Studies of have shown how important mothers are in the development of their children. For an infant, development is facilitated when bounding between mother and baby occurs. At one time it was believed that food provided by mothers was what caused infants to bound with their mothers. Studies proved that wrong and showed there is more to how and why infants bound to their mothers.

To challenge this idea a psychologist named Harry Harlow devised a means to study whether food was the catalyst for bounding between mothers and infants. Much of what he did in this study is highly criticized for how unethical the studies were in the treatment of rhesus monkeys. Harlow separated rhesus monkey infants from their mothers and then created inanimate surrogate mothers for them out of wire and wood. Each of the infants became attached to its particular inanimate surrogate mother. Each infant monkey could recognize its mother’s unique face and preferred it above all others.

Following this, Harlow wanted to find out if these infant monkeys preferred bare-wire mothers of cloth-covered mothers. To do this, infants were deprived of food and then presented with a cloth mother and a wire mother, but there were two conditions. The first condition was the wire mother held a bottle with food, and the cloth mother held no food. The second condition was the opposite. The cloth mother held the bottle with food, and the wire mother had nothing.

Which mothers did the infant monkeys prefer? It was the cloth mothers they preferred. Not only did they prefer them, but they would cling to them for 17 to 18 hours straight. They would cling to their cloth mother even though it was the wire mothers who had the food. The infants would only visit the wire mother long enough to get food and then go back to their cloth mother. This led Harlow to conclude that there was a lot more to the bounding relationship between mother and infant than just food. It was contact and comfort that was essential to the psychological development and health of infant monkeys.

Another researcher, John Bowlby a British psychiatrist, years before believed that it was physical contact, love, and comfort from mothers that created the infant/child-mother bound in humans. Harlows study provided empirical evidence to what Bowlby already believed. Bowlby is credited with pioneering the work in attachment theory.

What does this study on infant monkeys mean for the development of human infants and children? Bowlby had a student named Mary Ainsworth who took Bowlby’s attachment theory further by conducting a study with human infants now known as the Strange Situation Protocol . This studied showed that infants/children will have different patterns of attachment based on how their primary caregiver cares for them. Ainsworth concluded in her study that there are three attachment styles:

1. Secure Attachment

2. Anxious-Ambivalent Attachment

3. Anxious-Avoidant Attachment

Secure attachment is seen in toddlers who will explore his surroundings freely while his parent (or caregiver) is present. Toddlers with secure attachment will also engage with strangers, but will be visibly upset when the parent (or caregiver) leaves. When the parent (or caregiver) returns the toddler is generally happy. Secure attachment is developed with parents who are responsive or sensitivity to a toddler’s needs from the time they are infants. Children with this attachment have confidence that their parents (or caregiver) will respond positively to their needs.

Anxious-Ambivalent Attachment can be observed in a toddler who will not explore their surroundings, they are typically wary of strangers with or without their parent (or caregiver) present. When the parent (or caregiver) leaves the toddler is often very distressed? When the parent (or caregiver) returns the toddler is generally ambivalent. This particular attachment is a likely result of a parent (or caregiver) who responds inconsistently or unpredictably to the toddler’s needs.

Anxious-Avoidant Attachment is a pattern of attachment that is observed in a toddler who avoids or ignores his parent (or caregiver). They show little emotion when their parent (or caregiver) leaves or when they return. Children with this attachment will not explore their surrounding regardless of whether or not their parent (or caregiver) is present. Researchers concluded that this behavior is a mask for distress. This distress was not visible to the eye, but was observed when monitoring children’s heart rate. It is theorized that anxious-avoidant attachment is a conditioned response strategy in children that de-emphasizes attachment needs. This conditioned response of de-emphasizing helps the child to "maintain a conditional proximity with the caregiver, …but distant enough to avoid rebuff." The cause of this is believed to be parents (or caregivers) who frequently do not meet the child’s needs, which leads the child to understand that his needs or emotions will have no influence over his parent’s (or caregiver’s) actions.

When making sense of all this, the nurture and nature argument helps in understanding this. Does child development happen because an infant at birth is preprogramed to grow and develop into a predetermined individual (the nature argument). Or does a child’s environment take a hold of a child as a blank slate (tabula rasa), which is then molded, as a by-product of the environment, into an adult (the nurture argument). Both arguments should be taken seriously since in reality both nurture and nature have a strong influence on the outcome of how a child turns out. In the context of attachment theory it is nurture that seems to be the more important of the two (nurture vs. nature). How a parent (mother or father) responds (nurture) will result in what kind of attachment a child develops. Along with this there have been longitudinal studies that have tracked infants/toddlers in each of the attachment styles. Interestingly, these studies found that there is a correlation between what attachment styles an infant or toddler has and to how well adjusted they become as adults. This correlation suggests that what we are doing as parents (particularly mothers, since they are typically the primary care providers for infants and toddlers) is very important and can have life long consequences for a child on into his adult years.