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The Nature-Nurture Debate

4. Gene-Environment Relationships

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About this Lecture


This fourth lecture explores how our genes and environment can relate, and combine, to create a final ‘output’ (phenotype). The example used to introduce this idea is height, noting that research shows that 60-80% of variation in people’s height can be attributed to genetic variation. One environmental factor involved is highlighted as diet, proposing that nutritional intake impacts the extent to which our genetic potential for height is expressed. Dr Kearney then outlines the key distinction between genotype and phenotype, explaining that our genotype can lay out a range of heights that we might achieve, while our phenotype is the observable characteristic of objectively how tall we actually are. The phenotype is where we see the role our environment has played on the expression of our genetic tendency for a particular characteristic. The lecture then introduces Caspi and colleagues’ 2003 study, implicating long and short alleles of the 5-HTT gene with depression outcomes in the face of negative life events. The last part of this lecture differentiates passive, active, and evocative correlations between genetic and environmental influences.


A genotype is the genetic composition of an individual organism as a whole, or at one specific position on a chromosome.

A phenotype is the observable characteristics of an individual, such as morphological or bio- chemical features and the presence or absence of a particular disease or condition.

A passive genotype-environment correlation refers to the association between the genotype that a child inherits from their parents and the environment in which that child is raised.

An active (or selective) genotype-environment correlation refers to the association between an individual's genetic propensities and the environmental niches that an individual selects.

An evocative (or reactive) genotype-environment correlation refers to the association between an individual's genetically influenced behaviour and others' reactions to that behaviour.


In this course, Dr Lydia Kearney (University of Kent) explores the nature ‘versus’ nurture debate in psychology. The first lecture prefaces the course by proposing the removal of ‘versus’, predicated on the origin of any human behaviour being too complicated to be explained by just one set of factors. The second lecture takes a deep dive into the nature side of this debate, introducing Mendelian genetics and explaining the concept of heritability. The third lecture explores the nurture side of this debate, outlining a timeline, from the ancient philosophers who proposed the tabula rasa, to modern research on environmental factors that impact aggressive tendencies. The fourth lecture brings in a modern perspective on the interactions between environmental and genetic factors when explaining phenotype expression. The fifth and final lecture uses Dr Kearney’s research specialism of social anxiety to exemplify how environmental and genetic factors, as well as their interactions, can predict the prevalence and experience of the condition.


Dr Lydia Kearney is a lecturer and Deputy School Director of Education in the School of Psychology at the University of Kent. Dr Kearney’s main areas of interest are social anxiety and experiences of mental imagery, particularly how the two interact and impact attention and interpretation biases. Dr Kearney’s recent research has included investigations of the links between imagery and rumination/emotion, incorporating mixed qualitative and quantitative methods.

Cite this Lecture

APA style

Kearney, L. (2021, December 13). The Nature-Nurture Debate - Gene-Environment Relationships [Video]. MASSOLIT.

MLA style

Kearney, Lydia. "The Nature-Nurture Debate – Gene-Environment Relationships." MASSOLIT, uploaded by MASSOLIT, 04 Jan 2022,

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