Critical periods in the organization of systems

Abstract

The general theory of critical periods applies to organizational processes involved in the development of any living system on any level of organization and states that the time during which an organizational process is proceeding most rapidly is the time when the process may most easily be altered or modified. Complex organizational processes involving 2 or more interdependent subprocesses may show 1 to several critical periods, depending on the time relationships of the subprocesses. The nature of the relationships between interdependent processes operating on different levels is again dependent on time and is a more meaningful formulation than that of the old "innate-acquired" dichotomy. These theoretical considerations lead to the conclusion that understanding a critical-period phenomenon rests on analyzing the nature of the organizational process or processes involved. An example is given in a review of research on the critical period for primary socialization (social attachment) in the dog. Evidence that attachment has taken place consists of discriminative behavior in relation to familiar and unfamiliar objects and rests on a minimum of 3 processes: 1) organization of the separation distress response; 2) visual and auditory sensory capacities; and 3) long-term associative memory capacities. Once these capacities are developed, the overall attachment process proceeds very rapidly (the critical period for such attachment). Thus the critical periods for the organizational subprocesses precede or slightly overlap that for the overall process. Deeper analyses of these processes must rest on neurophysiological research. The theory of critical periods is a general one that should apply to any developmental organizational process which proceeds at grossly different rates at different times. General Theory of Critical PeriodsAs presently understood, the theory of critical periods is a general theory of organization. Therefore, it is applicable to a wide variety of organizational phenomena, ranging from embryonic development to the formation of organizations between nations. The only exceptions are those based on the nature of specific organizational processes-those that are continuous and proceed at uniform rates-rather than on the entities which are being organized. Such exceptions are relatively rare and, therefore, one may safely assume that any new or unknown organizational process has a high probability of showing a critical period. The theory of critical periods is thus related to and should be compatible with other theories of organization.

Morphological Development of Thick-Tufted Layer V Pyramidal Cells in the Rat Somatosensory Cortex

“…The former happens within the first 2 weeks after birth, which possibly reflects intrinsic growth programs for the initiation of brain functions. The latter happens afterward during the critical period of primary socialization or experience-related learning (Scott et al, 1974). In agreement with this study, our study also indicates two modes of morphological changes of TTL5 cells in the somatosensory cortex.…”

Endocrine Modulation of the Adolescent Brain: A Review

“…It is in this stage that organizational modifications occur. 33 However, it has been observed that a series of important processes involving organizational development of the nervous system also occur during adolescence. 34 During this period, sex steroids produce a structural remodelling of the circuits that determine the behavioral response to hormonal or sensory stimuli in adulthood.…”

Puberty and adolescence as a time of vulnerability to stressors that alter neurobehavioral processes

“…Multiple sensitive periods exist for the organization of the brain and nervous system, primarily occurring during periods of rapid developmental changes (Scott et al, 1974). One of the most well-studied and best-characterized periods is that of the perinatal period in rodents.…”