Individual differences and developmental psychology

How are individual differences seen in biological psychology?

• In the case studies of brain damaged patients

• Freud’s theory of personality

How does Phineas Gage show individual differences?

Phineas Gage has a large mental rod driven through his head, and had damage in both the left and right prefrontal areas, causing a defect in rational decision making and the processing of emotion. This led to changes in this personality, such as heightened levels of aggression. However, these findings are unique to Phineas Gage and may not be generalisable to other people due to individual differences, which might mean the same effects id this biological damage are not observed in others.

Evidence to suggest that there are not individual differences in biological psychology?

There are more similarities than differences in brain structure and functioning as most people’s brains work in predictable ways. For example, the effect of recreational drugs on synaptic transmission. Heroin is an agonist, so binds to opioid receptors to trick the brain into releasing endorphins which relieves pain / reduces stress and increases dopamine, improving mood and giving the user a feeling of euphoria. This mode of action is the same for everyone and therefore the damage caused to the brain due to abusing this drug will be the same for everyone. This indicates that we can use the case study of one drug addict to explain the neurological effects of that drug on all addicts as individual differences do not have an effect.

How does Freud’s theory of personality show individual differences?

According to Freud, childhood experiences throughout the development of the personality can lead to individual differences in adult personality (eg- an overdeveloped ID can lead to a very selfish and demanding personality (as it relates to the pleasure principle) whereas an overdeveloped superego (morality principle) leads to an adult personality which is overly moralistic and judgemental. This might also lead to individual differences in aggression because an overactive ID may lead to more aggressive behaviour when they don’t receive instant gratification for urges, whereas someone with an overdeveloped superego is less likely to be aggressive as they are extremely obedient.

What aspects of biological psychology relate to developmental psychology?

• The role of evolution on human development

• The role of hormones in human development

What is the role of evolution on human development?

Evolutionary theory suggests that those most suited for survival will survive and these individuals are more likely to have reproductive success and therefore pass on these advantageous genes. Genetic mutations will occur within a species, some of which will lead to an adaptive advantage leading to those genes being more likely to be passed on to the next generation, which explains how humans have developed over several generations. In challenging environments, aggression would help our ancestors gain territory, resources and negotiate status. Therefore, human behaviour such as aggression has been shaped by the process of natural selection and the evolutionary advantages id exhibiting this behaviour, which can explain its prevalence in society today.

What are the role of hormones on human development?

Hormones affect how we develop. For example, testosterone is needed to produce male features such as muscle strength, body and facial hair and a deeper voice. Testosterone can also lead to more aggressive, irritable behaviour. Cortisol is secreted to protect the body against the effects of stress and might be responsible for regulating aggression from stress. Cortisol seems to inhibit aggression.