Niche picking

Niche picking is a psychological theory that suggests that children and adults choose environments that complement their heredity. For example, people who are extroverted by nature may deliberately engage socially, especially with other extroverts like themselves. Niche picking is part of the larger subject of gene-environment correlations. The three types of genotype-environment correlation are passive, evocative (reactive) and active, (or selective).^[1]

Scarr and McCartney's model

In 1983, Sandra Scarr and Kathleen McCartney proposed their theory of genotype-environment effects.^[2] The model describes how an individual’s genes influence the environments they interact with and how variable phenotypes influence an individual’s exchanges with people, places and situations. They argue that genotypes elicit varying levels and forms of responses that an individual has to an environment and the genotype-environmental pairs that influence human development. Influenced by Robert Plomin's findings, Scarr and McCartney recognize three types of genes, which are environmental interaction processes that take place in human development:^[3]

Passive

During infancy, parents provide the environment for the individual. This rearing environment reflects the nature of the parental genes, so it is genetically suitable for the child.

Evocative

The environment responds to the individual because of the genes they express (phenotype). Infants and adolescents evoke social and physical responses from the environment through this genotype→environment interaction. Experiences and therefore development are more influenced by evocation than by the passive environment but the influence of evocation declines over time.

Active

Individuals selectively attend to aspects of their environment that correlate to their specific genotypes and choose environments to interact with. Their selections correlate to motivational, personality and intellectual aspects of their genotype. Environmental interactions are therefore person specific and can vary greatly or very little. Experience and development are influenced more by the active process since environments are chosen rather than encountered.

As humans develop they enter each genotype-environment stage, each being more influential on development than the last. In the final genotype→environment state; 'Active', the individual is autonomous in encountering and responding to elements around them. Scarr and McCartney suggest that the functioning of this type of interaction and the autonomous tendencies themselves depend on niche-picking for the selection of environments.

Role of Niche-Picking

Scarr and McCartney identify niche-picking as a tool used in the selecting of environments found suitable for one's genotype. Therefore an individual’s temperament often affects the type of niche selected, since environment reflects one’s general disposition.^[4] The niche-picking process is different from selective attention, as it is more than discriminating among responses; it is the selection of the desired environment, which guarantees a response.

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.^[5] Expressed behaviors reflect the environment one welcomes and they change as a result of that environment. Should the individual have encountered the environment before, their behavioral change can be attributed to learning—experience which leads to development, which encourages learning, allowing the production of different responses. With respect to niche-picking, this suggests that the process of selecting environments evolves throughout an individual’s continuous process of development, as does their method of response and level of responsiveness.

Examples of Niche-Picking

The genotype→environment model states that as siblings and fraternal twins age, their phenotypes grow apart due to their respective mastery of the passive, evocative and active interactions, which then play a role in differentiating their niches. When the siblings are infants the environments their parents provide are similar, since parents' rearing reflects their genes. As the siblings age and begin to evoke responses from their environments the social and physical elements they encounter vary.

The personal characteristics that encourage environmental responses, such as appearance, personality and intellect are not the same between different siblings and fraternal twins because of gene variations. As a result of gene variation, environmental preferences emerge that reflect both their similarities and differences. 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 and the other is more timid and cautious.

Frank Sulloway, a social researcher, explains niche variations between siblings by describing the causes and results of sibling differences. The majority of characteristic differences between siblings result from personality variation and the non-shared environment, both of which are influenced by:

• parental investment
• the tendency for siblings to differentiate themselves from each other, often by assuming opposite dispositions
• by birth order, personality and gender roles.^[6]

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

In identical twins this process is different. When twins are the same age and have the same appearance, though personality differences may be present, people respond to them identically. Twins encounter the same social and physical influences from their environments, whether they have been reared separately or together, which often causes them to develop similar niches.^[7] The fate of identical twins is not necessarily similar, rather this shared genotype→environment interaction produces a tendency for them to adopt the same niche but does not guarantee that they will.

Contemporary Applications

Scarr and McCartney’s model provides a framework for examining the role children’s genotypes might play in determining later environmental interactions. Two major fields that this research has been associated with are creation of 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 that the genotype-environment interaction could have for the creation of public policy, specifically in education.^[8] In the study, Scarr advises policy-makers to show caution when using programs such as Head Start to encourage intellectual development in children. Scarr holds that the genotype-environment interactions explain why all children (except those raised in particularly abusive or neglectful homes) have “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 introduce children to a school setting and work to create a stable environment and further their cognitive talents. Scarr instead suggests that they merely provide the appearance of giving children more opportunities.

These programs attempt to provide more intellectually challenging environments for less able children but cannot fully re-create what intelligent parents and a nurturing environment can provide, which produces unrealistic expectations for their success. Scarr instead advocates a varied and stimulating program environment that lets children use various types of niche expression for optimal development.

Scarr conducted an experiment in 1997 on the impact of out-of-home daycare on children.^[9] From this and previous studies, Scarr concluded that the quality of daycare had only small, temporary effects on children’s intellectual development. Scarr noted that children from good homes usually have the genotype-environment interaction that provides the greater portion of the intellectual development they need. Parental and environmental support among these children allows the opportunity to explore the niche most suited to their intellectual desires and abilities.

These findings suggest that children from low-income families, who may not have these opportunities at home can benefit from early start programs that offer the same kind of support. The true goal of childcare improvement should be to provide a wide-ranging and stimulating learning environment for children who may not have access to one. Instead of a more narrow environment, which would focus on assimilating children into educational institutions, a stimulating environment provides the most benefit to children who do not get adequate levels of genotype-environment interaction in their homes.

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