Infant Parent Attachment A Critical Sensitive Period for Social Development

Illustrative examples of the concept of a critical/ sensitive period can also be found in the domain of social development. One particularly interesting example is the formation of the infant-parent attachment relationship.

Attachment is the strong emotional ties between the infant and the caregiver. This reciprocal relationship develops over the first year of the child's life, and especially during the second six months of the first year. During this time, the infant's social behavior becomes increasingly organized around the principal caregiver.

John Bowlby, a twentieth-century English psychiatrist who was strongly influenced by evolutionary theory, formulated and presented a comprehensive theory of attachment. In the late 1950s and early 1960s, he first proposed that there is a strong biological basis for the development of this relationship. According to Bowlby, the infant-parent attachment relationship develops because it is important to the survival of the infant and also provides a secure base from which the infant can feel safe exploring their environment.

Bowlby suggested that there was a sensitive period for the formation of the attachment relationship. This period is from approximately six months to twenty-four months of age and coincides with the infant's increasing tendency to approach familiar care-givers and to be wary of unfamiliar adults. In addition, according to Bowlby and his colleague Mary Ainsworth, the quality of this attachment relationship is strongly influenced by experiences and repeated interactions between the infant and the caregiver. In particular, Ainsworth's research, that was first published in the late 1960s, demonstrated that a secure attachment relationship is associated with the quality of caregiving that the infant receives. More specifically, consistent and responsive caregiving is associated with the formation of a secure attachment relationship.

If the period from six months to twenty-four months is viewed as a critical period for the development of the attachment relationship, the relationship must be formed during this specific period in early development. Alternatively, if this period is viewed as a sensitive period, the infant-parent attachment relationship will develop more readily during this period. After the sensitive period, this first attachment relationship can develop, but with greater difficulty. As in the case of language development, information about whether there is a critical or sensitive period for the formation of a secure attachment relationship comes from different sources. These sources include cases of infants who did not experience consistent caregiving because they were raised in institutions prior to being adopted.

The early research documenting such cases was published in the 1940s. This research consistently reported that children reared in orphanages for the first years of life subsequently exhibited unusual and maladaptive patterns of social behavior, difficulty in forming close relationships, and indiscriminately friendly behavior toward unfamiliar adults. The results of this early research contributed to the decline of such forms of institutional care. Furthermore, these results supported the notion of a critical period for the formation of the attachment relationship.

Research published in the 1990s has contributed to a modification of this notion of a critical period. These research results have come from studies of infants in Eastern Europe who were abandoned or orphaned and, therefore, raised in institutions prior to adoption by families in North America and the United Kingdom. These results have indicated that these adoptees were able to form attachment relationships after the first year of life and also made notable developmental progress following adoption. As a group, however, these children appeared to be at an increased risk for insecure or maladaptive attachment relationships with their adopted parents. This evidence, then, is consistent with the notion of a sensitive period, rather than a critical period, for the development of the first attachment relationship, rather than a critical one.



Curtiss, Susan. Genie: A Psycholinguistic Study of a Modern Day "Wild

Child." New York: Academic Press, 1977. Goldberg, Susan. Attachment and Development. New York: Oxford

University Press, 2000. Marvin, Robert S., and Preston A. Britner. "Normative Development: The Ontogeny of Attachment." In Jude Cassidy and Phillip R. Shaver eds., Handbook of Attachment: Theory, Research, and Clinical Applications. New York: Guilford Press, 1999.

Newport, Elissa L. "Contrasting Conceptions of the Critical Period for Language.'' In Susan Carey and Rochel Gelman eds., The Epigenesis of Mind: Essays on Biology and Cognition. Hillsdale, NJ: Erlbaum, 1991. Rutter, Michael. ''A Fresh Look at 'Maternal Deprivation."' In Patrick Bateson ed., The Development and Integration of Behaviour: Essays in Honor of Robert Hinde. New York: Cambridge University Press, 1991.

Ann L. Robson


Crying is a phenomenon that has puzzled people throughout the ages. People cry when they are sad, afraid, angry, in pain, or depressed, and yet people also cry when they are happy. Crying occurs in all emotions—it even contributes to the physiological well-being of an individual from birth to death. It is this versatility that makes crying so difficult to under stand. Furthermore, tears are not always a function of emotion. Crying is a very important aspect of infant development that acts as a tool for communication.

The Physiology of Crying

There are three types of tears. The first type is basal tears. Because the eyeball's surface is riddled with irregularities, basal tears create a thin coat over the eye which smoothes out the surface. This helps to protect and lubricate the eye. Without this lubrication, a person would see a very distorted picture, and it would be painful when the eyeball moves. The eye needs this coating all the time so the body must constantly replace these tears due to the loss caused by evaporation. A typical person will produce five to ten ounces a day. In addition, basal tears contain antibacterial chemicals.

The second type is irritant tears. Irritant tears occur when a person is exposed to freshly cut onions or has a foreign object in his or her eye. They are called irritant tears because they are produced when a foreign object, foreign chemical, or a simple poke irritates the eye. The body will also produce more irritant tears if the basal tears evaporate too rapidly and the eye is left with an insufficient amount to properly lubricate the eye. Ironically, a person with excessively watery eyes suffers from having dry eyes. It is the irritant tears that cause the watery eyes because the body is compensating for the lack of basal tears.

The third type of tear is psychic or emotional. These are the tears that well up inside and spill over the eyelid because of specific emotional states. They are definitely more voluminous than the two types of tears previously mentioned, and they have been found to have a different chemical make-up. William Frey has shown that these chemicals are linked to depression and stress. Frey believes that crying is the body's attempt of ridding itself of these pollutants, thus reducing stress and avoiding depression.

The Crying of Newborns

Newborn babies are not capable of crying for emotional reasons, but they share the same physiological properties of tears as mentioned above. For newborns, crying is a fundamental means of communication. Crying is not a matter of frustration caused by the baby's inability to express itself verbally—that would imply that the baby is aware of formal language but doesn't have the ability to use it. On the contrary, for the first few weeks crying is a reflexive property and is thought to have no emotional reasons. New-borns do not have the psychological capacity to hold an emotion such as fear or anger, so their cries are not a result of emotional imbalances. They are an

A crying toddler may depend more on internal feelings and moods rather than physiological needs. (Anna Palma/Corbis)

involuntary reaction to pain, hunger, and tiredness. Therefore, crying is the means by which the infant communicates these physiological imbalances to the caretaker.

Other physical imbalances may include excessive energy or tension in the muscles. Since newborn babies do not have a way to relieve stress, it is thought that crying is also a way for them to discharge the energy or tension.

The cries of a young newborn are short, high in pitch, and repetitive. They are short in duration due to the infant's underdeveloped lungs and muscles. The loudness and intensity of the cry can vary according to the newborn's needs. For example, crying due to hunger can be differentiable from crying due to pain. A hunger cry is rhythmic in nature which starts with a whimper and becomes louder and more sustained while a cry from pain starts with a shriek followed by a second of silence, as the baby gets a breath, and continues with more rigorous, high intensity cries. Studies have shown that mothers can identify the baby's need just by hearing the cry.

The Crying of Infants

Over the first few months psychological development allows the infants to move from involuntary cries, which speak exclusively of physiological de mands, to voluntary cries that now become an integral part of the infant's expressive and emotional development. The infant begins to show these psychological advancements by smiling and engaging with the mother. As a result, the infant now holds the capacity to cry because of anger and because of a need for attention.

During this time, the infant also undergoes physiological changes, which allows the infant more voluntary control over vocalization. The cries now become more sustained, and the pitch increases with a melancholy undertone. An anger cry is similar to a hunger cry in that it is rhythmic, but it is much more intense.

Between seven and nine months, the infant experiences a cognitive development that results in additional reasons for crying. For example, the baby now cries because of fear, whether it is due to strangers or a strange place. Separation from the parent can also elicit fear, which is commonly illustrated by a crying baby at bedtime. Furthermore, an infant's more active memory can lead to uncertainty of a situation. Crying ensues as the infant attempts to make sense of the unfamiliar events or surroundings.

The Crying of Toddlers

At seventeen to twenty-four months of age, the infant's self-awareness increases. Fear of failure, understanding of rules, and consequences if those rules are broken all become part of the child's psychological make-up. The child now cries because of an unfair situation such as wanting a toy that they cannot have. Henceforth, the source of crying depends more on internal feelings and moods rather than physiological needs, although they still retain the ability to unleash cries of pain in emergency situations.

Finally, the toddler becomes more mobile at this stage of development, therefore becoming more active and inquisitive of his or her surroundings. Frustration often sets in when he or she cannot perform a certain task correctly such as fitting a square peg into a round hole. Crying could be the toddler's method of reducing the stress and frustration of the situation.

The Duration of Crying

Infants typically cry between thirty minutes and two hours a day. Over two hours a day is too much and may be an indication of a physical ailment. It has been estimated that an infant will experience 4,000 crying episodes before the age of two. Many studies have been conducted around the world in an effort to determine whether or not different circumstances can affect the amount of crying by an infant. Surprisingly,

A crying toddler may depend more on internal feelings and moods rather than physiological needs. (Anna Palma/Corbis)

the results were inconclusive and in some areas contradictory. Despite the fact that these studies were conducted in different cultures, it was found that on average, extra handling, on-demand feeding, and other nurturing from the mother made little difference to the amount of crying or even to the specific times the babies cried. In fact, evening time proved to be the peak time for infant crying across the board, and gender was shown to have no impact on the amount or duration.

It has been shown through a longitudinal study of twenty-six infant-mother pairs in 1972 by Bell and Ainsworth that there does exist a relationship between crying and maternal response. Mothers who responded quickly to a crying baby over the first nine months actually yielded a baby that cried less after the nine-month period. It is thought that because of the prompt attention of the mother, the infant becomes more secure and less demanding of the mother's contact. Although other studies have substantiated these findings, it is not possible to generalize for all infants because amount of crying depends on the mother's responsiveness, personality, individual needs for love and closeness to mother, and a tolerance for boredom, jealousy, hunger, pain, and fatigue.

The Psychology of Crying

There are several different theories that attest to the psychology behind crying. As a child develops from adolescence through adulthood, the causes of crying encompass all aspects of the human emotional scale. Now a person can cry for a multitude of reasons that range from anger, pain, misery, grief, sorrow, joy, and intense pleasure. One can break down crying into three different levels that differ in psychological magnitude.

Level one consists of physiological conditions such as a broken arm or skinned knee. This is the same type of crying that infants utilize in the first few months of life. Even though infants develop out of this basic level and cry for other reasons, this type of crying still remains throughout the life of the person.

For example, a five-year-old child will be quick to shed tears due to a hurt knee or a twenty-five-year-old person may cry because of intense pain caused by an injury.

Level two entails moods and emotions. It begins when an infant cries from anger and develops further as more feelings are added to their emotional scale. As the child matures and an increase in self-awareness ensues, a sense of pride settles in and becomes a sensitive area. So, a fifteen-year-old may not cry as readily over a hurt knee, but he or she may shed tears due to humiliation.

Level three consists of deeper emotion usually associated with intense prayer, or a deep appreciation. For example, a thirty-year-old person could weep because of a powerful poem or due to a selfless display of humanity. Not all people can reach this level of crying. It demands a higher level of awareness of the world, self, and relationship between the two.


No other study has given conclusive proof that other species cry. Crying is unique only to humans. Perhaps that is the reason for the complexity of this phenomenon. Complex beings bring forth complex issues that may prove impossible to sufficiently understand. Because of its versatility and unbiased relation to age, gender, and culture, crying will continue to puzzle people for years to come.



Abell, Ellen. "Infant Crying: I'm Trying to Tell You Something.'' Available from index.html; INTERNET. Lester, Barry, and Zachariah Boukydis C. F. Infant Crying: Theoretical and Research Perspectives. New York: Plenum Press, 1985. Lutz, Tom. Crying. New York: W. W. Norton and Company, 1999. Murry, Thomas, and Joan Murry. Infant Communication: Cry and

Early Speech. Houston, TX: College Hill Press, 1980. Sammons, W. A. H. The Self-Calmed Baby. Boston: Little Brown, 1989.

Timothy K. Loper

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