Spotlight on Genetics, Environment and Individual Differences

Selecting an assistance animal involves far more than choosing the “right” breed. While genetics provide the foundation for an animal’s physical characteristics and behavioural predispositions, every animal develops through a complex interaction between its genes, prenatal development, early experiences, learning, health and environment.

Understanding this interaction helps explain why two animals of the same breed—or even two littermates—can develop into very different individuals. For occupational therapists and assistance animal professionals, recognising these influences supports evidence-informed selection while avoiding assumptions based solely on breed or pedigree.

Nature and Nurture Work Together

One of the oldest debates in biology and psychology asks whether behaviour is determined by nature (genetics) or nurture (environment). Modern science recognises that the answer is both.

Genetics influence characteristics such as:

• temperament
• learning ability
• emotional sensitivity
• resilience
• physical structure
• coat type
• disease risk
• behavioural predispositions

However, genetics alone do not determine behaviour. Throughout life, an animal’s experiences influence how these inherited characteristics are expressed.

Environmental influences include:

• prenatal development
• maternal health and stress
• early nutrition
• neonatal handling
• socialisation
• training methods
• exposure to new environments
• health and pain
• ongoing learning experiences

Rather than acting independently, genetics and environment continuously interact throughout an animal’s life.

Genetics Load the Gun—Environment Pulls the Trigger

A useful way of understanding this relationship is the saying:

“Genetics load the gun; environment pulls the trigger.”

This analogy illustrates that genetics create a range of possible outcomes, but life experiences influence which of those outcomes are ultimately expressed.

For example, a puppy may inherit a naturally confident temperament, but poor socialisation or repeated frightening experiences may result in fearfulness later in life. Conversely, a puppy with mild environmental sensitivity may develop into a confident, resilient adult when provided with appropriate socialisation, positive learning experiences and supportive management.

Importantly, neither genetics nor environment can completely override the other. Good training cannot entirely compensate for poor genetics, and excellent genetics cannot completely protect an animal from the effects of neglect, chronic stress or inadequate socialisation.

Successful assistance animal selection therefore requires consideration of both inherited characteristics and developmental experiences.

Prenatal Development Matters

Development begins long before a puppy is born.

The health and wellbeing of the mother during pregnancy influence the developing puppies through nutrition, hormones and the prenatal environment.

Research has demonstrated that excessive maternal stress, poor nutrition, illness and inadequate husbandry may influence neurological development and later behaviour.

Responsible breeders therefore focus not only on producing genetically healthy puppies but also on supporting the physical and behavioural wellbeing of breeding animals throughout pregnancy.

The Importance of Early Socialisation

The first weeks and months of life represent a critical period for behavioural development.

Appropriate early socialisation helps puppies learn that the world is generally safe and predictable while developing confidence around:

• people
• children
• other animals
• different environments
• household noises
• vehicles
• veterinary handling
• grooming
• novel objects

Effective socialisation does not involve exposing puppies to as many situations as possible regardless of their emotional response. Instead, it involves carefully managed, positive experiences that build confidence without overwhelming the animal.

Poorly managed socialisation can be as detrimental as insufficient socialisation.

Learning Never Stops

Behaviour continues to develop throughout life.

Each interaction with the environment provides new learning opportunities that may strengthen or weaken behavioural responses.

Positive reinforcement, consistent routines, predictable environments and appropriate enrichment all contribute to emotional stability and behavioural resilience.

Conversely, chronic stress, pain, inconsistent handling or frightening experiences may negatively influence behaviour regardless of the animal’s genetic potential.

Assistance animals therefore require ongoing learning and support throughout their working lives—not simply during puppyhood.

Every Individual Is Different

Even within the same litter, puppies differ considerably.

One puppy may naturally investigate new environments with confidence, another may be cautious, while a third may display greater social engagement or problem-solving ability.

These differences are normal.

Selecting an assistance animal therefore requires assessment of the individual, rather than assuming all puppies from a successful breeding line will develop similarly.

Likewise, an animal that appears quieter or more energetic than its littermates is not necessarily better or worse—it may simply be better suited to a different role.

Avoiding Genetic Determinism

One common misconception is that genetics determine everything.

While inherited characteristics strongly influence behaviour, they do not guarantee success or failure.

For example:

• Not every Labrador Retriever becomes a successful assistance dog.
• Not every Border Collie is unsuitable for public access work.
• Not every rescue dog has behavioural problems.
• Not every purpose-bred puppy will complete assistance training.

Similarly, dogs should not be dismissed because of isolated behavioural events. Behaviour should always be interpreted within the context of the animal’s health, development, learning history and current environment.

Professionals should avoid both genetic determinism (“it’s all in the genes”) and environmental determinism (“it’s all about how they’re raised”). Evidence supports a balanced understanding that both contribute to behavioural development.

Implications for Assistance Animal Selection

Recognising the interaction between genetics and environment explains why assistance animal selection is a gradual process rather than a single decision.

Selection considers:

• inherited temperament
• health and genetic background
• prenatal influences
• early development
• behavioural assessment
• learning history
• environmental resilience
• current behaviour

Each provides important information, but none should be interpreted in isolation.

This is also why reputable assistance animal organisations continue assessing dogs throughout their development. Behaviour changes as animals mature, and selection decisions should be based on multiple observations over time rather than a single assessment.

Practice Examples

WAFA assessed two Golden Retriever puppies from the same litter as potential assistance dog prospects. Both puppies came from health-tested parents and had experienced excellent early socialisation. During temperament assessments, one puppy consistently demonstrated calm confidence, rapid recovery after unexpected noises and a strong focus on people. The second puppy was equally healthy but remained more environmentally cautious and required additional time to investigate unfamiliar situations. Neither puppy was considered “better”; instead, WAFA recognised that their differing temperaments made them suitable for different future roles. This assessment reflected the interaction between inherited characteristics and individual development rather than relying solely on breed or pedigree.

WAFA was contacted by several families who had purchased eight-week-old puppies from the same litter after being assured that the litter came from “proven assistance dog bloodlines” and that the puppies were virtually guaranteed to become successful assistance dogs. As the dogs matured, the promised outcomes failed to eventuate, and the purchasers sought WAFA’s advice and support. Over the first 12 months of development, only one puppy demonstrated the confidence, resilience, emotional stability, sound health and trainability required to progress as an assistance dog. The remaining puppies were progressively career changed after developing inherited health conditions or behavioural characteristics—including hip dysplasia, neurological disease, persistent environmental sensitivity, anxiety in public environments and dog-directed reactivity—that made assistance work unsuitable despite appropriate socialisation, training and management by their owners. WAFA explained that while careful breeding, health testing and proven working lines can significantly increase the probability of producing suitable assistance animal prospects, no breeder, trainer or organisation can ethically guarantee that an individual eight-week-old puppy will become an assistance animal. Behaviour and working suitability emerge over time through the interaction of genetics, prenatal influences, physical development, health, learning and life experiences. Ethical assistance animal programs recognise this uncertainty and prioritise animal welfare by supporting appropriate career changes when an individual animal is not suited to the demands of assistance work.

Occupational Therapy Considerations

Occupational therapists should recognise that behaviour develops through the interaction of genetics, health, learning and environment. While breed and pedigree provide valuable information about likely characteristics, they cannot predict the suitability of an individual assistance animal.

Understanding this interaction enables occupational therapists to interpret behavioural assessments more effectively and reinforces the importance of collaborating with breeders, veterinarians and assistance animal professionals throughout the selection process.

Ultimately, successful assistance animal partnerships are not created by selecting the “perfect” genetics or providing the “perfect” upbringing. They emerge through the careful matching of an individual animal—shaped by both its biology and its life experiences—with the functional needs, lifestyle and goals of an individual person.