Biological levels of analysis Part 2

Revision notes on biological levels of analysis part 2

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  • Created on: 13-04-12 13:32

Examine one interaction between cognition and phys

  • Cognitive neuroscience is the scientific study of biological correlates of mental processes. This area of research investigates how various brain areas are involved in cognitive (e.g. how brain damage affects memory), but in recent years researchers have also investigated how cognition and physiological processes may interact in people who meditate.
  • A number of neuroscientists are examining how meditation of mindfulness-based stress reduction (MBSR) may influence brain functions (e.g. the effect of meditation on attention, emotional reactivity and stress).
  • Interaction of cognition and physiology can be seen in the self-regulation of attention (MBSR) which seems to have physiological benefits (e.g. stress reduction).
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Davidson et al. (2004) Brain waves and compassion meditation

Aim: To investigate whether meditation can change brain activity.


  • Eight monks who had practised meditation for many years and a control group of 10 students who had one week of training participated in the study. Cognitive activities  (including meditation) produce electrical when the neurons fire. This was recorded by the EEG (electroencephalograph which records electrical activity as brain waves).
  • Participants were asked to meditate on 'unconditional compassion', i.e. open the mind for feelings of love and compassion for short periods.
  • The control group participated in a training session where they were asked to think of someone they cared about and to let their mind be invaded  by love and compassion.
  • After initial training the participants were asked to generate an objective feeling of compassion without focusing on anyone in particular.
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  • The EEG of the monks' brains showed greater activition as well as better organization and coordination of gamma waves. There was a positive correlation between hours of practice and level of gamma waves.


  • The results support the idea that attention and affective processes are skills that can be trained but more research is needed to establish if the change in brain waves is caused by hours of training and nomt individual differences before training.
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Vestergaard-Poulsen et al (2009)

Found that extensive practice of meditation involving sustained attention could lead to changes in brain structure. They found structural changes in the lower brain stem of participants engaged in long-term practice of meditation compared with age-matched non-meditatiors.

  • MRI scans of two groups of participants - meditators and non-meditations
  • The study found structural changes in brain stem regions concered with control of respiration and cardiac rhythm. The connection of neurons in this area seemed more complex in people who meditated.
  • This could explain some of the beneficial effects found in research on stress reduction techniques such as MBSR because cortisol levels are reduced and the cardiac and breathing rhythm slow down.
  • Meditative practices have already been applied in health psychologym for example Davidson et al. (2003) found that Mindfulness meditation could increase positive emotion and immune responses.
  • MBSR has also been found to alleviate pain (Grant et al. 2010).
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Discuss the use of brain-imaging technologies in i

  • Brain-imaging techniques are used in neuroscience to investigate the relationship between behaviour and brain strucutres, for example after brain damage or to find out which areas of brain are involved in which codnitive activities.
  • Brain-imaging techonology is a promising way to investigate the possible relationship between biological factors and behaviour, but so far scanning can merely register structures and activity in the brain. It is not possible to determine cause-effect relationships at this point.

Issues in brain imaging to consider

  • Brain imaging is mainly about mapping brain structures and activity in the brain.
  • Another limitation deals with localization of function. It may be possible to identify brain structures that are active during a task but, since most structures are linked to other structures in networks, it is not possible at this point to say definitely where things happen in the brain.
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MRI scan: magnetic resonance imaging

MRI scans can give detailed pictures of internal structures in the body. The body consists of water molecules. In the MRI scanner a radio frequency transmitter is turned on and it produces and electromagnetic field.

Strength of MRI

  • MRI scans are particularly to show how the blood flows in the brain and can be used to identify problems with blood circulation. They can be used for the early detection of Alzheimers' disease.
  • They are safe to use since no radiioactive material is used.

Limitations of MRI

  • They are very expensive.
  • Movement may affect the pictures.
  • They cannot say anything abut cause-effect relationships.
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Ashtari et al (2009)

Used MRI to investifate whether substance abuse (marijuana) can damage the developing brain in adolescents and young adults.

  • The researchers scanned the brains of 14 young men with a history of heavy marijuana abuse over a long period. The control group consisted of 14 young men who had not used marijuana.
  • The results of the scan indicated that there were brain abnormalities in the frontal, parietal and temporal regions of the brains of the marijuana users. The development of white matter (myelin) was affected and this could explain slow information processing in the brain.
  • The researchers concluded that early marijuana use can affect brain development negatively but since the study gave correlational data more research is needed.
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fMRI scan: functional magnetic resonance imaging
The fMRI scanner measures changes in blood flow in the active brain. This is associated with use of oxygen and linked to neural activity during information processing. When participants are asked to perform a task, the scientists can observe the part of the brain that corresponds to that function, fMRI scanning is widely used by cognitive neuroscientists and other researchers and its use has increased enormously over the last 10 years.

Strengths of fMRI

  • It does not use radioactive substances.
  • It can record activity in all regions of the brain.

Limitations of fMRI

  • The focus is mostly on localized functioning in the brain and does not take into account the distributed nature of processing in neural networks.
  • The results are correlational so it is not possible to establish cause-effect relationships.
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Harris and Fiske (2006) used fMRI scans to study students' brain processes as a reponse to being presented with pictures of extreme outgroups. This study in social cognition aimed to find the biological correlates of stereotypes and prejudice.

  • The researchers scanned students while they were watching either pictures of different humans or objects. It was predicted that the medical prefrontal cortex would be active when participants looked at humans but not when they looked at objects.
  • This was found except when participants looked at pictures of people from extreme outgroups such as the homeless and addicts. Brain regions related to 'disgust' were actovated amd tjere was mp activity in the prefrontal cortex. 
  • The researchers concluded that this indicated a dehumanization of the outgroups.These groups were apparently viewed as 'disgusting objects' and not people.
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Discuss the extent to which genetics influences be

Gene mapping
Attempt to determine the effect of a particular gene on behaviour such as psychological traits (temperament), psychological disorders (e.g. depression or schizophrenia) or various physiological conditions.

Caspi et al. (2003) Longitudinal study on the possible role of the 5-HTT gene in depression after experiences of stressful events

  • The 5-HTT gene influences the level of serotonin, which is known to play a role in controlling mood,
  • The researchers compared participants with a normal 5-HTT gene and a mutation of the 5-HTT gene with shorter alleles. Both types are quite frequent in humans but the long allele is slightly more frequent (57%).
  • The researchers found that participants who carried a mutation of the 5-HTT gene and who had experienced many stressful events were more likely to become depressed after stressful events were more likely to become depressed after stressful events than those participants who carried the normal 5-HTT gene.
  • The 5-HTT gene could indicate a vulnerability to depression after stress and the researchers speculated whether the gene could moderate individual responses to environmental factors. 
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  • Since a large proportion of the population carries the mutation of the 5-HTT gene that makes them susceptible depression after traumatic events, it can be difficult to conclude that the gene is a major contribution to depression. People who did not carry the mutation also became depressed.
  • The study showed a correlation between the presence of 5-HTT short allele and depression but it is not possible to establish a cause-effect relationship.
  • Genes contribute to some extent to behavioural traits and disorders but it is not clear hwo environmental factors influence genes. Environmental factors were included in study (stressful events) but there is no evidence against the idea that it could be the stressful events (environmental factors) that made people depressed.
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Twin studies

  • Monozygotic twins come from the same egg and share 100% of their genes. Dizygotic twins come from two different eggs and share around 50% of their genes. Siblings share 50% of their genes.
  • The researchers calculate concordance rate (the likelihood or probability that if one indicidual has the trait the other will also have it). The concordance rate is assumed to establish if or to what extent a certain trait in inherited.
  • In twin studies, one twin acts as control for the other twin. The classic twin study only studied concordance rates and did not include environmental factors. In some cases MZ twins were raised apart and in these cases it was assumed that differences were raised apart and in these cases it was assumed that differences were due to environmental factors.
  • In twin research, sets of MZ are compared with sets of DZ twins for a particular trait or disorder. High concordance rates in MZ twins and lower concordance rates in DZ twins for the same behaviour indicate that the trait or disease is linked to genes. Differences within pairs of indentical twins are attributed to environmental factors.
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Bouchard et al (1990) Twin study investigating inheritance in intelligence

  • This study used a self-selected sample of MZ twins who had been reared together (MZT) and MZ twins who had been reared apart (MZA) to investigate concordance rates for a number of variables such as IQ.
  • The results showed that for IQ (measured by a standardized intelligence test called WAIS) the concordance rate was 69% for MZA and 88% for MZT.
  • The researchers concluded that environmental factors do play a role in development of intelligence but IQ is to a large extent inherited and that70%  of the observed variation in the sample could be attributed to genetic variation.
  • They claim that the results indicate that in a sample like the one in the study (white, middle-classed in an industrialized nation) genetic inheritance IQ accounts for around two thirds of the observed variance of IQ.
  • They also said that their findings do not indicate that IQ cannot be increased, that is influenced by environmental factors.
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Problems in genetic research

Genetic research cannot at this point determine the extent to which genetic inheritance influence behaviour because:

  • Genes interact with environmental factors in complex ways. It is difficult to measure relative influence of genes and environmental factors.
  • Knowledge about genes is still limited.
  • There are problems in genetic research (e.g. concordance rates in twin studies cannot say anything about cause-effect relationships). MZ twins being treated in the same way as DZ twins may be wrong (the "equal environment assumption" may be flawed) and this limits the possibility of drawing meaningful conclusions from twin studies.
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Examine one evolutionary explanation of behaviour

  • The theory of evolution, suggest by Charles Darwin, is based on the assumption that living organisms face environmental challenges. Organisms that adapt the best have a greater chance of passing on their genes to the next generations.
  • Organisms with specific genetic traits that enhance survival are said to be naturally selected. Natural selection is a crucial evolutionary process in Darwin's theory.

Fessler et al (2005) Elevated disgust sensitivity in the first trimester of pregnancy

Aim: To investigate if disgust sensitivity in the first trimester of pregnancy was elevated as predicted.


  • A Web-based survey was completed by 691 women recruited through pregnancy-related Web sites. No compensation was offered for participation. The women's mean age was 28.1 years.
  • On the Web-based questionnaire, the participants (1) indicated their current level of nausea using a 16-point scale and (2) answered questions to test their disgust sensitivity in eight different areas (e.g. food; contact with animals, body products, and dead animals; hygiene; contact with toilets). 
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  • Overall, disgust sensitivity related to food and body products in women in the first trimester was higher compared to those in the second and third trimesters.
  • Disgust was particularly elevated in relation to food, which was exactly what the researchers had predicted.
  • Food-borne diseases are particularly dangerous to women in the first trimester and therefore it was predicted that disgust sensitivity related to food would be high. This was supported by the results.
  • The results may indicate that nausea and vomiting are evolved behaviour because they limit the likelihood that pregnant women will eat dangerous food.
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  • The data was collected through questionnaires. Self-reports may not be reliable. This is not an effective way of measuring disgust. It would have been more reliable to confront participants with real disgust-eliciting objects.
  • This effect sizes were not big but significant. The findings are supported by other studies (e.g. Curtiss et al. 2004) showing that images that threaten the immune system are judged as more disgusting.

Evaluations of evolutionary explanations:

  • It is difficult to test evolutionary theories and not much is known about the life or early humans.
  • Evolutionary explanations tend to focus on biological factors and underestimate cultural influences.
  • According to Davey (1974) disgust for spiders may be explained by people's need to find tangible causes of illness and disease when the causes were unclear.
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Discuss ethical considerations in research into ge

Ethical considerations in genetic research

There are specific issues of concern in genetic research within the biological level of analysis. This is particularly true in the search for genes involved in abnormal behaviour, but it is also relevant in research on genetic influence on disease, intelligence, personality, or health. The main reasons for concerns are:

  • Knowledge about the role of specific genes in behaviour is still limited so researchers should be careful about making definite conclusions. Genetic research is often reductionist as it does not include environmental factors.
  • Genetic research is correlational by nature so one should be careful to make definite conclusions about the risk of developing a disease.
  • It is not certain that genetic research, like the Human Genome project, is ethically neutral. There are historical examples of misuse of ethically sensible data (e.g. eugenics in Nazi Germany) and is not guaranteed that data could not be misused again (Wallace 2004).
  • Genetic research into complex behaviour such as homosexuality is controversial because of the social meaning and significance of homosexuality. Genetic research could result in stigmatization and discrimination as many societies are homophobic. The search for the "gay gene" has generally raised controversy.
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Caspi et al. (2003) Longitudinal study on the possible role of the 5-HTT gene in depression after experiences of stressful events

  • The researchers compared participants with a normal 5-HTT and a mutation of the 5-HTT gene with shorter alleles. Both types are quite frequent in the human population but the long allele is slight more frequent (57%).
  • The researchers found that participants who carried a mutation of the 5-HTT gene and who had experienced many stressful events were more likely to become depressed after stressful events than those participants who carried the normal 5-HTT gene.


It is not clear what to do with knowledge from genetic research and genetic screening at this point - both at an individual level and in society. For example, being genetically predisposed to depression does not mean that a person will develop depression. The results of genetic screening for depression could cause personal distress and have a negative impact on someone's life (e.g. if based on this they decided not to have children).

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Ethical considerations in all genetic research

The DNA profile of each human is unique, except for MZ twins who are 100% genetically similar. The fact that one twin acts as a control in genetic research is the major reason why twins are often used to determine heritability. Genetic information is often seen as special because it is assumed that genes determine behaviour and genes are associated with personal identity. In reality, genetic information can only reveal a potential risk.

Anonymity and confidentiality

  • Participants in a genetic study must be sure that their anonymity and confidentiality is protected but in family and twin studies it can be difficult to ensure this fully. This is also the case in the research of rare disorders.
  • Participants have a right to know who owns the genetic information and how it will be used in the future (e.g. if their access to insurance or employment could be compromised because of genetic data).
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Informed consent and the right to refuse or withdraw

  • Participants have a right to be fully informed about what the research is about, the procedures, what could be the result of the study and how the information will be used.
  • Research into genetic influences on behaviour could potentially pose risks to participants and the genetic information could be misused.
  • Genetic research can reveal information that is unexpected or a source of distress to participants (e.g. when a participant has no sign of a disorder but the data shows a genetic predisposition).
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