Hereditary and Environmental Factors (VCE SSCE Psychology): Revision Notes
Hereditary and Environmental Factors
Introduction to psychological development
Understanding psychological development is essential for explaining how humans learn, mature and adapt throughout their lives. By examining the changes that occur at each stage of the lifespan and the factors influencing them, psychologists can explain our thoughts, feelings and behaviours.
Psychological development refers to the changes in an individual's social, emotional and cognitive abilities from infancy through to old age.
When psychologists understand typical developmental patterns across different life stages, they can identify what constitutes 'normal' or 'typical' development and recognise when development is 'atypical'.
Understanding what constitutes typical development provides psychologists with a baseline for comparison. This allows them to identify when an individual's development may be following an atypical pattern, which can inform early intervention strategies and support services.
Three main areas of psychological development
Psychological development occurs across three interconnected domains, meaning that changes in one area often influence development in the others:
Social development
Social development involves learning how to interact with others effectively. This includes:
- Learning to share and take turns during play
- Developing and maintaining ongoing friendships
- Understanding social rules and expectations
- Building relationships with peers and adults
Emotional development
Emotional development encompasses the ability to understand and manage emotions. This includes:
- Identifying and recognising different emotions in oneself and others
- Self-regulating emotions appropriately
- Expressing emotions that are suitable for different situations
- Developing emotional resilience
Cognitive development
Cognitive development refers to the growth of mental processes and intellectual abilities. This includes:
- Being able to sort objects by characteristics such as shape and colour
- Performing increasingly complex mathematical calculations
- Developing vocabulary and language skills
- Problem-solving and critical thinking abilities
These three areas of development are influenced by complex and interacting factors, which are categorised as either hereditary or environmental factors.
Hereditary factors
What are hereditary factors?
Many characteristics that make us unique individuals are determined before birth at conception, when sperm meets egg. Hereditary factors are the biological influences on development that result from genetic information passed from biological parents to their offspring.
Key genetic concepts
Genes are the basic units of heredity or inheritance. They contain genetic information and form sections of DNA. At conception, genetic material from each biological parent combines to form a unique set of genes.
Heredity (or inheritance) is the passing on of genes or genetic information from parents to their offspring.
Understanding Genotype and Phenotype
Genotype refers to all the genes that a person has inherited from their biological parents. This represents the complete genetic blueprint inherited at conception.
Phenotype refers to how a person's genes are actually expressed. This is the observable outcome of the interaction between genotype and environment.
Think of it this way: your genotype is your genetic recipe, whilst your phenotype is the final dish that results when that recipe interacts with environmental ingredients.
Genetically determined characteristics
Hereditary factors determine or influence various characteristics, including:
Fixed characteristics (remain constant throughout life):
- Eye colour
- Blood type
- Bone structure
- Facial features such as nose shape
Influenced characteristics (affected by genes but not entirely determined):
- Aspects of personality
- Likelihood of developing certain mental disorders
- Level of intelligence
- Physical abilities
Whilst some characteristics are completely fixed by our genes (like blood type), many others are only influenced by heredity. These influenced characteristics can be significantly shaped by environmental factors, meaning our genes provide a range of possibilities rather than a fixed outcome.
The twin study example
Real-World Example: The Bordier-Futerman Twin Study
The case of identical twins Anaïs Bordier and Samantha Futerman illustrates the complex relationship between hereditary and environmental factors. Born in South Korea and separated at birth, they were adopted by families on opposite sides of the world. They discovered each other through social media in 2012.
Despite having identical DNA (identical genotype), research conducted at California State University found both similarities and differences:
Similarities (likely hereditary):
- Similar heights and weights
- Same age of first menstruation
- Both disliked cooked vegetables
- Feared being touched by shower curtains
- Required 10 hours of sleep nightly
- Took naps when stressed
Differences (likely environmental):
- Anaïs was less extroverted
- Anaïs had lower self-esteem
- 17-point difference in IQ scores
These differences, despite identical genetic material, demonstrate that environmental factors influence how genes are expressed.
The genotype-phenotype relationship
Think of genotype as a blueprint for building a house. The same architectural plan can result in houses with similar structures, but different surface finishes, furniture and furnishings make each unique.
Similarly, whilst a child's genotype represents a developmental plan, environmental factors influence how genes are expressed, determining the final phenotype. This is why identical twins with the same genotype can have different phenotypes.
Environmental factors
Environmental factors are the different external influences within a person's environment that can affect their development. The way a child is raised, their experiences, relationships, education and access to resources all play substantial roles in shaping development.
Types of environmental factors
Environmental influences can be categorised into five main types:
1. Physical environment
The physical surroundings in which a child develops, including:
- Exposure to pollutants
- Disease exposure
- Extreme temperatures
- Nutrition and food security
- Risk of accidents or injuries
- Quality of living conditions
- Access to clean water
Impact on development: The living environment affects all aspects of development. Poor physical environments may increase exposure to disease and pollution whilst reducing access to basic resources. If a child has many siblings, caregiver attention may be divided amongst all children, affecting the quality of individual care.
2. Sociocultural environment
The social and cultural context in which development occurs, including:
- Values and beliefs
- Religious practices and teachings
- Social norms and expectations
- Cultural traditions
- Income and socioeconomic status
Impact on development: Greater income or wealth affects a child's access to resources, including basic needs (shelter, clothing, food), quality education, extracurricular activities (such as music lessons), travel opportunities, and the amount of time parents can spend with the child versus working.
3. Prenatal environment
Factors affecting the developing foetus before birth, including:
- Mother's nutrition during pregnancy
- Alcohol consumption during pregnancy
- Drug use during pregnancy
- Exposure to toxins or harmful substances
Impact on development: Alcohol consumption at any stage of pregnancy can damage the developing baby's brain, body and organs, potentially leading to Foetal Alcohol Spectrum Disorder (FASD). It also increases risks of miscarriage, stillbirth, and premature or underweight births.
There is no safe amount of alcohol consumption during pregnancy.
4. Learning environment
The educational and stimulating experiences provided, including:
- Sensory input and stimulation
- Opportunities for play
- Quality of education
- Access to learning resources
Impact on development: Children are born ready to learn and depend on caregivers to help develop skills for independence and success. Brain growth and development relies heavily on sensory stimulation from environmental experiences with people and the world.
5. Emotional environment
The quality of emotional relationships and support, including:
- Attachment to caregivers
- Close interpersonal relationships
- Emotional comfort and security
- Quality of parent-child bonding
Impact on development: Bonding within a family helps nurture and protect a child physically and emotionally. Parents who spend quality time with their child and provide comfort and safety create secure attachment. The quality of the caregiver-child bond influences development, particularly social and emotional aspects.
The interactive nature of hereditary and environmental factors
Most developmental psychologists today examine the interrelationship between hereditary and environmental influences using the biopsychosocial approach. This approach considers psychological development as being influenced by interacting biological, psychological and social factors.
How environment influences gene expression
Whilst we all inherit specific genes from our biological parents, there is complex interaction between these genes and our environment. The unique experiences we have can influence how our genes are expressed (our phenotype).
Worked Example: Intelligence Development
The combination of genes we receive is associated with our intelligence level, but this is not fixed. Environmental factors influence the expression of these genes and therefore how intelligent we become:
Positive environmental factors that enhance intelligence:
- Encouragement and support
- Access to quality education
- Opportunities for achievement and extension
- Intellectual stimulation
Scenario 1: Even if biological parents are highly intelligent, lacking positive environmental factors may result in a child not reaching their genetic potential.
Scenario 2: Conversely, if biological parents are not highly intelligent but the child is exposed to numerous positive environmental factors, they can develop greater intelligence than might otherwise have been the case.
How genes influence environmental interaction
The relationship works bidirectionally - genes can also influence how we interact with our environment.
Worked Example: Personality Traits and Social Interaction
A person with a genetic disposition towards shyness or introversion may be more likely to:
- Spend more time alone
- Feel less confident in social situations
- Have fewer close friendships
- Receive fewer positive social responses from peers
By contrast, a person genetically disposed towards extroversion may:
- Seek out more social connections
- Develop more close friendships
- Feel more confident in social situations
- Receive more positive social reinforcement
These environmental experiences can reinforce individuals' pre-existing biological traits, creating a feedback loop between heredity and environment.
The challenge of determining influence
It is difficult for psychologists to determine the precise weight of influence that hereditary and environmental factors have on development. Both are constantly interacting and influencing each other throughout the lifespan. Most characteristics and abilities result from the complex interplay between our genetic blueprint and our lived experiences.
Key Points to Remember:
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Psychological development encompasses changes in social, emotional and cognitive abilities from infancy through to old age
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Hereditary factors are biological influences from genes passed from parents to offspring at conception, whilst environmental factors are external influences from a person's surroundings
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Genotype is the complete set of inherited genes; phenotype is how those genes are actually expressed
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Environmental factors include physical, sociocultural, prenatal, learning and emotional influences
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Hereditary and environmental factors interact bidirectionally - genes influence how we interact with our environment, and environment influences how genes are expressed
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Most developmental psychologists use the biopsychosocial approach to understand the complex interplay between biological, psychological and social factors in development