Critical or sensitive imprinting period

 

In ethology imprinting was introduced in research on animal behaviour. It was based on recognising innate aspects of behavioural traits, developing in critical (fixed) or sensible (flexible) time frames. It started with birds and established itself next in research on mammals. Concepts were learning strategies and a host of social behavioural interactive processes in H. sapiens were mentioned by Eibl-Eibesfeldt ^{8. 9}
A problem was and in a sense still is tabula rasa ^{18 35} for human development described by John Locke (1632 Ð 1704):

At one extreme, we have John Locke's idea of tabula rasa that proposes that the minds of newborn infants are blank slates that will be differentiated and altered only through sensory experience. Modern biological determinism represents the other extreme. In its strictest form, this ideology suggests that behaviors are inherent and innate, resulting from the expression of genes. Most intellectuals subscribe to a view somewhere between these two extremes, on the gradient of a controversy that is still a hot topic of debate in many intellectual fieldsÓ(cursive Meijers).

 

This tabula rasa still is accepted for our little babies. But a variety of faculties to receive and abilities to manipulate or process the content as Knezek¹⁸ describes, it resembles innate imprinting possibilities (Meijers) in sensitive periods. Reported most for humans is language adapting.  A problem there exists in different opinions, shown by Johnson and Newport (1989), cited in Purves ET al.³⁰:

Many animals communicate by means of sound, and some (humans and songbirds are examples) learn these vocalizations. There are, in fact, provocative similarities in the development of human language and birdsong (Box B). Most animal vocalizations, like alarm calls in mammals and birds, are innate, and require no experience to be correctly produced. For example, quails raised in isolation or deafened at birth so that they
never hear conspecifics nonetheless produce the full repertoire of species-specific vocalizations. In contrast, humans obviously require extensive postnatal experience to produce and decode speech sounds that are the basis of language.

Fig. 4 Decline in language ability

A critical period for learning language is shown by the decline in language ability (fluency) of non-native speakers of English as a function of their age upon arrival in  the United States (fig. 4). The ability to score well on tests of English grammar and   vocabulary declines from approximately age 7 onward.Ó

As far as language is concerned, the process begins earlier than three years. The first year is more accepted but does not mean language. The essential language-imprinting phase is a long 'critical period'  (fig. 4) but for baby swimming we have to do with a very short 'sensible period'. Able swimming can  still be realized years later but it takes grownups a lot more time to achieve results. The discussion between SMF IP and YMCA in Pediatrics ^{5 11} shows something similar, connected with time lags for aquatic adaptations at different ages.
The YMCA and Infant Swimming Resource (ISR) look at little babies able surviving  to stay afloat at an age younger than one year and mention success in one to six months.
The SMF and IP Committees defend real swimming abilities and choose two to four years of age as starting point for training and state that 55 to 58 month are needed to complete this process, in fact a year or more. It shows that there should be cooperation and more research to overcome conclusions that differ until now substantially.
 

ISR Harvey Barnett presented his considerations in  A Behavioral Approach to Pediatric Drowning Prevention at University of Oklahoma Health Science Centre, March 5 2009 ³. The question to uncover apparent reflexes of very young children adapting to aquatic circumstances absolutely differs to that about two to four years old children. The early starting point shows quick and easy aquatic adaptation of newborns and toddlers. Barnett stated like others that such development is connected to early psychomotor abilities.

http://tvs-media-ex.ouhsc.edu/ with dr Barnett

Things are changing (2011). The mentioned organisations are more consenting as this news item shows:

Doctors state ok for babies to swim