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Research Paper: How much of Brain and Behavior is Due to Heredity?
Introduction
In response to the question, “how much of brain and behavior is due to heredity?” This
paper will examine ways in which heredity impacts processes related to brain and behavior. The
brain and behavior are related to heredity due to genes influencing various brain structures and
functions resulting in differences in behavior. Heredity describes the genetic transmission of
traits from parents to their children through the passing on of the parents DNA. Genetic traits
may impact aspects of a person’s physical and psychological composition, including brain
structure, neurotransmitter function, and behavioral tendencies but one should not forget that
brain and behavior also includes actions and responses displayed by a person in response to
internal and external stimuli as well as emotional and social developments. In this paper, we will
explore the factors that influence brain and behavior, the role of heredity in brain and behavior
and the shaping of these traits, and the relationship between genetic and environmental
influences.
Understanding the contributions of heredity to brain and behavior has significant
implications for education and intervention. Recognizing the role of genetic dispositions in
cognitive abilities can inform personalized methods to education, allowing for designed
interventions to support individual students. Furthermore, understanding the genetic basis of
mental health concerns may guide the development of interventions and treatments.
Literature Review
First Point
The genetic code encoded in our DNA contains the instructions for the foundation and
organization of the brain, as well as the molecular machinery that inspires neural function. As a
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result, variants in the genetic code can have effects on brain structure and function, and by
extension, on behavior. Edward Drinker Cope made sizable contributions to the study of
evolution and inheritance. Cope was an advocate of neo-Lamarckian evolution, which theorized
that learned traits could be inherited by offspring. This viewpoint questioned the predominant
Darwinian view of natural selection as the primary method of evolution. Cope's emphasis on the
inheritance of acquired traits highlighted the importance of environmental influences and social
heredity. Cope’s work laid the foundation for more of an understanding of the connection
between social and biological heredity in evolutionary processes. Genetic factors contribute to
the development of the brain from the first stages of embryonic growth, guiding the formation of
neural progenitor cells, the migration of neurons, and the development of neural connections.
Studies using advanced imaging, such as magnetic resonance imaging (MRI), have provided
convincing evidence for the heritability of brain structure, signifying that genetic factors explain
a substantial percentage of individual differences in brain morphology, such as the size and
shape of various brain regions. (Ceccarelli, 2019).
Intelligence and behaviors are shaped by a host of social factors, including access to
education, socioeconomic status, and social expectations. Gaps in educational opportunities can
influence intellectual development and academic achievement. Other contributing factors include
but are not limited to poverty and discrimination. Poverty and discrimination can impact a
person’s behaviors, mental health, and emotional well-being (Graves & Goodman, 2022).
Second Point
Mutations or variations in genes can lead to neurodevelopmental disorders, highlighting
the substantial effect of heredity on brain structure, function, and behavior. Heredity plays a
leading role in shaping the structure and function of the brain. The human brain is an intricate
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organ composed of neurons and glial cells. Its development and function are noted to be
intricately correlated to genetic factors. Advances in molecular genetics have acknowledged
genes associated with cognitive functions, shedding light on the genetic foundation of intellect
and other cognitive traits. Studies using twin and family-based outlines have presented evidence
for the heritability of cognitive and behavioral traits, including intelligence and personality
(Pizzorusso & Tognini, 2020). Furthermore, studies utilizing twin and adoption designs have
been helpful in assessing the heritability of various behavioral traits. By comparing the
similarities of identical twins, who share 100% of DNA with those of fraternal twins, who share,
on average, 50% of their DNA, researchers can approximate the genetic influence on a particular
trait. These studies have concluded that genetic factors play a sizable role in behavioral
tendencies (Misiewicz et al, 2019).
Personality traits, such as extraversion, introversion, psychoneurosis, and
conscientiousness, have a genetic element. Research has estimated the heritability of personality
traits to be around 40-60%, suggesting that genetic factors play a role in shaping an individual's
personality and behaviors. In addition, research has recognized genes that are linked to specific
personality traits, providing evidence of the genetic foundations of personality.
In addition to heredity, the degree of social interactions within a species has been
suggested to influence brain size. The developmental constraints hypothesis posits that
limitations during early development, such as constraints on the availability of resources, may
impact brain size which in turn may have an effect on behavior (Hardie and Cooney, 2023).
The nature versus nurture debate revolves around the contributions of genetics (nature)
and environment (nurture) to the development of human traits, including cognitive abilities,
personality, and behavior. This debate has been framed as a dichotomy, with supporters for each
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side. However, research has stressed the interaction and correlation of genetic and environmental
factors in shaping human development.
Third Point
It is critical to understand that the relationship between heredity and behavior is not one
sided, and environmental influences may play a fundamental role in shaping a person's
psychological structure. The interaction between genetic tendencies and environmental
experiences has been known to contribute to the development of behavioral traits, and research
in the field of behavioral genetics has begun to focus on explaining the mechanisms by which
genetic and environmental factors interact to influence behavior. Research utilizing
neuroimaging techniques has uncovered how genetic factors influence the irregularity in brain
structure and function observed across people. For instance, studies researching the heritability
of brain volume, cortical thickness, and connectivity patterns have discovered genetic influences
on these neuroanatomical features. Moreover, studies into the genetic basis of cognitive abilities,
such as, but not limited to, language processing and mathematical reasoning, have emphasized
the role of genetic variation in shaping the functional organization of the brain (Naqvi et al,
2021).
The interplay between gene expression, neural activity, and behavioral responses in the
context of social interactions and dominance contests represents a fascinating area of study It is
plausible to hypothesize that the heritability of brain function contributes to the observed
variations in social interactions and dominance outcomes. By examining the genetic markers
associated with social behavior and dominance, researchers can unravel the intricate web of
interactions that shape the behavior (Uy et al, 2021).
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Biblical Review Integration
The Bible is a great resource for how heredity influences brain and behavior. From a
Biblical worldview, the concept of heredity can be traced back to the creation of humanity in the
book of Genesis, where God's design for man is discussed. The idea of being fearfully and
wonderfully made (Psalm 139:14. King James Version) suggests that the details of human
biology, including brain development, are part of God's design. This viewpoint highlights the
importance of heredity in shaping the human brain and behavior. The concept of genetic
influences on behavior raises questions about the nature of sin and human immorality. The
doctrine of original sin, stemming from the fall of Adam and Eve in the Garden of Eden,
acknowledges the inherited sinful nature of humanity as a result of Adam and Eve's
disobedience. The children of Adam and Eve, Cain and Able, are a prime example of how sinful
or “bad” behavior may be inherited. After the fall of Adam and Eve, came the death of Able by
the hands of his brother, Cain. This view transects with the understanding of genetic
predispositions to certain behaviors, triggering reflection on the consequences for moral
responsibility and the need for redemption from sin. The relationship between genes and
environment echoes the concept of sanctification and the transformative power of God's grace,
mercy, and love. The idea that people are shaped by both inherent tendencies and external
influences aligns with the Bible and the importance of nurturing one's faith. According to the
Bible, behavior can be shaped by example in both a negative and a positive perspective. An
example of the negative is that of the children of Adam and Eve. Through the positive, the Bible
tells us to train a child in the way it should go, and the child will not depart from it (Proverbs
22:6, KJV). This scripture gives peace in knowing that when a child is shown positive behaviors,
a child will then heed that example and exude positive behavior. This view highlights the impact
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of environmental factors influencing human behavior while recognizing the role of heredity in
brain development. The magnitude to which brain and behavior are shaped by heredity is a
complex issue that incorporates scientific, theological, and ethical proportions. From a biblical
worldview perspective, the interplay between genetics, environment, and moral factors offers an
outline for understanding human experience. While heredity shapes aspects of brain development
and behavioral tendencies, the Bible stresses the possibility for spiritual change and the
redemption power of God's grace and mercy. By integrating scientific perceptions with biblical
teachings, an understanding of the relationship between heredity, brain, and behavior can be
reached.
Conclusion
In conclusion, the question of how much of brain and behavior are due to heredity is a
complex one, with a wealth of evidence from genetics, neuroscience, and psychology. The
exploration of heredity's influence on brain and behavior raises important ethical and social
considerations. Genetic factors play a substantial role in shaping brain development, cognitive
abilities, personality traits, and vulnerability to mental and emotional health concerns, with
heritability estimations signifying that genetic factors explain a considerable proportion of the
variability in these traits. However, it is imperative to identify the relationship between genes and
the environment in influencing human behavior, highlighting the need for a complete
understanding of genetic and environmental factors on the brain and behavior. It is vital to
approach discussions about brain and behavior with consideration for the ethical implications of
genetic research in the context of brain and behavior.
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References
Ceccarelli, D. (2019). Between Social and Biological Heredity: Cope and Baldwin on Evolution,
Inheritance, and Mind. Journal of the History of Biology, 52(1), 161–194.
http://www.jstor.org/stable/45216509
Dong, Y., Weng, J., Zhu, Y., Sun, D., He, W., Chen, Q., Cheng, J., Zhu, Y., & Jiang, Y. (2023).
Transcriptomic profiling of the developing brain revealed cell-type and brain-region
specificity in a mouse model of prenatal stress. BMC Genomics, 24(1), 86-86.
https://doi.org/10.1186/s12864-023-09186-8
Graves, J. L., & Goodman, A. H. (2022). Intelligence, Brains, and Behaviors. In Racism, Not
Race: Answers to Frequently Asked Questions (pp. 134–157). Columbia University Press.
http://www.jstor.org/stable/10.7312/grav20066.12
Hardie, J. L., & Cooney, C. R. (2023). Sociality, ecology, and developmental constraints predict
variation in brain size across birds. Journal of Evolutionary Biology, 36(1), 144-155.
https://doi.org/10.1111/jeb.14117
King James Version Bible (1611/2015) Divine Name Publishers
Misiewicz, Z., Iurato, S., Kulesskaya, N., Salminen, L., Rodrigues, L., Maccarrone, G., Martins,
J., Czamara, D., Laine, M. A., Sokolowska, E., Trontti, K., Rewerts, C., Novak, B., Volk,
N., Park, D. I., Jokitalo, E., Paulin, L., Auvinen, P., Voikar, V., . . . Hovatta, I. (2019).
Multi-omics analysis identifies mitochondrial pathways associated with anxiety-related
behavior. PLoS Genetics, 15(9), e1008358-e1008358.
https://doi.org/10.1371/journal.pgen.1008358
Pizzorusso, T., & Tognini, P. (2020). Interplay between metabolism, nutrition and epigenetics in
shaping brain DNA methylation, neural function and behavior. Genes, 11(7), 742.
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https://doi.org/10.3390/genes11070742
Naqvi, S., Sleyp, Y., Hoskens, H. et al. Shared heritability of human face and brain shape. Nat
Genet 53, 830–839 (2021). https://doi.org/10.1038/s41588-021-00827-w
Uy, F. M. K., Jernigan, C. M., Zaba, N. C., Mehrotra, E., Miller, S. E., & Sheehan, M. J. (2021).
Dynamic neurogenomic responses to social interactions and dominance outcomes in
female paper wasps. PLoS Genetics, 17(9), e1009474-e1009474.
https://doi.org/10.1371/journal.pgen.1009474
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