Niche picking

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Niche picking is a psychological theory that people choose environments that complement their heredity. For example, extroverts may deliberately engage with others like themselves. Niche picking is a component of gene-environment correlation. [1]

Contents

Scarr and McCartney's model

In 1983, psychology professors Sandra Scarr and Kathleen McCartney proposed that genes affect the environments individuals choose to interact with, and that phenotypes influence individuals’ exchanges with people, places, and situations. [2] The model states that genotypes can determine an individual's response to a certain environment, and that these genotype-environment pairs can affect human development. Scarr and McCartney, influenced by Robert Plomin's findings, recognized three types of gene-environment correlations. As humans develop, they enter each of these stages in succession, and each is more influential than the last.

Passive
During infancy, individuals' environments are provided by their parents. The rearing environment reflects the parents' genes, so it is genetically suitable for the child.
Evocative
Environments respond to individuals based on the genes they express (phenotype). Infants and adolescents evoke social and physical responses from their environments through this interaction. Experiences, and therefore development, are more influenced by evocation than by the passive environment. However, the influence of evocation declines over time.[ citation needed ]
Active
Individuals selectively attend to aspects of their environment that correlate to their specific genotypes and autonomously choose environments to interact with. Their selections are based on motivational, personality, and intellectual aspects of their genotype. Therefore, environmental interactions are person specific and can vary greatly. Since these environments are chosen rather than encountered, they have a greater effect on experience and development.[ citation needed ]

Role

Scarr and McCartney defined niche picking as a mechanism used to select environments suitable for one's genotype. Therefore, an individual’s temperament often affects the type of niche selected, since environment reflects one’s general disposition. [3]

An individual's niche can change over time, as explained in Emilie Snell-Rood's theory of behavioral plasticity and evolution. Snell-Rood argues that one element of developmental behavioral plasticity is the change in a gene’s expressed phenotype as a result of a change in environment. [4] Expressed behaviors reflect the environment one welcomes, and these behaviors change as a result of that environment. If an individual has encountered an environment before, their behavioral change can be attributed to learning, allowing the production of different responses. With respect to niche picking, this suggests that individuals' process of selecting environments evolves, as does their method of response and level of responsiveness.

Examples

The genotype-environment model states that as siblings and fraternal twins age, their phenotypes grow apart. This is due to their respective mastery of the passive, evocative, and active interactions. When the siblings are infants, the environments their parents provide are similar. But as they age and begin to evoke responses from their environments, the social and physical elements they encounter start to vary.[ citation needed ]

The personal characteristics that encourage environmental responses, such as appearance, personality, and intellect, are not the same between siblings and fraternal twins because of gene variations. Once siblings can actively interact with their environment and select environments they like, differences between their niches become clear. This process is evident in families where one child is outgoing and lively while the other is timid and cautious.

According to Frank Sulloway, a social researcher, most characteristic differences between siblings result from personality variation and non-shared environments, both of which are influenced by:

Together, these elements give siblings different evocative and active environmental experiences that reflect their individual niches.

In identical twins, this process is different. When siblings are the same age and have the same appearance, some people respond to them identically, despite their different personalities. Twins encounter the same social and physical influences from their environments, whether they have been reared separately or together. Often, this causes them to develop similar niches, [6] though it does not guarantee that they will.

Contemporary applications

Scarr and McCartney's model provides a framework for examining the role that children's genotypes play in determining environmental interactions. Two major topics associated with this research are public policies to promote children's education and the heritability of political beliefs.

Implications for policy makers

In a 1996 study, Scarr examined the implications of genotype-environment interaction for public policy, specifically in education. [7] She advised policy makers to be cautious when using programs such as Head Start to encourage intellectual development in children, arguing that genotype-environment interactions gave all children (except those raised in particularly abusive or neglectful homes) "good-enough opportunities" to develop without the aid of such programs.

Policy makers might expect to see a jump in children's intellectual abilities from programs such as Head Start, which are designed to introduce children to a school setting, create a stable environment, and further their cognitive talents. Scarr, however, suggests that they cannot fully recreate what intelligent parents and a nurturing environment provide. She instead advocates a varied and stimulating environment that lets children use various types of niche expression.

Scarr conducted an experiment in 1997 on the impact of out-of-home day care on children. [8] From this and previous studies, she concluded that the quality of day care had only small, temporary effects on intellectual development. She noted that for children from good homes, genotype-environment interaction usually provides most of the intellectual development they need. Parental and environmental support allows these children to explore the niches most suited to their intellectual desires and abilities.

These findings suggest that children from low-income families can benefit from programs that offer the same kind of support. Rather than a narrow environment that focuses on assimilating children into educational institutions, a stimulating environment would provide the most benefit to children who do not get adequate levels of genotype-environment interaction at home.

Related Research Articles

Heredity Passing of traits to offspring from the speciess parents or ancestor

Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. Through heredity, variations between individuals can accumulate and cause species to evolve by natural selection. The study of heredity in biology is genetics.

Phenotype Composite of the organisms observable characteristics or traits

In genetics, the phenotype is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book The Extended Phenotype suggested that one can regard bird nests and other built structures such as caddis-fly larva cases and beaver dams as "extended phenotypes".

Nature versus nurture Debate about heredity and environment as determinants of physical or mental development

Nature versus nurture is a long-standing debate in biology and society about the balance between two competing factors which determine fate: genetics (nature) and environment (nurture). The alliterative expression "nature and nurture" in English has been in use since at least the Elizabethan period and goes back to medieval French.

Genotype–phenotype distinction Distinction made in genetics

The genotype–phenotype distinction is drawn in genetics. "Genotype" is an organism's full hereditary information. "Phenotype" is an organism's actual observed properties, such as morphology, development, or behavior. This distinction is fundamental in the study of inheritance of traits and their evolution.

Heritability Estimation of effect of genetic variation on phenotypic variation of a trait

Heritability is a statistic used in the fields of breeding and genetics that estimates the degree of variation in a phenotypic trait in a population that is due to genetic variation between individuals in that population. The concept of heritability can be expressed in the form of the following question: "What is the proportion of the variation in a given trait within a population that is not explained by the environment or random chance?"

Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics and in content fields, from biology to psychology. Twin studies are part of the broader methodology used in behavior genetics, which uses all data that are genetically informative – siblings studies, adoption studies, pedigree, etc. These studies have been used to track traits ranging from personal behavior to the presentation of severe mental illnesses such as schizophrenia.

A maternal effect is a situation where the phenotype of an organism is determined not only by the environment it experiences and its genotype, but also by the environment and genotype of its mother. In genetics, maternal effects occur when an organism shows the phenotype expected from the genotype of the mother, irrespective of its own genotype, often due to the mother supplying messenger RNA or proteins to the egg. Maternal effects can also be caused by the maternal environment independent of genotype, sometimes controlling the size, sex, or behaviour of the offspring. These adaptive maternal effects lead to phenotypes of offspring that increase their fitness. Further, it introduces the concept of phenotypic plasticity, an important evolutionary concept. It has been proposed that maternal effects are important for the evolution of adaptive responses to environmental heterogeneity.

A sibling is a relative that shares at least one parent with the subject. A male sibling is a brother and a female sibling is a sister. A person with no siblings is an only child.

Human behaviour genetics

Human behaviour genetics is an interdisciplinary subfield of behaviour genetics that studies the role of genetic and environmental influences on human behaviour. Classically, human behavioural geneticists have studied the inheritance of behavioural traits. The field was originally focused on determining the importance of genetic influences on human behaviour. It has evolved to address more complex questions such as: how important are genetic and/or environmental influences on various human behavioural traits; to what extent do the same genetic and/or environmental influences impact the overlap between human behavioural traits; how do genetic and/or environmental influences on behaviour change across development; and what environmental factors moderate the importance of genetic effects on human behaviour. The field is interdisciplinary, and draws from genetics, psychology, and statistics. Most recently, the field has moved into the area of statistical genetics, with many behavioural geneticists also involved in efforts to identify the specific genes involved in human behaviour, and to understand how the effects associated with these genes changes across time, and in conjunction with the environment.

Gene–environment interaction Response to the same environmental variation differently by different genotypes

Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. A norm of reaction is a graph that shows the relationship between genes and environmental factors when phenotypic differences are continuous. They can help illustrate GxE interactions. When the norm of reaction is not parallel, as shown in the figure below, there is a gene by environment interaction. This indicates that each genotype responds to environmental variation in a different way. Environmental variation can be physical, chemical, biological, behavior patterns or life events.

Research on the heritability of IQ inquires into the proportion of variance in IQ that is attributable to genetic variation within a population. Heritability, in this sense, is a mathematical estimate of how much of a trait's variation within a population can be attributed to genetic variation between individuals in that population. There has been significant controversy in the academic community about the heritability of IQ since research on the issue began in the late nineteenth century. Intelligence in the normal range is a polygenic trait, meaning that it is influenced by more than one gene, and in the case of intelligence at least 500 genes. Further, explaining the similarity in IQ of closely related persons requires careful study because environmental factors may be correlated with genetic factors.

Personality development encompasses the dynamic construction and deconstruction of integrative characteristics that distinguish an individual in terms of interpersonal behavioral traits. Personality development is ever-changing and subject to contextual factors and life-altering experiences. Personality development is also dimensional in description and subjective in nature. That is, personality development can be seen as a continuum varying in degrees of intensity and change. It is subjective in nature because its conceptualization is rooted in social norms of expected behavior, self-expression, and personal growth.

David C. Rowe

David C. Rowe was an American psychology professor known for his work studying genetic and environmental influences on adolescent onset behaviors such as delinquency and smoking. His research into interaction between genetics and environment led to the discovery of the Scarr-Rowe effect.

Gene–environment correlation is said to occur when exposure to environmental conditions depends on an individual's genotype.

Neurogenetics

Neurogenetics studies the role of genetics in the development and function of the nervous system. It considers neural characteristics as phenotypes, and is mainly based on the observation that the nervous systems of individuals, even of those belonging to the same species, may not be identical. As the name implies, it draws aspects from both the studies of neuroscience and genetics, focusing in particular how the genetic code an organism carries affects its expressed traits. Mutations in this genetic sequence can have a wide range of effects on the quality of life of the individual. Neurological diseases, behavior and personality are all studied in the context of neurogenetics. The field of neurogenetics emerged in the mid to late 20th century with advances closely following advancements made in available technology. Currently, neurogenetics is the center of much research utilizing cutting edge techniques.

The differential susceptibility hypothesis proposed by Jay Belsky is another interpretation of psychological findings that are usually discussed according to the diathesis-stress model. Both models suggest that people's development and emotional affect are differentially susceptible to experiences or qualities of the environment. Where the Diathesis-stress model suggests a distinct and mostly negativity-sensitive group, Belsky describes a group that is sensitive to negative experiences but also to positive experiences. These models may be complementary, if some individuals are dually or uniquely positivity-sensitive, while other people are uniquely negativity-sensitive.

Behavioural genetics Study of genetic-environment interactions influencing behaviour

Behavioural genetics, also referred to as behaviour genetics, is a field of scientific research that uses genetic methods to investigate the nature and origins of individual differences in behaviour. While the name "behavioural genetics" connotes a focus on genetic influences, the field broadly investigates the extent to which genetic and environmental factors influence individual differences, and the development of research designs that can remove the confounding of genes and environment. Behavioural genetics was founded as a scientific discipline by Francis Galton in the late 19th century, only to be discredited through association with eugenics movements before and during World War II. In the latter half of the 20th century, the field saw renewed prominence with research on inheritance of behaviour and mental illness in humans, as well as research on genetically informative model organisms through selective breeding and crosses. In the late 20th and early 21st centuries, technological advances in molecular genetics made it possible to measure and modify the genome directly. This led to major advances in model organism research and in human studies, leading to new scientific discoveries.

Adoption studies are one of the classic research methods of behavioral genetics, used to estimate the degree to which variation in a trait is due to environmental and genetic influences. Adoption studies are typically used as well as twin studies when estimating heritability. The two types of adoption study designs are the Adoptee's study method, and the Adoptee's family method. The most powerful form of adoption studies compares pairs of genetically identical monozygotic identical (MZA) twins who are adopted into different families. Adoption studies have pinpointed that some traits are linked to genetics; for example, schizophrenia, IQ, and criminality. While genetics have a great impact in the lives of twins, other compound factors, such as age and environment, have a significant impact as well.

Behavioral plasticity refers to a change in an organism's behavior that results from exposure to stimuli, such as changing environmental conditions. Behavior can change more rapidly in response to changes in internal or external stimuli than is the case for most morphological traits and many physiological traits. As a result, when organisms are confronted by new conditions, behavioral changes often occur in advance of physiological or morphological changes. For instance, larval amphibians changed their antipredator behavior within an hour after a change in cues from predators, but morphological changes in body and tail shape in response to the same cues required a week to complete.

In biology, constructive development refers to the hypothesis that organisms shape their own developmental trajectory by constantly responding to, and causing, changes in both their internal state and their external environment. Constructive development can be contrasted with programmed development, the hypothesis that organisms develop according to a genetic program or blueprint. The constructivist perspective is found in philosophy, most notably developmental systems theory, and in the biological and social sciences, including developmental psychobiology and key themes of the extended evolutionary synthesis. Constructive development may be important to evolution because it enables organisms to produce functional phenotypes in response to genetic or environmental perturbation, and thereby contributes to adaptation and diversification.

References

  1. ↑ Jaffee, S. R., Jaffee, S. R., & Price, T. S. (2008). Genotype-environment correlations: Implications for determining the relationship between environmental exposures and psychiatric illness. Psychiatry (Abingdon, England), 7(12), 496-499.
  2. ↑ Scarr, S.; McCartney, K. (1983). "How People Make Their Own Environments: A Theory of Genotype → Environment Effects". Child Development. 54 (2): 424–435. CiteSeerX   10.1.1.473.7792 . doi:10.2307/1129703. JSTOR   1129703. PMID   6683622.
  3. ↑ Lemery, K. (2005). Temperament. In N. Salkind (Ed.), Encyclopedia of human development. (pp. 1256–1258). Thousand Oaks, CA: SAGE Publications, Inc. doi : 10.4135/9781412952484.n606
  4. ↑ Snell-Rood, E (2013). "An overview of the evolutionary causes and consequences of behavioral plasticity". Animal Behaviour. 85 (5): 1004–1011. doi:10.1016/j.anbehav.2012.12.031. S2CID   53188749.
  5. ↑ Sulloway, F. (2010). Why Siblings Are Like Darwin's Finches: Birth Order, Sibling Competition, and Adaptive Divergence within the Family. The evolution of personality and individual differences. New York: Oxford University Press.
  6. ↑ Plomin, R; DeFries, JC; Loehlin, JC (1977). "Genotype-environment interaction and correlation in the analysis of human behavior". Psychological Bulletin. 84 (2): 309–322. doi:10.1037/0033-2909.84.2.309. PMID   557211.
  7. ↑ Scarr, S (1996). "How people make their own environments: Implications for parents and policy makers". Psychology, Public Policy, and Law. 2 (2): 204–228. doi:10.1037/1076-8971.2.2.204.
  8. ↑ Scarr, S (1997). "Why child care has little impact on many children's developments". Current Directions in Psychological Science. 6 (5): 143–148. doi:10.1111/1467-8721.ep10772910. JSTOR   20182472. S2CID   143455774.
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