Many visionaries have developed theoretical frameworks that provide a basic general approach to understanding how children develop. Doherty and Hughes (2009) point out that early childhood progression is most often presented in terms of specific periods of time. This therefore tends to relate to the idea of ​​fixed and limited stages, strongly linked to chronological age, and furthermore providing a very specific order of change. The most commonly identified developmental periods are prenatal, infancy, early childhood, late childhood, and adolescence. Generalized theories of child development emerged in the 17th century, with John Locke's “Some Thoughts on Education” (1693) providing a basis on which a child is born as a “blank slate.” In contrast, Jean-Jacques Rousseau's "Émile" (1762) explored the idea that children are born with a moral sense. These two theorists provide the origins of generalized development, meaning that within these theories, children develop in the same way. However, using Gewirtz and Pelaez-Nogueras's (1992) criteria for evaluating theories, generalized theories do not account for individual differences that exist as children grow and develop. Thus, one might suggest that these general patterns are unlikely to be very useful. Behaviorism, on the other hand, asserts that the development of the individual can be achieved through observation and experiences of the environment. It states that development should be based on observations rather than speculation about cognitive processes, which are inherently unobservable. One of the earliest proponents of this theory was John Watson, who in 1913 published a paper ...... middle of paper ......t reflects a slow, steady change over time , or goes through clearly defined stages. Arguably, development should be seen as largely continuous, but with some stages characterized by "milestone" stages such as the initiation of walking, where this new skill is clearly different from the child's previous abilities. Early childhood development can be seen as due to many factors that have clear effects on aspects of its progression, such as diversity of environments and social contexts. Each child experiences a unique combination of genetic and environmental influences that show how children have their own distinctive abilities, suggesting that generalized patterns are not very useful indicators for considering an individual child's development except as a flexible framework within which the child's development can be taken into account. monitored.