Introduction

In general, a 'critical period' is a limited time in which an event can occur, usually to result in some kind of transformation.

Critical periods in psychology and biology are crucial to an organism and work hand in hand. During these periods imprinting occurs. The most commonly known of these is puberty which, in most animals, is the passage between pupa form and fully functioning adult. It is characterized by many developments in Chomsky 's Erickson's, Piaget's, Kohlberg's, Freud's and just about any other Developmental psychologist. Indeed, each organism's Deoxyribose Nucleic Acid (DNA) codes for a biological clock which relates to when the organism will mature. Psychology (Classical Greek: psyche = soul or mind, logos = study of) is an academic and applied field involving the study of behavior, mind and thought and the neurological bases of behavior. ... Main articles: Life All organisms (viruses not included) consist of cells, which in turn, are based on a common carbon-based biochemistry. ... Imprinting has different meanings in: Genetics: see imprinting (genetics) Psychology and ethology: see imprinting (psychology) In addition, the term imprint is used in publishing. ... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ... Chrysalis of Gulf Fritillary in Georgetown, South Carolina Pupation of Aglais urticae A pupa (plural: pupae or pupas) is the life stage of some insects undergoing transformation. ... The term adult describes any mature organism, but normally it refers to a human: one that is no longer a child / minor and is now either a man or a woman. ... Avram Noam Chomsky (born December 7, 1928) is Institute Professor Emeritus of linguistics at the Massachusetts Institute of Technology. ... Erickson can refer to several persons: Arthur Erickson - Canadian architect Dennis Erickson - former coach of the NFLs 49ers and Seahawks Ethan Erickson - American actor John Edward Erickson - governor of Montana John R. Erickson - American author Leif Erickson - American actor Milton H. Erickson - American psychiatrist specializing in medical hypnosis Robert... Piaget has several meanings: Jean Piaget - Professor of psychology Piaget SA - A Swiss watch making and jewellery company This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Kohlberg is the name of three municipalities Kohlberg, Baden-Württemberg in the district Esslingen, Germany Kohlberg, Bavaria in the district Neustadt (Waldnaab), Germany Kohlberg, Styria in Styria, Austria Persons named Kohlberg Lawrence Kohlberg, developmental psychologist Jerome Kohlberg, Jr. ... Sigmund Freud His famous couch Sigmund Freud (May 6, 1856 - September 23, 1939) was an Austrian neurologist and the founder of the psychoanalytic school of psychology, a movement that popularized the theory that unconscious motives control much behavior. ... Developmental psychology is the scientific study of age related behavioral changes which occur as a child grows up. ... Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... A biological clock enables an organism to anticipate periodical changes in their environment. ...

Linguistics

In linguistics it is believed that there is a 'critical period' of the first few years of life, in which individuals can easily acquire language if presented with adequate stimulus. Pinker (1994) states that “acquisition of a normal language is guaranteed for children up to the age of six, is steadily compromised from then until shortly after puberty, and is rare thereafter” (p. 293). The evidence for such a period is rather thin, and stems largely from theoretcal arguments and analogy to critical periods in biology such as visual development, but nonetheless is widely accepted. An important theorist for such a model is Noam Chomsky, who infers the existence of a "language acquisition device", or a biologically 'hard-wired' capacity to acquire language. This article needs to be cleaned up to conform to a higher standard of quality. ... Avram Noam Chomsky (born December 7, 1928) is Institute Professor Emeritus of linguistics at the Massachusetts Institute of Technology. ... The Language Acquisition Device (LAD) is a part of the human brain theorized by Noam Chomsky which allows humans to acquire languages. ...

The stages of such a period can be divided as follows:

• The babbling stage is reached by most infants at three to four months of age. Through discriminating sounds, reading lips, perhaps vocal chords, they may utter incoherent sounds. By ten months the infants' incoherent sounds usually reflect the language(s) used in the household as evidenced by Janet Werker (1989) and her experiment regarding Hindi "t" Japanese "r's" or "l's".
• The one-word stage, reached normally around twelve months, is characterized, as the name implies, by single word sentences.
• The two-word stage, reached at around twenty-four months, is speech by children which reflects a Telegraph or is called Telegraphic speech in which the child might say "give water" with varying emphasis for the desired response.
• Soon enough the child speaks in relatively coherent sentences, in some cases full sentences,

The theory is extended to a critical period for learning a second language. Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ... Telegraphic speech, according to Linguistics and Psychology, is speech during the Two-word stage of Language Acquisition in children, which is laconic and efficient. ... A second language is any language other than the first, or native, language learned; it is typically used because of geographical or social reasons. ...

The theories of B.F. Skinner regarding acquisition of language are in opposition to such a model, and state that acquisition occurs through operant conditioning. Burrhus Frederic Skinner (March 20, 1904 _ August 18, 1990) was an American psychologist and author. ... Operant conditioning, so named by psychologist B. F. Skinner, is the modification of behavior (the actions of animals) brought about by the consequences that follow upon the occurrence of the behavior. ...

References

• Pinker, S. (1994). The Language Instinct. New York: Morrow.