Natural selection is the idea that any genetically determined behaviour that enhances an individuals chance of survival and reproduction will be naturally selected.
Natural selection takes place at the level of genes, an example is altrustic behaviour, where parents risk their lives to save their offspring. The theory of natural selection would say that altruism is an adapted trait because saving offspring enhances the survival of that individuals gene pool.
Environment of evolutionary adaptiveness (EEA) is the environment that any species is adapted to and the selective pressures at the time. EEA can explain why humans have such large brains compared relative to their size, the theory would propose that the human brain is evolved in response to the complex social organisation of our species.
Those humans with abilitys to form alliances and good relationships were more likely to survive so therefore these behaviours were passed on.
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Assumption 2: Localisation of Brain Function
Certain areas of the brain are responsible for different functions
The cerebral cortex is divided into four regions: frontal, pariental, temporal and occiptal.
The frontal lobes is involved in thinking, creativity and our personalities.
The pariental lobes recieve sensory information such as temperature, touch and pain.
The temporal lobes are responsible for memory processing and auditory information processing.
The occiptal lobes are responsible for visual processing and recieve information directly from the eyes.
There are also specific areas of the brain linked to the processing of language.
The broca's area is associated with speech production and is located in the posterior portion of the frontal lobe.
The wernicke's area is involved in understanding language and is found in posterior position of the left temporal lobe.
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Assumption 3: Neurotransmitters
Neurons are electrically excitable cells that form the basisof the nervous system. The flexibilty of the nervous system is enhanced by having dendrites at the end of each neuron to connect it with others.
One neuron communicates with another neuron at a synapse where the message is relayed by neurotransmitters. These are released from presynaptic vessels in one neuron and will stimulate or inhibit receptors in the other neuron.
Neurotransmitters have been found to play a significant role in our mental health.
Too little serotonin has been found in people suffering with depression. Some antidepressant medications work by increasing the availabilty of serotonin at postsynaptic receptor sites.
High levels of dopamine have been associted with symptoms of schizophrenia. This is supported by the fact that drugs that block dopamine activity reduce schizophrenic symptoms.
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Relationship Formation
Evolutionary theory proposes relationships form with individuals who possess certain traits, particularly those that enchance successful reproduction. Males select females who are more fertile (young) and healthy, physical attractiveness. Females also seek signs of fertility and healthiness but are more concerned to find a partner who can provide resources.
The parental investment theory explains why certain relationships such as younger women and older men are formed. Female mammals invest more in their offspring so they must be choosir in finding a partner hence they will seek out a male with better resources.
The chemicals in our brain have a powerful effect on our emotions and can influence who we may enter relationships with. Dopamine for example has been associated with pleasure seeking and reward-driven behaviour so finding a partner will give us a hit of dopamine like a natural high.
Oxytocin is a hormone linked to to human bonding and increasing trust and loyalty. High levels have been linked to romantic attatachment and also in breastfeeding mothers to build a bond with their baby.
Kin selection is the natural incentive to protect our siblings to promote the survival of those who have a similar genes to us.
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