The concept of critical period was first proposed by Austrian ecologist Conrad Lorenz (1937). In his observation of the natural habits of birds, he found that newly hatched young birds, such as chickens, geese, etc., would learn to chase their own kind or non kind within a short period of time after birth. After this period of time, they could no longer learn such behaviors or imprint their mothers. This period of time is very short, so it is called the critical period of human beings, also known as the optimal period, sensitive period Critical period, turning point. Later, psychologists borrowed this kind of research into the study of early childhood development, and proposed the critical period of children's psychological development. For example, 2-3 years old is the critical period for children's oral language development, and 4-5 years old is the critical period for children to learn written language. [1]
The critical period of language development
Early childhood is the best time to master oral English. Under normal living and educational conditions, the development of oral English can be divided into three stages: infant stage, mainly the stage of phonetic development; Infancy, mainly the stage of mastering vocabulary; In early childhood, the ability to master pronunciation, grammar and oral expression has developed rapidly at the age of 3 to 4, and the ability to basically master oral before the age of 6. Some foreign scholars believe that the period from the age of 2 to adolescence is the critical period or the most appropriate period for speech development. It is believed that the language potential of both sides of children's brains is equal from birth to 2 years old. From the age of 2 to adolescence, due to maturity and environmental factors, children's brain has formed asymmetry, and the formation process of brain asymmetry contributes to the maturity of language, so it is a critical or optimal period for speech development. Some scholars in China also believe that the key period for language acquisition is from 2 to 12 or 14 years old. After 12 or 14 years old, it is difficult to acquire the first language. In addition, some scholars have proposed that 2-3 years old is the key period for children to learn oral language, and 4-5 years old is the key period for children to start learning written language.
Is there a critical period for attachment
The critical period is the period when individuals have the greatest sensitivity or readiness to the development of certain skills or behavior patterns. It is impossible for a special skill or behavior model to appear before the critical period begins. When the critical period has passed, it is not impossible to form a certain skill, but it is extremely difficult. The successful emergence of any behavior has a critical period of development, which depends on the biological preparation of the organism and the support of the environment.
Conrad· Lorenz was the first ecologist who compared the critical period of forest development and behavior development. Lorenz described the imprinting process of social attachment of birds. In this process, the birds have established a more permanent emotional bond with their mother. When the mother is away, the bird prints other available targets, including a mold of its mother or a person. For birds, the critical period begins when they can walk, and ends when they begin to fear strangers. After this period, no new models or species can replace the printed objects.
Shortly after the baby was born, the parents' attachment to the baby became single-minded; Parents are unwilling to let other infants of the same age replace their own children. Is there a time period for infants to form attachment with their earliest caregivers? The most direct way to test this problem is to separate the baby from his mother and observe the results of the emotional bond between the baby and the new caregiver. Although such an experiment is immoral, the evidence for this problem must come from the real life situation where the relationship between children and children is broken.
Leon Yarrow (196319641970) observed 100 babies who left their birth mothers and followed their adopted mothers. Babies separated from their birth mother at 6 months or earlier showed the least distress. If their physical and emotional needs can be continuously met, then they will not show excessive anger or depression in the process of separation. On the contrary, at 8 months or later, all babies who left their birth mother and came to the adoptive mother showed strong negative reactions, including angry resistance and withdrawal. These babies think that it is very stressful that their early relationship is destroyed.
John Bobby's later research focused on adolescents who repeatedly transferred from one adoption family or social institution to another. These children have never had the opportunity to form a lasting and stable attachment with an adult caregiver. In adolescence, they are described as lacking in emotion and unable to form close interpersonal relationships with others. Recent research shows that the replacement rate of caregivers in social institutions is very high. Children who spend their infancy here show confusion in their social functions, including indiscriminate friendship, difficulty in forming close relationships, and difficulty in finding emotional support from peers (Rutter, 1995). It can be seen from these practical examples of mother infant relationship destruction that about 6 months is the critical period for infants to form attachment.
When will this critical period end? Twenty four months ago, infants had established a good attachment relationship. A follow-up study shows that the quality of attachment is consistent from 12 months to 18 months, from 12 months to 20 months, and from 12 months to 6 years old (Main, Kaplan， S- Cassidy，1985）。 Is it true that after a certain period, secure attachment can no longer be established? If there is no opportunity to form a consistent interpersonal relationship with a loved adult, as in the case of teenagers studied by Bobby, attachment cannot be formed. If infants live in social institutions with high care quality but high staff turnover rate when they are one year old and are adopted when they are two years old, they can establish safe attachment with adoptive parents. However, for children aged 8 and 16, the difficulties in interpersonal relationships with peers are the same after adoption as those still living in social institutions (Hodges&. Tizard, 1989). Lack of consistency of care in infancy, such as care received in social institutions and changes from one adoptive family to another, may lead to long-term and continuous confusion in the establishment of interpersonal relationships among infants. Even if these infants later form a safe attachment to their caregivers, the problem will still exist. [2]
