Normative Development

The concept of normative development is a complex and much debated one. It is an issue that is continually researched by scientists and psychologists alike as they seek to understand the changing processes that shape development over the human lifespan. One of the fundamental questions that underlie this research is whether normative development actually exists. The volume of statistical data on normative development is constantly changing and growing adding greater complexity of the issue.

Normative development concerns the typical (normal) capabilities, as well as limitations, of humans of a given age within a given cultural group. It indicates a typical range of what can be expected at a given time. These are generally referred to as developmental milestones to indicate steps in certain abilities that should be reflected at different ages, as determined by supporting research. In this way, normative development is important because it allows us to understand what to expect at different ages (Sigelman and Rider, 2006).

The works of different theoretical viewpoints will be examined, each with differing perspectives on the nature of human development. The degree of variability between these theories brings into question the viability of normative development.

The changes and continuities of human development are examined across three broad areas. These are the physical growth of the body, organs and motor skills; the cognitive abilities such as language, perception and memory; and the psychosocial development, which includes social interactions, personality traits and identity (Sigelman & Rider, 2006).

Human growth, development and aging are guided by a unique genetic program, set into action by the brain and hormones released by the endocrine system. Areas of physical development include brain development, locomotor skills and sensory capabilities. including perception. Developmental phases studied across the lifespan are the infant, from birth to two years, the child from approximately three to twelve years, the adolescent of twelve to eighteen years and finally the adult; young, middle, and elderly. The endocrine system, together with the nervous system, is fundamental to growth during childhood, sexual and physical maturation of the adolescent, performance and aging over the lifespan (Sigelman & Rider, 2006).

Jean Piaget’s Cognitive Development Theory is still widely influential today and remains directly relevant to contemporary theories on child development. Piaget proposed that all children progress through four universal, stage-like phases, and believed development was predominantly biological-based although he did recognize environmental-learned experience. He considered humans to be adaptive and active in their cognitive development, and to construct new understandings through their explorations. These developments are qualitative and replace former strategies at each new stage (Sigelman & Rider, 2006). By arguing these stages were similar and common to all children, Piaget espoused normative development.

Piaget’s first stage, from birth to two years, is the sensorimotor period. Infants explore and discover their world using their innate senses and motor skills, solving problems through experimenting. By constructing organized patterns of thought and action - schemes - they are able to make sense of their world. As children’s knowledge and experiences change, these schemes adapt and change as a result of the ensuing mental conflict and the interpretation of new information. According to Piaget, they learn to construct mental symbols, leading to more purposeful thought and early language, such as babbling and cooing (Sigelman & Rider, 2006).

Infancy is a time when most fundamental capacities emerge and develop and on which the rest of the lifespan is determined, so it is a crucial period. Babies are born with reflexes, sensory and perceptual capabilities and are able to learn through their experiences. Motor skills are closely connected to perceptual-cognitive developments. Newborns are checked for normal physical development using the Agpar test for heart, colour, reflex, muscle and respiratory (Sigelman & Rider, 2006).

The critical period for brain development is during late pregnancy and early infancy. Although normal genes roughly determine normal functioning, early experiences establish the brain’s patterning. Research has shown that babies born into lower socio-economic environments and institutions are at a disadvantage. This is possibly due to poor maternal nutrition, lack of healthcare and advice, and lack of a stimulating environment. Physical and emotional conditions surrounding the pregnant and early infant environment can determine and influence whether a baby develops within the developmental norm. Environmental hazards such as pollutants, and exposure to drugs and alcohol can have adverse affects on development that impact across the lifespan. Risks include low birth weight, mental retardation and congenital abnormalities, such as spina bifida and Down syndrome (Sigelman & Rider, 2006).

There are also sensitive periods within early infancy in which normal vision, perception, hearing and language development can be compromised. Abnormalities can have profound affects on the development of close family members too (Sigelman & Rider, 2006). Clearly, considering the complex clinical reality of infant development and factors that cannot be predetermined, Piaget’s theory is too restrictive.

Infants and children most likely to experience stable normative development benefit most from a stimulating loving home environment. In his Attachment Theory, psychiatrist John Bowlby argued that humans are biologically disposed to forming close affection ties and behavioral systems that help us normalize our emotions. A secure early attachment to our primary caregiver has been shown to have a positive impact on an individual’s social development and the quality of attachment during infancy can influence the quality of relationships across each subsequent developmental period. Those infants and children, who never form a stable attachment bond through circumstances such as parental absence, are more likely to suffer relationship issues throughout the lifespan. Early emotional strain can raise stress hormone levels in infants and this can impact on their neural development. Evidence shows social relationships affect health and wellbeing, so dysfunction has a direct impact on our development (Sigelman & Rider, 2006).

Psychologist Albert Bandura’s Social Cognitive Theory stresses the role our social interactions have on our development. Bandura believed that by observing other people we construct and memorise mental symbols, which we later use to direct our behaviour. He emphasized the importance of active information processing in behavioural and learning development. By observing the potential consequences of others actions, learners will then decide whether to imitate (Bandura, 2001).

This can account in part for language progression. By listening to talking, infants begin to process words. They then imitate other people’s speech, and if this behaviour has favourable consequences, they are more likely to have advanced early language development (Sigelman & Rider, 2006). Infants with older siblings also show superior word comprehension, signifying the influence of the social-interaction element (Fletcher-Flinn & McCormack, 2000).

The core feature of Bandura’s theory is that “people play a part in their self-development, adaption, and self-renewal with changing times” (Bandura, 2001, p2). Self-efficacy, the belief that one can successfully create a desired outcome, ultimately affects what courses of action people choose, and so affect development. In this way, development is context specific, multi-directional and can differ at all ages. He rejects the notion of universality and believes developmental change occurs gradually and continuously (Sigelman & Rider, 2006).

In Piaget’s theory, pre-school children aged two to seven, are in the pre-operational stage. Children’s physical growth is steady and they master more advanced motor skills as their muscles strengthen and their agility improves. Their symbolic capacity flourishes as they play and develop language. Creativity rises but appears to lessen at the advent of school. They are unable to think logically and view the world egocentrically. They become more aware of gender and develop early theory of mind, beginning to understand people have different mental states that cause certain behaviours. Dependent on a normal brain, this ability to understand others and adopt their perspective generally leads to better social integration. Piaget believed it is through the interaction with their peers, not adults, that children advance their cognitive development. This appears true for children’s social cognition too, with evidence showing children with siblings have a higher developed theory of mind (Sigelman & Rider, 2006).

In contrast to Piaget, the Russian psychologist Les Vygotsky’s sociocultural perspective emphasizes the role of culture and society in cognitive development. Children learn through interaction with a skilled helper and in response to cultural influences. Language is a key learning tool the child internalizes into personal thought processes, problem solving and language development. As statistics show, in children less than three years, large differences in vocabulary are apparent due to quantity and quality of language they are exposed to. Unlike Piaget who believed guided training does not increase development, Vygotsky’s perspective relies on the premise that children learn and advance through teaching. Evidence of special preschool education services for disadvantaged children shows better performance in cognitive and social skills, suggesting that children can improve their skills if given a stimulating learning environment (Sigelman & Rider, 2006).

The Bayley Scales test normal mental, motor and behaviour development of infants and are thus a diagnostic tool for neurological problems. Children who suffer autism have trouble developing theory-of-mind, empathy for others and experience socialising problems (Sigelman & Rider, 2006). Their development and that of their families will deviate from the expected norms.

The rapid growth of electronic technology we are experiencing in the 21st Century will surely advance children’s early cognitive abilities in ways not studied by Piaget and raises doubts as to what we can define as normative today (Bandura, 2001).

In Piaget’s concrete-operational stage, children ages seven to eleven begin to reason logically and deductively, thereby improving memory skills and problem solving. Their knowledge base and ability to process information increases. Piaget stated that these cognitive developments are qualitative and occur almost abruptly with each stage, whereas information-processing theorist Robert Siegler argues that these changes occur gradually and variably over time. His “overlapping waves theory” suggests children adapt and select their strategies to tasks as needed (Sigelman & Rider, 2006, p230).

Piaget proposed children develop a “heteronomous morality”, believing in the sacredness of rules, with little consideration of intentions (Sigelman & Rider, 2006, p328). More recent findings suggest children are able to differentiate between rules and their level of social cognition is more sophisticated then Piaget expected (Sigelman & Rider, 2006).

The issue of good nutrition is still crucial to normal development and those children from low socio-economic households are shown to be disadvantaged (Sigelman & Rider, 2006). Obesity and the associated disease type 2 diabetes are becoming more prevalent and are one of the biggest health challenges facing western developed nations. Traditionally considered a disease of adults, type 2 diabetes is increasingly diagnosed in children in parallel to rising obesity rates. Another by-product of 21st Century living, the epidemic raises questions as to what constitutes a normative physical development (Australian Institute of Health & Welfare).

In Piaget’s formal-operations stage, from approximately twelve years onwards, adolescents’ cognitive abilities improve as the brain increases, with the beginning of abstract and hypothetical thought, and increased attention span. During adolescence, strong bonds with peers are formed and many experience with intimate relationships. They develop more advanced social perspective-taking capacities, entering what Piaget termed the “Autonomous morality” stage, where they start to take into account others intentions and view rules as changeable contracts (Sigelman & Rider, 2006, p383).

In his social cognitive perspective, Bandura stresses that our moral cognition is tied to our moral behaviour. This behaviour is learned through observation, and is reinforced by the consequences of our behaviour. It is monitored internally by our individual standards of morality. So if we have not internalised strong moral standards, we are more likely to become involved in immoral behaviour. Personality traits and resulting behaviours alter and adapt according to specific social environments. Adolescent’s ability to think more independently can also lead to greater confusion and rebellion. This is particularly evident in adolescent’s often reckless conduct and risk taking that can have huge implications on their future development (Sigelman & Rider, 2006).

Adding to the internal confusion is the dramatic physical changes that occur. A surge in growth hormones creates a growth spurt and muscles develop rapidly. Both sexes experience sexual maturation, or puberty. The psychological effects of puberty are significant as teenagers grapple with their sexual changes and increased levels of hormones. Adolescents often become preoccupied with body image and how they are perceived and a period of internal conflict and self-identity emerges. Evidence also indicates the age at which adolescents experience puberty has a significant affect on all aspects of their development, including sense of identity, academic performance and social confidence. Levels of cognitive development, home and cultural environment and scope for opportunities create a diverse range of experiences and differing developmental results (Sigelman & Rider, 2006).

Research has shown that some adults do not reach or use Piaget’s final stage, formal-operational thought, especially in remote rural cultures where social experiences are limited. There is also evidence that people swing between Piaget’s later stages depending on the social and environmental context (Sigelman & Rider, 2006). This questions Piaget’s assertion of universality and discontinuity.

Although Piaget suggested that cognitive development was mastered by age eighteen, research indicates some adults reach another level, known as postformal thought. The qualitative difference is relativistic thinking, that is, “… understanding that knowledge depends on the subjective perspective of the knower” (Sigelman & Rider, 2006, p 206).

In young and middle adulthood, cognitive abilities strengthen and intelligence stabilizes. In later adulthood, some mental and physical capabilities slowly start to weaken. The decline in neural functioning affects cognition and perception, with the most universal changes in capacities being visual and auditory.
However self-esteem and identity seem to remain stable. As we age, disease and physical ailments increase although good nutrition and keeping physically active contribute to healthy development. Keeping mentally alert and socially active can also slow down declines in cognition. Deterioration of the nervous system occurs leading to degrees in memory loss, and often alzheimers. There are considerable differences in aged development, while many older adults remain alert and active across most of the lifespan, others contract debilitating diseases (Sigelman & Rider, 2006). An expected normative development, then, appears problematic.

Universal stage theories, such as Piaget’s, have been formulated within specific social contexts and value systems. A normal developmental milestone expected in one culture may not be valued or relevant in another. These developmental norms are also influenced by factors such as the group studied, culture and generation and so conceal wide variations among the subjects. Criticisms of many studies include a cultural and gender-bias, and a lack of consideration for the relevant historical and social contexts (Sigelman & Rider, 2006). While Piaget has been hugely influential in furthering understanding cognitive development, particularly in children, and there may be some degrees of universal growth, such theories fail to factor in our unique experiences, the dynamics of change and the significant individual variabilities to these norms as evident in our world.

As German psychologist Paul Baltes (1980) successfully argues, developmental-processes can occur at any age in life and are influenced by historical, biological, sociocultural and unexpected life events that can account for substantial individual variation.

Bandura’s social cognitive theory takes into account this complex interplay of individual biological potentialities, different psychosocial influences and the adaptive modes of behaviour people adopt to shape their development (Bandura 2001). People are proactive and “…bring their influence to bear on how they live their lives” (Bandura, 2001, p13).

Today, with the advance of genetic research and a more sophisticated understanding of human development, the focus of development now lies in the fluctuating balance of gene-environment interaction (Sigelman & Rider, 2006).
The study of identical and non-identical twins has advanced scientists’ findings. By studying twins reared together and apart, scientists are able to better estimate the degree to which heredity and environment contribute to an individual’s makeup (Wright, 1997, p1). So although it will always be problematic establishing beyond a doubt the exact degree of influence, the sheer scale of contributing and conflicting factors that shape our development means there will remain ambiguity concerning normative development.

“Assuming that the infant has normal opportunities to explore and experience the world, the result will be a normal brain and normal development” (Sigelman, 2006, p155). The degree to which this can be true depends greatly on seemingly immeasurable, complex and changing conditions.

At best, by attempting to define normative development, theorists offer guidelines that aid us in understanding the many developmental possibilities and alert us to the vast differences in human development. But the different sources of influence such as genetics, nutrition, rearing, social class, temperament, ethnicity and culture that determine our development are too diverse and complex to allow for a truly predictable normative development.