantic relationships by Cindy Hazen and Phillip Shaver.
 Peter Fonagy and Mary Target have attempted to bring attachment theory and psychoanalysis into a closer relationship by way of such aspects of cognitive science as mentalization, the ability to estimate what the beliefs or intentions of another person may be.  A "natural experiment" has permitted extensive study of attachment issues, as researchers have followed the thousands of Romanian orphans who were adopted into Western families after the end of the Ceasescu regime. The English and Romanian Adoptees Study Team, led by Michael Rutter, has followed some of the children into their teens, attempting to unravel the effects of poor attachment, adoption and new relationships, and the physical and medical problems associated with their early lives. Studies on the Romanian adoptees, whose initial conditions were shocking, have in fact yielded reason for optimism. Many of the children have developed quite well, and the researchers have noted that separation from familiar people is only one of many factors that help to determine the quality of development. 

## Effects of changing times and approaches
Some authors have noted the connection of attachment theory with Western family and child care patterns characteristic of Bowlby's time. The implication of this connection is that attachment-related experiences (and perhaps attachment itself) may alter as young children's experience of care change historically. For example, changes in attitudes toward female sexuality have greatly increased the numbers of children living with their never-married mothers and being cared for outside the home while the mothers work. This social change, in addition to increasing abortion rates, has also made it more difficult for childless people to adopt infants in their own countries, and has increased the number of older-child adoptions and adoptions from third-world sources.
Adoptions and births to same-sex couples have increased in number and even gained some legal protection, compared to their status in Bowlby's time.
One focus of attachment research has been on the difficulties of children whose attachment history was poor, including those with extensive non-parental child care experiences. Concern with the effects of child care was intense during the so-called "day care wars" of the late 20th century, during which the deleterious effects of day care were stressed.  As a beneficial result of this controversy, training of child care professionals has come to stress attachment issues and the need for relationship-building through techniques such as assignment of a child to a specific care provider. Although only high-quality child care settings are likely to follow through on these considerations, nevertheless a larger number of infants in child care receive attachment-friendly care than was the case in the past, and emotional development of children in nonparental care may be different today than it was in the 1980s or in Bowlby's time.
Finally, any critique of attachment theory needs to consider how the theory has connected with changes in other psychological theories. Research on attachment issues has begun to include concepts related to behaviour genetics and to the study of temperament (constitutional factors in personality), but it is unusual for popular presentations of attachment theory to include these. Importantly, some researchers and theorists have begun to connect attachment with the study of mentalization or Theory of Mind, the capacity that allows human beings to guess with some accuracy what thoughts, emotions, and intentions lie behind behaviours as subtle as facial expression or eye movement. The connection of theory of mind with the internal working model of social relationships may open a new area of study and lead to alterations in attachment theory. 

# Criticism and controversy
Criticism of Bowlby's view of attachment has been sporadic, but began even before the theory was completely formulated.

### Early criticism
Bowlby's colleague M.D.S. Ainsworth listed nine concerns that she felt were chief points of controversy related to the attachment theory precursor referred to as "maternal deprivation", a system that includes some of the tenets that later made up attachment theory. 1) The vagueness of the term "maternal deprivation" used in the description of a child's history of attachment experiences. 2) The lack of clarity of the theory's implications for experiences with multiple caregivers. 3) The implications for the theory of the degree of variability following "deprivation." 4) The question of what specific effects result from "deprivation". 5) The question of individual differences in children's reactions to separation or loss. 6) The question of the degree of permanence of specific effects of "deprivation". 7) The question of delinquency as an infrequent outcome of separation and loss. 8) The question of specifics of deprivation and whether these have to do with the caregiver or the more general environment. 9) Controversies having to do with the effects of genetic defects or of brain damage on the developmental outcome..
As the formulation of attachment theory progressed, critics commented on empirical support for the theory and for the possible alternative explanations for results of empirical research. One critic questioned the suggestion that early attachment history (as it would now be called) had a lifelong impact. Another critic discussed how mother and child could provide each other with positive reinforcement experiences through their mutual attention and therefore learn to stay close together; this explanation would make it unnecessary to posit innate human characteristics fostering attachment.

### Later criticisms
Some past criticism stressed the gradual disappearance of some of the theory's constructs from frequent use. In the 1970s, problems with the emphasis on attachment as a trait (a stable characteristic of an individual) rather than as a type of behaviour with important organizing functions and outcomes, led to a situation where some authors considered that "attachment (as implying anything but infant-adult interaction)  outlived its usefulness as a developmental construct..." and that attachment behaviours were best understood in terms of their functions in the child's life.
A given function, such as as achieving a sense of security, might be achieved in different ways by children of different ages and in different environments, and the different but functionally comparable behaviours should be categorized as related to each other. This way of thinking later developed into a discussion of the secure base concept as a central aspect of attachment theory, but one which had all too often been omitted from consideration. Commenting on secure base behaviour, the organization of exploration of an unfamiliar situation around returns to a familiar person, it has been noted that the "secure base construct is central to the logic and coherence of attachment theory and to its status as an organizational construct." Similarly, it has been pointed out that "other features of early parent-child relationships that develop concurrently with attachment security, including negotiating conflict and establishing cooperation, also must be considered in understanding the legacy of early attachments." 

## Criticism from specific disciplines
It may be useful to discuss criticism of attachment theory from the viewpoint of the five lines of thought that influenced its formulation: psychoanalysis. evolution, ethology, control systems, and cognition.  The clinical and observational evidence on which the theory was based has also been criticized.

### Psychoanalysis
From an early point in the development of attachment theory, there was criticism of the theory's lack of congruence with the various branches of psychoanalysis. Like other members of the British object-relations group, Bowlby rejected Melanie Klein's views that considered the infant to have certain mental capacities at birth and to continue to develop emotionally on the basis of fantasy rather than of real experiences. But Bowlby also withdrew from the object-relations approach (exemplified, for example, by Anna Freud), as he abandoned the "drive theory" assumptions in favor of a set of automatic, instinctual behaviour systems that included attachment. Bowlby's decisions left him open to criticism from well-established thinkers working on problems similar to those he addressed.   Bowlby was effectively ostracized from the psychoanalytic community although more recently some psychoanalysts have sought to reconcile the two theories in the form of a therapeutic approach.

### Ethology
Ethologists expressed concern about the adequacy of some of the research on which attachment theory was based, particularly the use of generalization to humans from animal studies, an important point in ethological work, where comparison of species was frequently done. Not all animals are suitable for generalization to human beings.  The use of data from animals in the formulation of attachment theory drew serious criticisms such as the following: "...it must be emphasized that data derived from species other than man can be used only to suggest (italics) hypotheses that may be worth applying to man for testing by critical observations. In the absence of critical evidence derived from observing man such hypotheses are no more than intelligent guesses. There is a danger in human ethology... that interesting, but untested, hypotheses may gain the status of accepted theory.  has coined the term 'ethologism' as a label for the present vogue ... for uncritically invoking the findings from ethological studies of other species as necessary and sufficient explanations... Theory based on superficial analogies between species has always impeded biological understanding... We conclude that a valid ethology of man must be based primarily on data derived from man, and not on data obtained from fish, birds, or other primates."
Ethologists like Robert Hinde also expressed concern with some of the language commonly used in discussion of attachment issues. He noted that it was important to use the word "attachment" as a data term, not to imply that it was an intervening variable or a hypothesized internal mechanism. He suggested that confusion about the meaning of attachment theory terms "could lead to the 'instinct fallacy' of postulating a mechanism isopmorphous with the behaviours, and then using that as an explanation for the behaviour". However, Hinde considered "attachment behaviour system" to be an appropriate term of theory language which did not offer the same problems "because it refers to postulated control systems that determine the relations between different kinds of behaviour."
Ethologists and others writing in the 1960s and 1970s questioned the types of behaviour used as indications of attachment, and offered alternative approaches. For example, crying on separation from a familiar person was suggested as an index of attachment. Observational studies of young children in natural settings also provided behaviours that might be considered to indicate attachment; for example, in one study of toddlers in parks with their mothers, the children were observed to stay within a predcitable distance of the mother without effort on her part. The children walked when moving away from the mother, but ran when returning to her. When the child saw or heard something surprising, he or she related this to the mother, looking at her while pointing to the event if at a distance, pointing and tapping her with the other hand if near. The toddlers, unexpectedly, did not follow the mother if she moved away, but most "froze" in place. Another unanticipated indication of the relationship was that the toddler picked up small objects and brought them to the mother, a behaviour that did not usually occur in behaviour toward other adults who were present. Although ethological work tended to be in agreement with Bowlby, work like that just described led to the conclusion that "e appear to disagree with Bowlby and Ainsworth on some of the details of the child's interactions with its mother and other people". Some ethologists pressed for further observational data, arguing that psychologists "are still writing as if there is a real entity which is 'attachment', existing over and above the observable measures." 
One discussant of 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. For example, this author said, Bowlby "assumes the fully innate, unlearned character of most complex behavior patterns" whereas recent animal studies showed "both the early impact of learning and the great intricacy of the interaction between mother and litter". Again, this author criticizes Bowlby for applying "to human behavior an instinct concept which neglects the factor of development and learning far beyond even the position taken by Lorenz  in his early propositions." 
None of the criticisms or suggestions of ethologists appear to have influenced the current use of attachment theory or the designs of related research. Ethological concepts are currently used in related work on robotic systems 

### Cognitive development
Criticism from the viewpoint of cognition has been much less frequent. However, Bowlby's reliance on Piaget's theory of cognitive development gave rise to questions about object permanence (the ability to remember an object that is temporarily absent) and its connection to early attachment behaviours, and about the fact that the infant's ability to discriminate strangers and react to the mother's absence seems to occur some months earlier than Piaget suggested would be cognitively possible. More recently, it has been noted that the understanding of mental representation has advanced so much since Bowlby's day that present views can be far more specific than those of Bowlby's time.

## Criticism of methodology
In addition to criticism of the basic concepts and methods of attachment theory, there has been criticism of research techniques and conclusions drawn from data. For example,the idea of attachment styles, thought to be measured by techniques like the Strange Situation, has been questioned. Such techniques yield a taxonomy of categories considered to represent qualitative difference in attachment relationships (for example, secure attachment versus avoidant). However, a categorical model is not necessarily the best representation of individual difference in attachment. An examination of data from 1139 15-month-olds showed that variation was continuous rather than falling into natural groupings. This criticism introduces important questions for attachment typologies and the mechanisms behind apparent types, but in fact has relatively little relevance for attachment theory itself, which "neither requires nor predicts discrete patterns of attachment." As was noted above, ethologists have suggested other behavioural measures that may be of greater importance than Starnge Situation behaviour.
There has been critical discussion of conclusions drawn from clinical and observational work, and whether or not they actually support tenets of attachment theory. For example, at least one author based criticism of a basic tenet of attachment theory on the work of Anna Freud with children from Theresienstadt, who apparently developed relatively normally in spite of serious deprivation during their early years. This discussion concluded from Freud's case and from some other studies of extreme deprivation that there is an excellent prognosis for children with this background, unless there are biological or genetic risk factors.  The psychoanalyst Margaret Mahler interpreted ambivalent or aggressive behavior of toddlers toward their mothers as a normal part of development, not as evidence of poor attachment history.  Bowlby's interpretations of the data reported by James Robertson were eventually rejected by the researcher, who reported data from 13 young children who were cared for in ideal circumstances during separation from their mothers. Robertson noted," ...Bowlby acknowledges that he draws mainly upon James Robertson's institutional data. But in developing his grief and mourning theory, Bowlby, without adducing noninstitutional data, has generalized Robertson's concept of protest, despair and denial beyond the context from which it was derived. He asserts that these are the usual responses of young children to separation from the mother regardless of circumstance..."; however, of the 13 separated children who received good care, none showed protest and despair, but "coped with separation from the mother when cared for in conditions from which the adverse factors which complicate institutional studies were absent". 

## Recent criticism
Recent critics such as J. R. Harris, Stephen Pinker and Jeremy Kagan,are generally concerned with the concept of infant determinism and stress the possible effects of later experience on personality. Harris and Pinker have put forward the notion that the influence of parents has been much exaggerated and that socialization takes place primarily in peer groups, although H.Rudolph Schaffer concludes that parents and peers fulfil different functions and have distinctive roles in childrens development.
Another recent concern about attachment theory has to do with the fact that infants often have multiple relationships, within the family as well as in child care settings, and that the dyadic model characteristic of attachment theory cannot address the complexity of real-life social experiences.

# Attachment theory in clinical practice

## Clinical practice
Mainstream prevention programs and treatment approaches for attachment difficulties or disorders for infants and younger children are based on attachment theory and concentrate on increasing the responsiveness and sensitivity of the caregiver, or if that is not possible, placing the child with a different caregiver. These approaches are mostly in the process of being evaluated. The programs invariably include a detailed assessment of the attachment status or caregiving responses of the adult caregiver as attachment is a two-way process involving attachment behavior and caregiver response. Some of these treatment or prevention programs are specifically aimed at foster carers rather than parents, as the attachment behaviors of infants or children with attachment difficulties often do not elicit appropriate caregiver responses. Approaches include "Watch, wait and wonder", manipulation of sensitive responsiveness, modified "Interaction Guidance", "Preschool Parent Psychotherapy", "Circle of Security", "Attachment and Biobehavioral Catch-up" (ABC), the New Orleans Intervention, and Parent-Child psychotherapy. Other treatment methods include Developmental, Individual-difference, and Relationship-based therapy (DIR, also referred to as Floor Time) by Stanley Greenspan, although DIR is primarily directed to treatment of pervasive developmental disorders.
The relevance of these approaches to intervention with fostered and adopted children with reactive attachment disorder or older children with significant histories of maltreatment is unclear.
Outside the mainstream programs is a form of treatment generally known as attachment therapy, a subset of techniques (and accompanying diagnosis) for supposed attachment disorders including RAD. In general, these therapies are aimed at adopted or fostered children with a view to creating attachment in these children to their new caregivers. The theoretical base is broadly a combination of regression and catharsis, accompanied by parenting methods which emphasize obedience and parental control. There is considerable criticism of this form of treatment and diagnosis as it is largely unvalidated and has developed outside the scientific mainstream. There is little or no evidence base and techniques vary from non-coercive therapeutic work to more extreme forms of physical, confrontational and coercive techniques, of which the best known are holding therapy, rebirthing, rage-reduction and the Evergreen model. These forms of the therapy may well involve physical restraint, the deliberate provocation of rage and anger in the child by physical and verbal means including deep tissue massage, aversive tickling, enforced eye contact and verbal confrontation, and being pushed to revisit earlier trauma. Critics maintain that these therapies are not within the attachment paradigm, are potentially abusive, and are antithetical to attachment theory. The APSAC Taskforce Report of 2006 notes that many of these therapies concentrate on changing the child rather than the caregiver. Children may be described as "RADs", "Radkids" or "Radishes" and dire predictions may be made as to their supposedly violent futures if they are not treated with attachment therapy.

## Reactive attachment disorder
Reactive attachment disorder  sometimes referred to by its initials, "RAD"  is a psychiatric diagnosis (DSM-IV-TR 313.89, ICD-10 F94.1/2). The essential feature of reactive attachment disorder is markedly disturbed and developmentally inappropriate social relatedness in most contexts that begins before age five years and is associated with gross pathological care.  There are two subtypes, one reflecting the disinhibited attachment pattern and the other reflecting the inhibited pattern. RAD denotes a lack of age appropriate attachment behaviours that amount to a clinical disorder rather than a description of insecure of disorganised  attachment styles however problematic those styles may be. Despite its popularisation on the Web within the field of an unvalidated alternative therapy known as attachment therapy for a range of perceived behavioural difficulties in children, it is thought to be rare.

## Attachment disorder
Attachment disorder is an ambiguous term. It may be used to refer to reactive attachment disorder, the only 'official' clinical diagnosis, or the more problematical attachment styles, or within the alternative medicine field of attachment therapy as a form of unvalidated diagnosis.