The biological approach examines how our physical makeup shapes behaviour,...
Psychology99 views·Updated 2 Sept 2026·3 pagesComprehensive Biological Approach Study Notes
annabelle @annabelle_styles
1 / 3
1
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Understanding Biological Behaviour
Your behaviour isn't just random - it all starts with biology. The biological approach assumes that everything we do has a physical cause, meaning our biological structure directly influences how we behave.
Scientists use twin studies to figure out what's inherited versus what's learned. Monozygotic twins (identical) share 100% of their genes, whilst dizygotic twins (non-identical) share about 50%. When researchers compare concordance rates between these twins, they can work out how much genetics influences specific traits.
Adoption studies offer another piece of the puzzle. By comparing adopted children to both their biological and adoptive parents, researchers can separate nature from nurture influences.
Your genotype is your complete set of genes, but your phenotype (what you actually look like and how you behave) equals your genotype plus your environment. Remember that dominant genes always show up, even with just one copy, whilst recessive genes need two copies to appear.
Key Point: Charles Darwin's theory of natural selection explains how behaviours that help survival and reproduction get passed down through generations, even if some traits become maladaptive in our modern environment due to genome lag.
2
of 3
The Nervous System in Action
Your nervous system is basically your body's electrical wiring, split into two main parts. The CNS (brain and spinal cord) is mission control, whilst the peripheral nervous system carries messages back and forth.
The peripheral system has two branches you need to know. The somatic nervous system handles voluntary movements like raising your hand. The autonomic nervous system runs the automatic stuff you don't think about, like your heartbeat.
Within the autonomic system, sympathetic arousal kicks in during stress - speeding up your heart, dilating your pupils, and prepping you for action. Parasympathetic arousal does the opposite, slowing things down and helping you relax.
Neurons are the messenger cells that make it all work. Sensory neurons carry information from your senses to your brain, motor neurons control muscle movement, and relay neurons pass messages within the CNS. Synaptic transmission happens when neurotransmitters jump across the tiny gaps between neurons, either causing excitation (firing the next neuron) or inhibition (stopping the signal).
Key Point: Think of synaptic transmission like passing notes in class - the message jumps from one neuron to another across the synapse, but sometimes the message gets through and sometimes it doesn't.
3
of 3
Hormones and the Fight-or-Flight Response
Your endocrine system is like your body's chemical messaging service. Hormones are powerful chemical messengers produced by glands that travel through your bloodstream to target specific organs.
When you face danger, your body launches the fight-or-flight response - an automatic survival mechanism that's been keeping humans alive for thousands of years. This isn't something you control; it's completely innate.
Here's how it works: your hypothalamus detects threat and activates the sympathetic branch of your nervous system. This triggers your adrenal glands to pump out adrenaline, which supercharges your body for action - faster heartbeat, sharper focus, and more energy.
The beauty of this system is its speed. Whilst your nervous system uses electrical signals for instant responses, your endocrine system provides the chemical backup that keeps you going during stressful situations.
Key Point: Your adrenal glands are your body's emergency broadcasters - when they release adrenaline, every cell with the right receptor gets the "danger alert" message instantly.
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Psychology99 views·Updated 2 Sept 2026·3 pagesComprehensive Biological Approach Study Notes
annabelle @annabelle_styles
The biological approach examines how our physical makeup shapes behaviour, exploring everything from our genes to our nervous system. It's the foundation for understanding why we act the way we do - from inherited traits to our body's automatic responses...
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Understanding Biological Behaviour
Your behaviour isn't just random - it all starts with biology. The biological approach assumes that everything we do has a physical cause, meaning our biological structure directly influences how we behave.
Scientists use twin studies to figure out what's inherited versus what's learned. Monozygotic twins (identical) share 100% of their genes, whilst dizygotic twins (non-identical) share about 50%. When researchers compare concordance rates between these twins, they can work out how much genetics influences specific traits.
Adoption studies offer another piece of the puzzle. By comparing adopted children to both their biological and adoptive parents, researchers can separate nature from nurture influences.
Your genotype is your complete set of genes, but your phenotype (what you actually look like and how you behave) equals your genotype plus your environment. Remember that dominant genes always show up, even with just one copy, whilst recessive genes need two copies to appear.
Key Point: Charles Darwin's theory of natural selection explains how behaviours that help survival and reproduction get passed down through generations, even if some traits become maladaptive in our modern environment due to genome lag.
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The Nervous System in Action
Your nervous system is basically your body's electrical wiring, split into two main parts. The CNS (brain and spinal cord) is mission control, whilst the peripheral nervous system carries messages back and forth.
The peripheral system has two branches you need to know. The somatic nervous system handles voluntary movements like raising your hand. The autonomic nervous system runs the automatic stuff you don't think about, like your heartbeat.
Within the autonomic system, sympathetic arousal kicks in during stress - speeding up your heart, dilating your pupils, and prepping you for action. Parasympathetic arousal does the opposite, slowing things down and helping you relax.
Neurons are the messenger cells that make it all work. Sensory neurons carry information from your senses to your brain, motor neurons control muscle movement, and relay neurons pass messages within the CNS. Synaptic transmission happens when neurotransmitters jump across the tiny gaps between neurons, either causing excitation (firing the next neuron) or inhibition (stopping the signal).
Key Point: Think of synaptic transmission like passing notes in class - the message jumps from one neuron to another across the synapse, but sometimes the message gets through and sometimes it doesn't.
3
of 3Sign up to see the content. It's free!
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Hormones and the Fight-or-Flight Response
Your endocrine system is like your body's chemical messaging service. Hormones are powerful chemical messengers produced by glands that travel through your bloodstream to target specific organs.
When you face danger, your body launches the fight-or-flight response - an automatic survival mechanism that's been keeping humans alive for thousands of years. This isn't something you control; it's completely innate.
Here's how it works: your hypothalamus detects threat and activates the sympathetic branch of your nervous system. This triggers your adrenal glands to pump out adrenaline, which supercharges your body for action - faster heartbeat, sharper focus, and more energy.
The beauty of this system is its speed. Whilst your nervous system uses electrical signals for instant responses, your endocrine system provides the chemical backup that keeps you going during stressful situations.
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