The Biological level of analysis
Human beings are biological systems. There is little dispute that our cognitions, emotions and behaviours are products of biological processes in the anatomy and physiology of our nervous and endocrine systems...
But is this the whole story? Can an analysis of our biology provide a full explanation for our actions? Understanding the huge advances in our understanding that have been brought about by a biological analysis of human behaviour, but also appreciating the limitations of this approach, is the main goal of this unit.
But is this the whole story? Can an analysis of our biology provide a full explanation for our actions? Understanding the huge advances in our understanding that have been brought about by a biological analysis of human behaviour, but also appreciating the limitations of this approach, is the main goal of this unit.
Specification extract:
Over the last few centuries, discoveries have shown that: • the nature of the nervous system is electrical in part (Galvani) • different areas of the brain carry out different functions (Broca) • small gaps exist between nerve cells that require the action of chemicals to carry neural transmissions across these gaps • hormones play an important role in our psychological functioning. Since the 1960s, with the invention and development of brain imaging technologies (for example, CAT (computerized axial tomography), PET (positron emission tomography), fMRI (functional magnetic resonance imaging)) it has become possible to directly study living brains in action as various tasks are performed, and to correlate specific areas of brain damage with specific changes in a person’s personality or cognitive abilities. Advances in psychopharmacology—the field of medicine that addresses the balance of chemicals in the brain—have led to the development of new medications for problems as diverse as depression, anxiety disorders and Alzheimer’s disease. After Darwin published his theory of evolution through natural selection, animals came to be studied in order to shed light on human behaviour. With the completion of the human genome project, the chimpanzee genome project, and with other species having the full structure of their DNA mapped, the contribution of genes to our cognitions, emotions and behaviour is becoming better understood. Behavioural genetics takes the skills of biological analysis used to study the differences between species and applies these skills to studying individual differences in humans. These are the components at the biological level of analysis needed to understand our complex biological system and the psychological functions it supports. |
General learning outcomesAs well as the specific learning outcomes, you should know the following:
• Outline principles that define the biological level of analysis (for example, patterns of behaviour can be inherited; animal research may inform our understanding of human behaviour; cognitions, emotions and behaviours are products of the anatomy and physiology of our nervous and endocrine systems). • Explain how principles that define the biological level of analysis may be demonstrated in research (that is, theories and/or studies). • Discuss how and why particular research methods are used at the biological level of analysis (for example, experiments, observations, correlational studies). • Discuss ethical considerations related to research studies at the biological level of analysis. |
The Assumptions of the Biological Level of Analysis
(you MUST know these!)
- OHuman behaviour is strongly influenced by our genetic make-up and our genetic inheritance. This means that patterns of behaviour can be inherited.
- The central nervous system, especially the brain, is essential for thought and behaviour to take place. An understanding of brain structures and their functions can explain both behaviour and thought. The key unit/building block of the nervous system is the neuron.
- Chemical processes in the brain are responsible for psychological functioning, and an imbalance of chemicals in the brain may cause certain types of mental disorders, for example bipolar mood disorder. These chemicals may be neurotransmitters, or endocrine hormones.
- Humans have evolved biologically, through Darwinian evolution, and have much in common with other animals, especially those close to us on the ‘evolutionary tree’.
- Many aspects of human behaviour can be explained in terms of localised areas of the brain
- Damage to certain parts of the brain can lead to characteristic behaviours or behaviour changes
- Humans and animals share the same basic biological structures; therefore research on animals can be used to inform us about human behaviour.
Once you know the main assumptions of an approach, it should be possible to explain almost any behaviour from the point of view of the approach. It is also possible to begin to work out which methods the approach will use.
Activity 1 - how might the biological LoA explain the following behaviours?Decide which of the major ideas of the biological LoA (such as evolution, genetics or neurotransmitter and hormone levels) would help explain the following behaviours most successfully.
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Introduction to some key ideas of the BLoA
NeuronsA neuron is a specialised nerve cell which communicates with other neurons in the brain or nervous system, or with muscles or organs in the body, such as eyes or heart. It is estimated that there are over 100 billion neurons or nerve cells in the human nervous system: some are very small and some are over a metre long.
There are three types of Neurons, motor neurons, sensory neurons and interconnecting neurons. Motor Neurons carry messages away from the brain and spinal cord to the organs and muscles in the body. Sensory Neurons carry messages from receptors such as the skin to the brain and spinal cord. Interconnecting Neurons are found only in our visual system brain and spinal cord. They receive messages from the sensory neurons and pass these messages to other interconnecting neurons or to motor neurons. Most interconnecting neurons are in the brain. Use your notes or the internet to practice labelling the diagram on the right. At the end of each neuron is a junction called a synapse, where the neuron communicates to either another neuron or a destination organ such as a muscle... |
SynapsesA synapse is a specialised gap that allows electrical messages from one neuron to transfer to another. This is known as synaptic transmission.
When an electrical impulse travels down the axon it arrives at the terminal buttons. This arrival triggers the release of neurotransmitters (Chemicals which pass on the electrical message). These chemicals are released into the synaptic gap/cleft and some are picked up by the post-synaptic neuron. If transmitted successfully the message is carried onto the next synaptic terminal. Synapses are the places that the vast majority of drugs (both medical and recreational) act upon us. |
Localisation of cortical function
The human brain is undoubtedly the most complex and remarkable structure within the body. It has around 100 billion neurons and around 100 trillion synapses!
There are different areas within the brain that are responsible for specific functions. This is called the localisation of function. The brain is also split into two hemispheres (sides of the brain) and when one side of the brain is better at a function than the other this is known as lateralisation. You will study the functions of some of these localised areas in more detail. A simple introduction to some of the divisions of the brain can be seen to the right. Notice that the cerebral cortex is divided into four lobes. |
The Frontal Lobe – Located at the front of our brain and responsible for reasoning, planning and our personality. It is also responsible for movement as the motor cortex is found at the back of the frontal lobe. Movement on the right side of the body is controlled by the left hemisphere of the brain and vice versa.
The Parietal Lobe – It is located behind the frontal lobe and above the occipital lobe. It is concerned with spatial awareness and our sensory information such as touch, pressure temperature and pain. The specific are which deals with this sensory information is known as the somatosensory cortex; this runs alongside the motor cortex in the parietal lobe.
The Temporal Lobe – Located at the sides of our brain and is responsible for auditory ability and memory acquisition. The auditory cortex is responsible for analysing speech based information. Damage to this area can cause Wernicke’s aphasia (named of Karl Wernicke who found the area) this is when individuals have difficulty understanding language.
The Occipital Lobe – Located at the back of the brain behind the temporal and parietal lobe and is responsible for visual information. Damage to the left hemisphere of the visual cortex may reduce the vision in our right eye.
The Parietal Lobe – It is located behind the frontal lobe and above the occipital lobe. It is concerned with spatial awareness and our sensory information such as touch, pressure temperature and pain. The specific are which deals with this sensory information is known as the somatosensory cortex; this runs alongside the motor cortex in the parietal lobe.
The Temporal Lobe – Located at the sides of our brain and is responsible for auditory ability and memory acquisition. The auditory cortex is responsible for analysing speech based information. Damage to this area can cause Wernicke’s aphasia (named of Karl Wernicke who found the area) this is when individuals have difficulty understanding language.
The Occipital Lobe – Located at the back of the brain behind the temporal and parietal lobe and is responsible for visual information. Damage to the left hemisphere of the visual cortex may reduce the vision in our right eye.
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Methods of the BLoA
Some of the main methods used by the BLoA include:
Make sure you understand what is meant by all of these terms. As most of the research methods are scientific in nature, with variables controlled and carefully measured, the aim is to reach reliable and valid conclusions. However, scientific research (especially lab experiments) have negative as well as positive aspects. |
Advantages of experiments
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Disadvantages of experiments
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Ethical considerations at the BLoA
The main ethical principles which Psychologists must follow concern:
- Consent
- Confidentiality
- Debriefing
- Deception
- Protection of participants from harm
- Right to Withdraw
- Observation
These are the same for all psychology researchers, with some being especially relevant to work at the BLoA. If you need a reminder about what each term means, you can check this IB blog site. You should know what each of these principles means for psychology researchers.
Ethics Mnemonic
Create a mnemonic for the letters CCDDPOR (though it doesn't have to be in that order), which will help you to remember all of the ethical principles. For example (though you should make your own)...
Obviously Dirty Doughnuts Can Cause Problematic Rashes
- Consent
- Confidentiality
- Debriefing
- Deception
- Protection of participants from harm
- Right to Withdraw
- Observation
These are the same for all psychology researchers, with some being especially relevant to work at the BLoA. If you need a reminder about what each term means, you can check this IB blog site. You should know what each of these principles means for psychology researchers.
Ethics Mnemonic
Create a mnemonic for the letters CCDDPOR (though it doesn't have to be in that order), which will help you to remember all of the ethical principles. For example (though you should make your own)...
Obviously Dirty Doughnuts Can Cause Problematic Rashes
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Practice identifying breaches of the ethical code: watch the video on the right and count how many of the principles are broken. Also, imagine how the experiment could be redesigned to make sure they are not broken. Would it be possible? Think this is bad?... Then have a look at the top ten unethical psychology experiments on Listverse. For two personal favourites of mine, look up Sheridan and King (1972) or Jouvet (1967). |
Assignment 1 - Practice exam questionTry to write at least 2/3 of a page from memory on the following essay title:
Outline principles that define the biological level of analysis (8) |
Assignment 2 - Supernormal stumuliThis brilliant cartoon from Stuart McMillen is a great introduction to the various biological influences on our behaviour... and also beautifully drawn.
What aspects of the BLoA does it illustrate? |
Revision |
Extension |