Читать книгу Infants and Children in Context - Tara L. Kuther - Страница 60

What motivates parents of most species to care for their young? Some researchers argue that caregiving behaviors have an evolutionary basis. Ethology is the scientific study of the evolutionary basis of behavior (Bateson, 2015). In 1859, Charles Darwin proposed his theory of evolution, explaining that all species adapt and evolve over time. Specifically, traits that enable a species to adapt, thrive, and mate tend to be passed to succeeding generations because they improve the likelihood of the individual and species’ survival. Several early theorists applied the concepts of evolution to behavior. Konrad Lorenz and Niko Tinbergen, two European zoologists, observed animal species in their natural environments and noticed patterns of behavior that appeared to be inborn, emerged early in life, and ensured the animals’ survival. For example, shortly after birth, goslings imprint to their mother, meaning that they bond to her and follow her. Imprinting aids the goslings’ survival because it ensures that they stay close to their mother, get fed, and remain protected. In order for imprinting to occur, the mother goose must be present immediately after the goslings hatch; mothers instinctively stay close to the nest so that their young can imprint (Lorenz, 1952).

According to John Bowlby (1969), humans also display biologically preprogrammed behaviors that have survival value and promote development. For example, caregivers naturally respond to infants’ cues. Crying, smiling, and grasping are inborn ways that infants get attention from caregivers, bring caregivers into physical contact, and ensure that they will be safe and cared for. Such behaviors have adaptive significance because they meet infants’ needs and promote the formation of bonds with caregivers, ensuring that the caregivers will feel a strong desire and obligation to care for them (Bowlby, 1973). In this way, innate biological drives and behaviors work together with experience to influence adaptation and ultimately an individual’s survival.

Another theory, evolutionary developmental theory, applies principles of evolution and scientific knowledge about the interactive influence of genetic and environmental mechanisms to understand the changes people undergo throughout their lives (Bjorklund, 2018a; Witherington & Lickliter, 2016). You may have wondered, for example, whether you—your abilities, personality, and competencies—result from your genes or from the physical and social environment in which you were raised. Evolutionary developmental scientists explain that this is the wrong question to ask. From an evolutionary development perspective, genes and context interact in an ever-changing way such that it is impossible to isolate the contributions of each to development (Witherington & Lickliter, 2016). While all of our traits and characteristics are influenced by genes, contextual factors influence the expression of genetic instructions. This process is known as epigenetics (Moore, 2017). The term epigenetics literally means “above the gene.” Individuals are influenced by both genetic and contextual factors; however, as shown in Figure 1.5, some contextual factors can determine whether and how genetic capacities are expressed or shown.

Description

Figure 1.5 Interaction of Genetic and Environmental Factors

Development is influenced by the dynamic interplay of genetic and environmental factors. Genetic predispositions may influence how we experience environmental factors, and environmental factors may influence how genes are expressed.

Source:, Picker (2005).

As an example, contextual factors such as gravity, light, temperature, and moisture influence how genes are expressed and therefore how individuals develop (Meaney, 2017). For instance, in some reptiles such as crocodiles, sex is determined by the temperature in which the organism develops. Eggs incubated at one range of temperatures produce male crocodiles and at another temperature produce female crocodiles (Pezaro, Doody, & Thompson, 2017).

According to evolutionary developmental theory, genetic factors and biological predispositions interact with the physical and social environment to influence development, and Darwinian natural selection determines what genes and traits are passed on to the next generation (Bjorklund, 2018a; Witherington & Lickliter, 2016). Children are viewed as active in their development, influencing their contexts, responding to the demands for adaptation posed by their contexts, and constantly interacting with and adapting to the world around them. The relevance of both biological and contextual factors to human development is indisputable, and most developmental scientists appreciate the contributions of evolutionary developmental theory (DelGiudice, 2018; Frankenhuis & Tiokhin, 2018; Legare, Clegg, & Wen, 2018). The ways in which biology and context interact and their influence on development change over the course of the lifetime, as we will discuss throughout this book.