Issues of interest
Biological issues of interest to psychologists include:
- Different areas of the brain carry out different functions
- Synapses exist between nerve cells. Different neurotransmitters carry different neural transmissions from one synapse to another, according to our psychological functioning.
- The role of hormones in our psychological functioning.
The biological level of analysis thus emphasises that cognitions, emotions and behaviors are products of our nervous and endocrine systems.
Brain imaging technologies:
Brain imaging technologies such as CAT, PET and fMRI have made it possible to study living brains in action as various tasks are performed. This makes it possible to correlate specific areas of brain damage with specific changes in a person's personality or cognitive abilities
fMRI and the case study of HM.
fMRI and the case study of Clive Wearing.
Case Study of H.M
Case study of H.M
- H.M had brain surgery at the age of 27 in 1953.
- The surgery removed part of the brain known as the HIPPOCAMPUS to allieveate epileptic seizures
- The surgery controlled the seizures but had other effects
- H.M suffered severe memory impairment.
- His short-term memory was normal, but he couldn't transfer any memories to his long-term memory.
- He forgot news items as soon as he read them
- He could remember people from long ago, but nothing that had recently happened to them.
- He couldn't remember anything about new people he met.
- H.M had an fMRI scan many years after the surgery to see which area of the brain it was that affected his memory.
- This meant psychologists and doctors could link the hippocampus and transferral of memories to the long-term area.
Physiology and Behaviour
Explain one study related to localization of function in the brain.
Railway worker Phineas Gage - an explosion caused a pole to go right through his brain. He lost some, but not all of his mental capacities. This demonstrates that different parts of the brain have different functions.
Kim and Hirsch (1997) used fMRI to see how the brain processes language in bilingual people. One of the groups had learnt a second language as children, whilst the others had learnt later in life. Both groups had to think about what they had done the day before - first in one language and then in the other.
Kim and Hirsch investigated the Broca's area - in the left frontal lobe - and the Wernicke's area - in the rear of the brain. Broca's area manages speech production and Wernicke's area manages the meaning of language.
Both groups used the Wernicke's area no matter what language they spoke. However, those who learnt their second language as children used the same region iin the Broca's area for speaking both languages. Those who learnt later used a distinct additional area of the Broca area, close to the one activated for native tongue.
This experiment suggests languages can be handled by different parts of the brain.
Physiology and Behaviour continued
Kim and Hirsch (1997)
- Scanning appears to confirm both the Broca and Wernicke areas do serve distinct and specialised functions in language comprehension and in speech production.
- It helps explain when post-childhood learners of a foreign language tend to make errors based on mother-tongue influence
- Differences in language-learning ability may be connected with the way the learner interacts with the language. Mothers teaching an infant to speak are very tactile, auditory and visual. High school foreign language teachers tend to be less so.
- Early leaners do not bring to language learning the fears of learning vocabulary and grammar.
Neurotransmitters are substances found in the terminal buttons of a neuron. They enable stimuli to be processed and reacted to by the central nervous system. Neurons are not joined together in one long chain, but each one is separated from the adjancent one by synapses.
The neural impulse is electric, which stimulates the release of neurotransmitters. These jump across the synapses and are absorbed by receptor cells.
A person's biological and psychological situation can affect the rate of release of neurotransmitters. Drugs like alcohol and nicotine can stimulate neurotransmitter activity, and also inhibit neurotransmitter activity by covering the ends of the synaptic site.
Neurotransmitters - Dopamine
Dopamine is a neurotransmitter that helps to control the brain's reward and pleasure centres. Increased dopamine levels in the brain mean increased stimulation. For happy experiences, dopmine release sets the pleasure circuit in action. Dopamine is manufactured in the brain, in the never cell bodies located within in the ventral tegmental area and is released in the prefrontal cortex.
Dopamine is 'fired' when for example, you see a Coca-Cola advert and you immediatley get the pleasure that you associate with that drink - without drinking any of it.
Neurotransmitters - Dopamine continued
Dopamine is also partly responsible for nicotine addiction.
Nicotine stimulates adrenaline hormones, causing increased heartbeat, which in turn creates feelings of pleasure with the release of the dopamine. Those feelings also stimulate acetylcholine neurotransmitters. Withdrawal means that these newly-formed receptor sites yearn for neurotransmitters, resulting in a craving.
Fisher (2004) sampled newly fallen-in-love couples. This demonstrated that dopamine and serotonin levels are very high in the couples, and this was reflected in their behaviour. Less need for food and sleep, and couldn't get their minds off the new partner. Craving to see their new partner caused the same emotional rush of pleasure as a fix of cocaine for an addict.
Seratonin is an inhibitory neurotransmitter, employed by the nervous system in mediation of pain, sleep control and regulation of mood.
High levels of seratonin are associated with feelings of well-being and happiness.
Seratonin is alos associated with hallucinating. Kasamatsu and Hirai (1999) studied how physical deprivation affects the brain. Buddist Monks participated in the experiment, and were exposed to the cold and going without food or water for two days. The monks then percieved the presence of their ancestors. The researchers found that the hallucinations were a product of the increased seratonin levls in the monks brain.
Using one or more examples, explain the function of two hormones in human behaviour.
Hormones are chemicals released by the various glands and are carried through the blood system to where they are most needed. Some can also act as neurotransmitters, such as dopamine and oxytocin.
Hormones - Oxytocin
Oxytocin is secreted by the hypothalamus and released in two ways:
- through the pituitary gland and into the bloodstream, functioning as a hormone
- into the central nervous system where it connects to oxytocin receptors, as a neurotransmitter
Baumgartner et al (2008) - Case Study
Oxytocin - Case Study
Baumgartner et al (2008) investigated the function of oxytocin as an active hormone in economic decision-making. The aim was to investigate the role of oxytocin in causing a cheated partner to forgive and continue the trust that had existed in that relationship.
The test group was given an oxytocin supplement, and the control group a placebo. Both groups then played the trust game. The 'investor' recieves a sum of money which they are told to either keep or share with a second 'trustee' player. If the sum was shared, it would be tripled. The 'trustee' player could share the money (trust) or keep the money (betrayal). The participants played against different 'second players' in the trust game, and then against a computer in a similar risk game. The trust was betrayed in half the games. The players recieved feedback at once from those conducting the experiment. Those who had taken oxytocin continued to invest (forgave, continued to trust) at the same rate when playing with people, even though they knew they had been cheated. Those who took the placebo invested less.
Hormones - Melatonin
Melatonin is produced in the pineal gland, and is secreted as a reaction to the dark, and inhibited by light. It affects human behaviour in helping us to sleep. It's function is to communicate with the pituitary gland, which in turn sends out other hormones which make it difficult to stay awake.
SAD is a type of depression occurring at the beginning and end of winter, which seems to be related to melatonin levels. Associated behaviours include fatigue, irratability, problems concentrating and insomnia.
Avery et al (2001) Case Study
Melatonin - Case Study
Avery et al (2001).
This experiment demonstrated the function of melatonin in the behaviours of 95 SAD patients, divided into 3 groups.
The first recieved 'dawn stimulation' - an artificial lighting produced false dawn starting at 4.30AM. The second were given bright light theraphy, and the third a placebo dim red light at dawn. That last group was put under the impression that the dim red light would help their SAD symptoms. In reality, the dim red light would not have stopped melatonin secretion.
Those given dawn stimulation aand bright light therapy were able to fit their sleep patterns with their normal routines by stopping sleep-promoting melatonin. Dawn stimulation was actually more effective; it happened without the side-effects of headaches and nausea of the bright light therapy group. Those people who were given the placebo were not decieved and in most cases the SAD continues.
Effects of the environment on physiological proces
The effect of deprivation on neuro-plasticity
The brain adapts to the challenges placed on it by developing appropriate new neurons. For example, you might find maths very difficult, but with regular practice, the part of the brain that deals with maths on a challenging basis 'thickens' and handles maths more effectively. Thus, the more you exercise your brain, the more powerful it becomes. The branches of the neurons grow in numbers and connect with other neurons.
Perry (1997) compared the brain scans of three-year-olds with normal degrees of human interaction with those suffering extreme neglect.
- On the whole, brains of severely neglected children tended to be smaller than those who had been normally nurtured.
- There are large ventricular spaces in the brains of the neglected children, which would interfere with moods, sleep and regulation of anxiety. Some of the neurons of children lacking social interaction will not make enough connections to remain functional, and will wither.
Thus, the lack of early-learning experience and demanding education means an overall poorer life's experience with a less developed brain.
Genetics and Behaviour
Hutching and Mendick (1975) studied the effect of genetics on Criminal Behavior.
This research was empirically-based, on adoption situations. It sought to investigate whether criminal behavior was more likely to have been learnt from the adoption environment, or if it was guided by the specific genes towards criminal behavior.
The study found that if both the biological and adoptive fathers had criminal records, more than a third of the sons would also get criminal records. If just the biological father had a criminal records, it would drop to about a fifth of the sons. Where the adoptive father had a record, it dropped to 11%, and if neither father had a record, it dropped to 10%.
Genetics played a somewhat greater (but not exclusive) role than upbringing in influencing criminal behaviour. However, children who are adopted are often placed in a similar environment to their natural parents and Genes seem unlikely to account for criminal behaviour peaking in the 20's age group and then sharply declining.
Ethical considerations into genetic influences of
Ethical considerations to genetics and behavior
- This kind of research may pose risks to participants because of the link between genetic heritage and people’s life. Genetic information obtained from such research can also be problematic for the participant's family
- Genetic research can reveal unexpected information that may harm research participants. Examples include evidence of misattributed paternity or unrevealed adoptions within a family. Another example occurs when a person discovers from the study that he or she carries the gene for a particular genetic disorder. This may cause undue stress as the participant then fears the potential onset of the disorder
- Some groups, including Aboriginal people, may have objections to genetic study as a cultural principle. Given the existence of other forms of discrimination against such groups, and the history of the eugenics movement, this is no surprise. In such cases it is very important to consult with relevant community leaders and organizations. Consent is a community matter for many Aboriginal and ethnic groups as well as an individual concern.
Evolutionary explanations of behaviour
Evolutionary explanations of behaviours
The work of Wedekind (1995) suggests that the desire to produce healthy children that are resistant to disease is an evolutionary-based, unconscious factor in our behaviour when it comes to choosing a partner.
This is based on the MHC - the genetic compatibility behind our choice of partner. We are the product of these MHC genes that are co-dominant, meaning that both sets of inherited genes have an effect on the child's immune systems.
With his dirty shirt experiment, he showed that women preferred the scent of me with dissimilar genes - without knowing the reason why. This involved 49 women and 44 men with a wide range of MSC genes. The men wore the new t-shirts supplied for two nights in a row, and had no contact with anything that might interfere with natural body odour. The women smelt the returned, unwashed t-shirts. They then rated the smlls. The results showed that women preferred the scent of men with different genes.