Physiological preterm birth is not the only cause of “Secondary Altriciality” in humans, the need to accommodate the development of complex plasticity in the evolution of psychosocial relationships is also a cause of this

Physiological preterm birth is not the only cause of “Secondary Altriciality” in humans, (but also) the need to accommodate the development of complex plasticity in the evolution of psychosocial relationships is also a cause of this

As is now pointed out in developmental psychology, the developmental phenomenon that human beings are born in a state where the infant is deeply in need of its mother,but the cause which made this appearance no only means that “if fetus’s brain is sufficiently developed, fetus will be inability to through the birth canal well”. Because, if we look at it from a more macroevolutionary perspective, we see not only a tributary comparison of the differences between the Carnivora and the Primates, but also a progression from fish and amphibians, which expelled eggs that were completely self-sustaining through in vitro insemination, through the Reptilia, where eggs were nurtured in the body and some degree of maternal participation began, to the Ornithopoda and Birds, with their incubation and rearing of eggs and the act of child rearing. As we can see from the evolutionary course of the organisms, the offspring of the organisms are placed in a more and more plastic nurturing relationship as they evolve, and through this plasticity, the ability to adapt more flexibly to the environment is developed. Through this plasticity, the children of primates are able to flexibly adapt to its environment, while also having the possibility of developing in a more flexible manner. And indeed, if we look at the primates, we can see that primate animals in their infancy are more detached and better adapted for survival than carnivores, when the same times, as Harlow's famous "series of psychological experiments on small monkeys that found a link between attachment and development," in fact, compared to Carnivora, Primates are more dependent on nurturing relationships, and the psychosocial meaning of attachment is much more complex.

In the case of primary nidifugous species such as lagomorphs and carnivores, the parent-child relationship seems to be more purely controlled by hormones compared to the nidicolous primates. The social and psychological love and attachment are weaker, and the complex interpersonal relationships and profoundly psychological meaning of love in attachment and sociality have been present. The early object relationships that form the fundamental basis for such complex, broad, and deep psycho-social connections can be considered precursors of a psychological system that includes such complex meanings. Furthermore, the parent-child relationship in infancy, which can be considered an early interpersonal relationship and precursor of a psychological system that includes such complex meanings, along with related developmental aspects, are such that "infants are unable to be independent and various physiological functions depend on the care and support of the caregiver, which is referred to as secondary nidicolous physiological prematurity." This phenomenon, while solving the contradiction with the narrow birth canal for brain development due to physiological prematurity, is something I believe cannot be explained by that reason alone.

The nurturing received from the mother also involves linguistic communication, which provides and promotes high-level schemas of personality and intellect, aiding in the learning of social relationships. This psychological development given to infants through the dialectical tension of the "infant-caregiver" relationship is never something merely received during fetal development. Thus, infants are not only nidicolous because their heads are not yet large enough to pass through the birth canal. In the communication with the mother, skinship is cultivated, and from this skinship, intimate relationships of attachment mature through actions like caressing and breastfeeding. These behaviors are prototypes of abundant sexual activities and the rich pleasures and social psychological communication associated with them. They represent just the first steps, with the overall outline still undefined. This line of thought is largely consistent with the view that the physiological prematurity of infancy, which corresponds to 21 months, represents a period of maximum plasticity. This period, which Erikson identified as the developmental task of forming "basic trust," is when the foundation of the deepest personality is solidified. The experiences during this time are not innately fixed but filled with plasticity. This very plasticity allows the experience of "basic trust" to function in various changing situations without being limited to innate instinctual forms.

From the perspective of biological evolution, newborns of reptiles, birds, and mammals transition from being born with independent functions and handling the environment on their own to being cared for by their mothers or both parents, receiving nurturing and education from the parental generation. Unlike the innate and developmental forms of reptiles, amphibians, and fish, where the young take on instinctual forms directly based on their genetics, birds and mammals acquire advanced communication functions as they evolve (enhancing their postnatal learning abilities). This involves functions that go beyond the instincts of the archicortex and paleocortex, regulating signal feedback between neurons. Through educational communication between parents and offspring, development is influenced by providing environmental stimuli and materials, fostering meanings through postnatal and psychological feedback between neurons that transcend instincts. This complexification mechanism represents a significant and decisive force in psychological-social development, underscoring the profound meaning of complex neural experiences. This foundational cause elucidates why the parent-child relationship increasingly assumes a critical role in the course of biological evolution.

At last, the proportion of innate fixed forms decreases, it means that more environmental adaptations are entrusted to active development and maintenance through postnatal plasticity and selectable interactions. This flexibility in environmental adaptation serves as a foundation for the formation of meanings in a rich and complex "psychological-social" life. The ability to develop flexibly and abundantly through plasticity establishes the basis for complexity, active choices, self-realization, and self-ability. The logic described in this text ultimately points to such phenomena and meanings.