The Attachment theory was developed by Bowlby in order to explain the way children develop in early childhood and how they attachment style influences the way they form relationships throughout the duration of their life (Walker, 2009). Numerous developmentalists state that early associations with our attachment figures give the establishment to later grown-up associations. Bowlby defined this procedure as the continuity hypothesis whereby he claimed that early relationship encounters influence adult relationships in the future to which he viewed attachment as a “lasting psychological connectedness between human beings.” There are many studies to support the theory that early childhood attachments later influences the development of children through to adulthood. Conversely, there are research that disagree with the attachment theory, and therefore, it is essential to investigate whether attachment styles impact the formation of relationships in adolescence and adulthood.The nature of a child’s first attachment is significant in light of the fact that the ‘internal working model’ will powerfully influence the nature of their subsequent relationships (Bowlby, 1969). As per the attachment theory, kids build up an ‘internal working model’ initiating from their first association with their carer. This is then the premise on which they consider what is adequate in future connections and whether they can trust or depend on different people. In addition, children also develop characteristic attachment styles in their initial connections which thereby influences later connections by providing the child with opinions about the people surrounding them, themselves and relationships as a whole. Bowlby (1973) viewed the internal working model as a means to understand the attachment a child has in regards to whether the caregiver’s responses to them are neglectful or caring. The experience the child has during their infancy is transferred to their adolescence and adulthood whereby their thoughts, behaviours and emotional feelings are developed into the formation of future relationships (Bowlby, 1973). As a result of the attachment the child has to their caregiver, the development of depression may also be avoided (Engels, Finkenauer, Meeus, & Dekovic, 2001). Therefore, the relationship between an infant and their primary caregiver directly impacts the relationships an individual has during their adolescence and adulthood.According to Ainsworth, there are many different types of attachments such as secure, insecure-avoidant, insecure-ambivalent and insecure-disorganised. Secure attachment is whereby a child is positive that the attachment figure will be there to fulfil their requirements. The attachment figure is used as a safe base to explore the environment and obtain the attachment figure at times where they are in need (Main, & Cassidy, 1988). In a longitudinal study by Simpson et al., participants were observed based on four key focuses: infancy, early childhood, adolescence and adulthood. Their romantic relationships and attachment type were looked at distinctive stages in order to endeavour to distinguish a relationship between them. The findings upheld the claim that expression of feelings in romantic relationships during adulthood could be traced back to the person’s early attachment experiences. Those who were securely attached as children were more expressive and emotionally attached in romantic relationships during adulthood. Holmes and Johnson (2009) discovered that securely attached individuals have low anxiety and avoidance to which they also expect others to be accepting and responsive. Bartholomew and Horowitz (1991), stated that primary caregivers must always be attentive to their child’s needs as well as providing a secure home for them and showing their child plenty of love and affection in order for their offspring to trust them.Insecure attachment is whereby young children who do not have any relationships with a caregiver who is emotionally invested and available when needed, thus even when there is adequate mental and physical care given they show a range of developmental deficits that they endure over a period of time. Bowlby (1940) displays how sometimes bonding can not prove to be successful between mothers and their children, and how maternal deprivation like that that are found in these cases could seriously affect the child not only at that point but also in their later development in life. According to Bowlby’s belief, the consequences of maternal deprivation could be the cause of: dwarfism, aggressiveness, dependency anxiety (whereby the person is overly clingy), intellectual retardation, lack of affection towards others and depression to name a few. Insecure avoidant children fail to associate to their attachment figure while they are studying their surrounding/environment. Moreover, they are both physically and mentally independent of their attachment figure (Behrens, Hesse & Main, 2007). In the long term they find it difficult to form relationships and to express their feelings. Insecure ambivalent is where children take on an ambivalent behavioural manner towards their attachment figure. Those who are insecure ambivalent usually show highly clingy and dependent behaviour, however they will also be rejecting their attachment figure when they are socialising and interacting with others. The child does not end up developing a sense of security from their attachment figure. However, they also display difficulty in detaching from their attachment figure in order to explore their environment. Finally, these are the personalities who “flees from intimacy, and, like the ambivalent child, tends to be demanding or clingy, immature, and easily overwhelmed by her own emotions (Karen, 1994). The final insecure attachment is the insecure disorganised attachment. Disorganised attachment occurs when the parent either has a number of unworked psychological problems from their own past, thus they have no psychological space left finished for their infant. Children with disorganised attachments frequently demonstrate conflicting, adverse behaviours. They happily welcome the mother when she returns yet they turn away without looking at her, thus making them the most confused and the least secure behavioural example (Papalia et al., 1999).Inability to achieve the objectives in the parent-child relationship will bring about a deficient attachment relationship, putting the youngster on a pathway to relationship difficulties all through life. For instance, the nonattendance of a fundamental feeling of trust may keep a minor from leaving the parental figure’s side to investigate the encompassing condition, in this manner averting opportunities for him to create skill and find out about his/her reality (Gearity, 2005).However, there are implication in regards to the validity and reliability of the attachment theory whereby other researchers have criticised the idea that childhood attachments can influence the way an individual forms relationships during their adolescence and adulthood. For instance, research has shown that parents do not influence their child’s personality or character as peers are believed to have more impact on the way an individual behaves or reacts in comparison to their primary caregiver (Harris, 1998). Another limitation of the attachment theory is the assumption that only mothers can be viewed as the child’s primary caregiver, excluding fathers, siblings and grandparents. Verschueren & Marcoen (1999) discovered that an attachment a child has to their father has many positive attributes as securely attached children have reportedly fewer behavioural issues and are also more sociable. In the strange situation, fathers who had been actively involved in their children’s lives were more likely to have securely attached children (Cox et al., 1992). Fathers who are not actively engaged in their children’s lives are more likely to have children with many behavioural problems, and so, fathers must be present during their offspring’s childhood as it is essential for the infant in order for them to have a secure attachment (Ramchandani et al., 2013). Moreover, a secure attachment is dependent on the nurture of a father’s parenting to which a higher quality of care establishes more securely attached infants (Brown et al., 2007). Thus, researchers must also incorporate the role of a secondary primary caregiver as the involvement of both the father and mother have an impact on the attachment style a child has to their carer.Overall, the evidence presented has suggested that during the duration of childhood, an individual’s attachment style is determined by the attachment to the caregivers as well as present-day relationships. A securely attached adult has the ability to form relationships effortlessly. Although if a secure attachment between a child and caregiver is not formed, there can be negative long-term effects on the child such as depression and anxiety due to the neglect and deprivation the parent has shown to them. Thus an attachment must be formed in order to prevent the development of any negative consequences. Furthermore, there are limitations in the attachment theory that many researchers have pointed out which counters the authenticity of the theory. Therefore, there must be frequently updated research whereby it can determine whether or not attachment is the sole factor that shapes future interpersonal relationships.