Section 1: Introduction to Lifespan Development
1.2 Defining Lifespan Development
- Describe lifespan development and its three domains: physical, cognitive, and psychosocial development
- Explain key lifespan development issues about the nature of change: continuous/discontinuous, one course/multiple courses, and nature/nurture
Domains in Human Development
Physical Domain
Many of us are familiar with the height and weight charts that pediatricians consult to estimate if babies, children, and teens are growing within normative ranges of physical development. We may also be aware of changes in children’s fine and gross motor skills, as well as their increasing coordination, particularly in terms of playing sports. However, we may not realize that physical development also involves brain development, which not only enables childhood motor coordination but also greater coordination between emotions and planning in adulthood, as our brains are not developed in infancy or childhood. Physical development also includes puberty, sexual health, fertility, menopause, changes in our senses, and primary versus secondary aging. Healthy habits with nutrition and exercise are also important at every age and stage across the lifespan.
Cognitive Domain
If we watch and listen to infants and toddlers, we can’t help but wonder how they learn so much so fast, particularly when it comes to language development. Then, as we compare young children to those in middle childhood, there appear to be huge differences in their ability to think logically about the concrete world around them. Cognitive development includes mental processes, thinking, learning, and understanding, and it doesn’t stop in childhood. Adolescents develop the ability to think logically about the abstract world (and may like to debate matters with adults as they exercise their new cognitive skills!). Moral reasoning develops further, as does practical intelligence—wisdom may develop with experience over time. Memory abilities and different forms of intelligence tend to change with age. Brain development and the brain’s ability to change and compensate for losses are significant to cognitive functions across the lifespan, too.
Psychosocial Domain
Development in this domain involves what’s going on both psychologically and socially. Early on, the focus is on infants and caregivers, as temperament and attachment are significant. As the social world expands and the child grows psychologically, different types of play and interactions with other children and teachers become important. Psychosocial development involves emotions, personality, self-esteem, and relationships. Peers become more important for adolescents, who are exploring new roles and forming their own identities. Dating, romance, cohabitation, marriage, having children, and finding work or a career are all parts of the transition into adulthood. Psychosocial development continues across adulthood with similar (and some different) developmental issues of family, friends, parenting, romance, divorce, remarriage, blended families, caregiving for elders, becoming grandparents and great-grandparents, retirement, new careers, coping with losses, and death and dying.
As you may have already noticed, physical, cognitive, and psychosocial development are often interrelated, as with the example of brain development. We will be examining human development in these three domains in detail throughout the modules in this course as we learn about infancy/toddlerhood, early childhood, middle childhood, adolescence, young adulthood, middle adulthood, and late adulthood development, as well as death and dying.
Try It
Key Issues in Human Development
- Is the change smooth or uneven (continuous versus discontinuous)?
- Is this pattern of change the same for everyone, or are there different patterns of change (one course of development versus many courses)?
- How do genetics and environment interact to influence development (nature versus nurture)?
Is Development Continuous or Discontinuous?
Continuity versus Discontinuity: Is human development best characterized as a slow, gradual process, or is it best viewed as one of more abrupt change? The answer to that question often depends on which developmental theorist you ask and what topic is being studied.
- Continuous development (non-stage theories) theorists view development as a cumulative process, gradually improving on existing skills (Figure 2). With this type of development, there is a gradual change. Consider, for example, a child’s physical growth: adding inches to their height yearly. For instance, they would see the adult as not possessing new skills but as using more advanced skills that were already present in some form in the child. Brain development and environmental experiences contribute to the acquisition of more developed skills.
- Behavioral theorists, Vygotsky, and information processing theorists assume that development is a slower and more gradual process known as continuous development.
- Discontinuous development (stage theories) theorists believe that development takes place in unique stages and occurs at specific times or ages. They assume that developmental change occurs in distinct stages that are qualitatively different from each other and that unfold in a set, universal sequence. At each stage of development, children and adults have different qualities and characteristics. Thus, stage theorists assume development is discontinuous.
- Freud, Erikson, Piaget, and Kohlberg’s theories are called stage theories.
Is There One Course of Development or Many?
- Is development essentially the same, or universal, for all children (i.e., there is one course of development), or does development follow a different course for each child, depending on the child’s specific genetics and environment (i.e., there are many courses of development)?
- Do people across the world share more similarities or more differences in their development?
- How much do culture and genetics influence a child’s behavior?
Stage theories hold that the sequence of development is universal (Figure 3). For example, in cross-cultural studies of language development, children from around the world reach language milestones in a similar sequence (Gleitman & Newport, 1995). Infants in all cultures coo before they babble. They begin babbling at about the same age and utter their first word around 12 months old. Yet, we live in diverse contexts that have a unique effect on each of us. For example, researchers once believed that motor development followed one course for all children regardless of culture. However, childcare practices vary by culture, and different practices have been found to accelerate or inhibit the achievement of developmental milestones such as sitting, crawling, and walking (Karasik et al., 2010)
For instance, let’s look at the Aché society in Paraguay. They spend a significant amount of time foraging in forests. While foraging, Aché mothers carry their young children, rarely putting them down in order to protect them from getting hurt in the forest. Consequently, their children walk much later: They walk around 23–25 months old, in comparison to infants in Western cultures who begin to walk around 12 months old. However, as Aché children become older, they are allowed more freedom to move about, and by about age 9, their motor skills surpass those of U.S. children of the same age: Aché children are able to climb trees up to 25 feet tall, and use machetes to chop their way through the forest. (Kaplan & Dove, 1987). As you can see, our development is influenced by multiple contexts, so the timing of basic motor functions may vary across cultures. However, the functions are present in all societies.
How Do Nature and Nurture Influence Development?
Are we who we are because of nature (biology and genetics), or are we who we are because of nurture (our environment and culture)? This longstanding question is known in psychology as the nature versus nurture debate. It seeks to understand how our personalities and traits are the product of our genetic makeup and biological factors and how they are shaped by our environment, including our parents, peers, and culture. For instance, why do biological children sometimes act like their parents? Is it because of genetics or because of early childhood environment, and what has the child learned from their parents? What about children who are adopted—are they more like their biological families or more like their adoptive families? And how can siblings from the same family be so different?
We are all born with specific genetic traits inherited from our parents, such as eye color, height, and certain personality traits. Beyond our basic genotype, however, there is a deep interaction between our genes and our environment. Our unique experiences in our environment influence whether and how particular traits are expressed, and at the same time, our genes influence how we interact with our environment (Diamond, 2009; Lobo, 2008.) The modern study of epigenetics explores how environmental influences shape genetic expression. There is a reciprocal interaction between nature and nurture as they both shape who we become, but the debate continues as to the relative contributions of each. Developmentalists are also interested in differential susceptibility–how some people, either because of differences in genes or environmental experiences, are impacted differently by environmental events (Belsky & Pleuss, 2009). For example, why are some people relatively unscathed in the face of trauma while others are debilitated? We’ll explore these issues throughout the lifespan.
Try It
- continuous development: the idea that development is a progressive and cumulative process, gradually improving on existing skills
- discontinuous development: idea that development takes place in unique stages and occurs at specific times or ages
- nature: the influences of biology and genetics on behavior
- nurture: environmental, social, and cultural influences on behavior
Attributions
Human Growth and Development by Ryan Newton is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License,
Individual and Family Development, Health, and Well-being by Diana Lang, Nick Cone; Laura Overstreet, Stephanie Loalada; Suzanne Valentine-French, Martha Lally; Julie Lazzara, and Jamie Skow is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License,
Human Development by Human Development Teaching & Learning Group under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License,
References
Diamond, A. (2009). The interplay of biology and the environment broadly defined. Developmental Psychology, 45(1), 1–8.
Gleitman, L. R., & Newport, E. L. (1995). The invention of language by children: Environmental and biological influences on the acquisition of language. In L. R. Gleitman & M. Liberman (Eds.), An invitation to cognitive science, Vol. 1: Language. (2nd ed.) (pp. 1–24). MIT Press.
Karasik, L. B., Adolph, K. E., Tamis-LeMonda, C. S., & Bornstein, M. H. (2010). WEIRD Walking: Cross-cultural research on motor development. Behavioral & Brain Sciences, 33(2-3), 95–96.
Kaplan, H., & Dove, H. (1987). Infant development among the Aché of Eastern Paraguay. Developmental Psychology, 23, 190–198.
Lobo, I. (2008) Environmental influences on gene expression. Nature Education 1(1), 39.
