Bio Flashcards
(21 cards)
AO1 spec points: bio approach
influence of genes on behaviour
- genes
-genotype/phenotype
- genetic basis
influence of biological structures on behaviour
-neurons and the nervous system
-the brain
influence of neurochemistry on behaviour
-neurotransmitters
-hormones
evolution and behaviour
key assumptions of bio approach
There is a direct correlation between brain activity and cognition
Biochemical imbalances can affect behaviour
Brain physiology can affect behaviour
Behaviour can be inherited (as it is determined by genetic information)
AO1: influence of genes on behaviour
- genes
We inherit a genetic code which arguably is made up of traits that were adaptive to our ancestors in the EEA and therefore, through natural selection, became common in the gene pool.
AO1: influence of genes on behaviour
-genotype and phenotype
Genotype= the genetic makeup of an individual. The genotype is a collection of inherited genetic material that is passed from generation to generation
How this code expresses – the traits it codes for – are called the phenotype.
Phenotype= the observable characteristics of an individual. This is a consequence of the interaction of the genotype with the environment
Our phenotype – what expresses – is influenced both by our genes and by our environment.
AO1: influence of genes on behaviour
-genetic basis of behaviour
Each individual possesses a unique combo of genetic instructions
Heritability= the amount of variability in a trait within a population that can be attributed to genetic differences between individuals within that population
- the more a trait is influenced by genetic factors, the greater its heritability
eg identical twins have suggested that the variation in individual intelligence could be 60-80% due to genes
Genotype definition
the genetic makeup of an individual. The genotype is a collection of inherited genetic material that is passed from generation to generation
phenotype definition
the observable characteristics of an individual. This is a consequence of the interaction of the genotype with the environment
example of genotype and phenotype
eg: someone might inherit a recessive gene for blue eyes, but this will not be expressed if they have a dominant gene for brown eyes from the other parent. In this case we cannot determine the genotype (one blue eyes gene, one brown eyes gene) from just observing the phenotype (ie brown eyes)
AO1: The influence of biological structures on behaviour
-neurons and the nervous system
The NS is comprised of several connected systems:
-The central nervous system (CNS) comprises the brain and spinal cord.
-The peripheral nervous system (PNS) comprises the somatic and autonomic nervous systems.
The nervous system carries messages from one part of the body to another using individual nerve cells known as neurons.
Neurons transmit nerve impulses in the form of electrical signals. Many aspects of behaviour are under neuronal control, including breathing, eating, and sexual behaviour.
AO1: The influence of biological structures on behaviour
- the brain
The largest part of the brain is the cerebrum, making up about 85% of the total mass of the brain.
The outer surface of the cerebrum is called the cerebral cortex, which is responsible for many of the ‘higher-order’ functions such as thought and language.
The cerebrum is divided into two halves (known as hemispheres), which are further divided into four different parts (known as lobes):
* Frontal lobes are involved with speech, thought, and learning. * Temporal lobes are involved with hearing and memory. * Parietal lobes process sensory information such as touch, temperature, and pain. * Occipital lobes process visual information
What is the frontal lobe involved in?
speech, thought, and learning.
What is the temporal lobe involved in?
hearing and memory.
What does the parietal lobe process?
sensory information such as touch, temperature, and pain.
What does the occipital lobe process?
visual information
AO1: The influence of neurochemistry on behaviour
-neurotransmitters
When a nerve impulse reaches the end of one neuron, a chemical called a neurotransmitter is released.
This travels from one neuron to the next across a junction called a synapse.
Neurotransmitters play a role in ensuring that messages travel in the nervous system.
They also appear to play a significant role in behaviour.
For example:
Dopamine is associated with our drive or motivation.
Serotonin is an inhibitory transmitter, stabilising our mood in a way that keeps a person calm and stable. EG: Crockett et al. (2008) found that when serotonin levels are low, people tend to display increased aggression.
AO1: Evolution and behaviour
Darwin: over time, organisms become adapted to their environment through biological evolution
The mechanism behind biological evolution is natural selection. Individuals within a species differ from each other in terms of their characteristics and behaviour, and at least some of this variation is inherited.
Bc individuals must compete for access to resources, those who survive this competition and go on to reproduce will tend to have behaviours and characteristics more likely to lead to survival and reproductive success than those who do not. These behaviours will become more widespread in the population over time through natural selection.
Buss (1989) studied 37 different cultures and found similarities in human mate preferences. Women prefer men with resources (e.g., food and shelter), while men prefer physically attractive women (an indication of their fertility and reproductive value).
AO3: biological approach
str: application
lim: reductionist
lim: evolutionary explanations
Lim/str: genetic explanations
str bio app: application
Provides clear predictions, e.g., about the effects of neurotransmitters on behaviour or the influence of biological rhythms on behaviour.
This has led to significant applications of biological research in the real world. Research into the role of neurochemical imbalance in depression has led to the development of effective drug treatments.
- SSRIs & tricyclics
Likewise, research into circadian rhythms and their effect on psychological well-being has led to significant improvements in the working conditions of shift workers.
This further demonstrates the value of adopting a biological approach to the study of human behaviour.
Benefit to the economy and healthcare
Lim bio app: reductionist
The biological approach is criticised for its belief that complex behaviour can be broken down into the action of genes, neurochemicals and hormones.
For example, many explanations of mental disorders are reductionist because genes or neurochemical imbalances are believed to be the main cause of these disorders.
However, whilst a reductionist approach lends itself to scientific investigation, we cannot fully understand a behaviour without also taking account of the other factors that influence it. These include cognitive, emotional and cultural factors, all of which have a significant influence on behaviour.
Lim bio approach: evolutionary explanations
Because human behaviours can evolve through either genetic or cultural routes, a biologically based evolutionary explanation may have limited explanatory power.
Critics of such explanations claim that many established patterns of human behaviour have purely cultural origins with no obvious survival value.
For example, in many cultures, such as in China and parts of India, the sex ratio at birth is strongly biased in favour of males. This cultural preference for sons has resulted in sex-selective abortion or the withholding of resources from daughters. Unlike behaviours shaped by biological evolution, which change very gradually over many generations, behaviours shaped by cultural evolution can change more rapidly.
In China, a consequence of the more rapid change possible through cultural evolution is that there has been a change in public attitudes toward girls and a reduction in the widespread cultural preference for sons.
Lim/str bio app: genetic explanations
The dangers of genetic explanations
Recent research suggesting a genetic basis for criminal behaviour has led to concerns about how this information might be used.
Critics claim this may lead to genetic screening of the population to identify this genetic susceptibility and subsequent discrimination against those with a predisposition for criminality.
This also creates the danger that genes might then be used as convenient explanations for complicated human behaviour, despite the fact that the connection between genes and complex behaviour such as criminality is far from straightforward.
However, there may be positive consequences of such research.
If individuals discover that they have a genetic predisposition for criminality or a mental disorder such as schizophrenia, this gives them the opportunity to avoid environmental situations likely to trigger this predisposition, or to develop coping skills that would protect them from its influence.
