Put the boxes in the correct order of the process of hormones Stimulating hormones Releasing hormones Endocrine system Hypothalamus Pituitary gland Use the pictures to explain Ditzen's study Ditzen revision Use the pictures to explain Baumgartner's study The role of one gene on behaviour Identify the debate • You already know that in the introduction you should refer to the command term. E.g This essay will discuss how genes influence depression with reference to research by ____________ and _____________. • In 22 markers, you are required to identify the debate in your introduction • This only needs be a sentence. For example: There is debate as to whether genes influence depression or whether it could be due to environmental factors. This essay will discuss how genes influence depression with reference to research by Caspi and Chiao and Blizinsky/Troy One of the principles of the Biological Approach is that behaviour can be inherited. In early psychology debates, behaviour was seen as either nature or nurture. Today it’s more of an interactionist approach. Diathesis stress model: Belief that we often have a genetic vulnerability to a disorder, and if we experience the right environmental stressors, then these genes will be expressed. (think back to Caspi) Fill in the gaps • A gene is a segment of ______ in a particular location on a ________ that acts by directing the synthesis of proteins. The human genome (the whole of human DNA) has approximately 20,000‐25,000 genes contained on _____ pairs of chromosomes. Genes have been shown to affect human behaviour, but not _______: there are no genes ‘for’ any behaviour – no genes for depression or alcoholism, for example. What there is instead is inheritance of a particular _________ to stress, maybe, or the effects of a particular neurotransmitter or group of neurotransmitters, which are in turn affected by genetically‐inherited ____________ (changes) on neurotransmitter transporter genes. The theory that will be evaluated in this essay is that genes and environment interact to affect behaviour. CHROMOSOME/ DIRECTLY/ SENSITIVITY/ DNA/ 23/ POLYMORPHISMS What is the nature vs nurture debate? In Psychology, it’s generally accepted that both sides must be considered when looking at human behaviour (even by biological psychologists) NATURE A genetic predisposition NURTURE An environmental trigger Certain characteristic IQ Depression NATURE OR NURTURE? Genetics: background theory • Behaviour is the interaction of genetic inheritance and environmental factors. • We inherit our DNA – from our parents. However, when psychologists argue that behaviour may be inherited, what exactly does that mean? • What is inherited is the genes that give rise to the development of specific physiological processes that contribute to specific traits and behaviour. It is not probable that a single gene is responsible for such complex behaviours as intelligence, criminal behaviour, altruism or attachment. Instead, what is inherited may be the building blocks for such complex behaviours. Diathesis stress model • Psychologists argue that an individual may have a genetic predisposition towards a certain behaviour; however, without the appropriate environmental stimuli, the gene is not “turned on” and the behaviour is not expressed. • This model argues that depression may be the result of the interaction of a “genetic predisposition” and environmental stress. The model predicts that an individual with certain genes, when exposed to a stressful environment, is more likely to develop depression than someone who does not have those genes. Mental health jam jar Look at the image on the right. Think about this - what might be people's mental health vulnerabilities and stressors? Do you think that you can have any biological vulnerabilities? Genetic inheritance • Genetic arguments are based on the principle of inheritance. Genes and their DNA are passed down from parents to their offspring, with 50% of our genes being inherited from each parent. • Humans have 23 pairs of chromosomes, with approximately 20.000 – 25.000 genes. • We now know this number as a result of the worldwide research initiative started in 1990 called the Human Genome Project. • The project which was completed in 2004, maps the sequences of the human genome. While this is an important step in understanding the complexity of human behaviour e.g. developing treatments, the exact role of specific genes in many behaviours remains unknown. For a 9 marker, use this study Studies: Caspi – 5HTT gene Chiao and Blizinsky – cultural differences 😕 Troy – individual differences in terms of emotional regulation Deeper critical thinking - Cultural dimensions may protect against the genetic vulnerability/ or may lead to stigma (Chiao and Blizinsky study) - Emotional regulation is important (Troy study) - The neurogenesis theory: role of cortisol - Gender differences in expression of the gene - Implications: epigenetics and passed onto next generation - Reductionism: ignores cognitive factors in depression e.g. negative schemas. However, Caspi’s study is more holistic as it considers the relationship between genes and environment 5htt gene and depression • Write down 4 symptoms of depression • An affective (mood) disorder that negatively affects how you feel, the way you think and how you act. Symptoms include: - Fatigue and decreased energy - Feelings of worthlessness - Insomnia - Over eating and loss of appetite - Persistent sad, anxious, or "empty" feelings - Loss of interest in activities or hobbies once pleasurable. Prevalence of depression • Depression is higher in women than men - Women are nearly twice as likely as men to be diagnosed with depression • Depression is higher in the West than the East - Rates of clinical depression are greater in the West than in the East. The majority of easterners do not know the names of mental illnesses Study recap CASPI • Which country were the participants from? New Zealand Canada Denmark • Between which ages was their depression monitored? 16-20 21 and 26 26-30 • The participants with 2 short alleles only reported more depression if they experienced a… Family member with depression Environmental stressor • This study was quasi. True False Poor diet Fill in the blanks on Caspi’s study Linking back to the question • How are you going to use this study in an essay? Write an explanation of the findings and link back to the question below: ‘Discuss the role of genes in behaviour’ Participants with 2 alleles of the 5HTT were more likely to experience depression in the presence of an environmental stressor. This is because the 2 short alleles, increases the reuptake of serotonin from the synapse before it’s had a chance to attach to receptors on the post-synaptic neuron. There demonstrates the influence of the 5HTT gene on the behaviour of depression, as this behaviour wasn’t seen in participants with two long alleles. However it is important to note that the gene only influenced behaviour when an environmental trigger was present e.g. losing one’s job. This suggests that the diathesis stress model may be at play here, where the gene provides a vulnerability to depression and the environment is the trigger. Overall, this shows how genes can influence behaviour. PEEL one of the evaluation points below for Caspi’s study Question to link back to: Discuss the role of genes on behaviour Point – There are weaknesses to this study Evidence – This is because the research method of Caspi’s study was ____________________ Explain – This is bad because ______________________________________________________________ ______________________________________________________________, and the results may actually be due to extraneous variable like _____________________________. Link: Therefore, this study ______________________________________________________________ ______________________________________________________ Question to link back to: Discuss the role of genes on behaviour Point – There are weaknesses to this study Evidence – This is because the research method of Caspi’s study was correlational Explain – This is bad because it becomes difficult to determine cause and effect, and the results may actually be due to extraneous variable like, family and friend support at home and in their social lives. Link: Therefore, this study may provided limited evidence about the influence of the 5HTT gene on the likelihood of depression. Starter: 1) What does the 5HTT gene do? Use the picture on the right 2) What are 2 short alleles on the 5HTT gene thought to do? Use the picture Read Chiao and Blizinsky study on page 31 • How are you going to use this study in an essay? Write an explanation and link back to the question below: ‘Discuss the role of genes in behaviour’ The participants in the East who had a higher prevalence of the 2 short alleles on the 5HTT gene actually had a lower prevalence of depression. This counters the idea that the two short alleles increases serotonin reuptake, which as a result would lead to less serotonin attaching to receptors and passing on the message to stabilise mood. Therefore, this suggests that the role of the 5HTT may not play a large role in depression, and instead the environment may be more influential. Read Chiao and Blizinsky study on page 31 • However, you want to be critical – you can offer alternative conclusions. See below However, it is worth nothing that there may be some reasons for this. Firstly collectivist cultures value the group over the individual, so perhaps the emotional symptoms of depression have been addressed internally by the group, and the support they receive from the group minimises the effect of the gene on their behaviour. In line with the diathesis stress model – perhaps the support from the group is a protective factor against the 2 short alleles, meaning the gene does not sole behaviour , only a genetic vulnerability. Alternatively, there is a stigma about depression in a lot of Eastern cultures, so perhaps the 2 short alleles on the 5HTT does increasing depressive behaviour but it is being under reported. To address this, data triangulation should take place where the study is repeated with some other collectivist countries and more participants to see if the results can be replicated. If they can, then it’s likely these results are valid. Or, method triangulation could be conducted where a follow up anonymous questionnaire could be conducted to gain some richer insight into potential depressive symptoms, without the fear of stigma from the disorder. Emotional regulation 2 short alleles was the children’s genetic vulnerability, the high stress environment was the environmental trigger – BUT there’s a 3rd factor that may prevent the development of the disorder Troy: read the study on page 33 • How are you going to use this study in an essay? Write an explanation and link back to the question below: ‘Discuss the role of genes in behaviour’ At-risk children (those who carried 2 short alleles on the 5HTT gene and who lived in high stress environments) exhibited more depressive symptoms than other groups. Importantly, at-risk children who used effective emotion regulation did not exhibit increased depressive symptoms. This suggests that the two short alleles on the 5htt gene provides a genetic vulnerability to depression, as serotonin is being re-uptaken too soon before it has had the chance to attach to receptors on the postsynaptic neuron. The diathesis stress model is at play here too and it suggests there may be a 3rd variable involved. If you have the genetic vulnerability for depression and also a stressful environment, emotional regulation may be an extremely important protective factors against the disorder. Given that emotion regulation is learnable, these results also have strong public-health implications. This suggests that genetics may influence depression, but that learnt traits may have a bigger contribution to the onset of the disorder. Cortisol • Cortisol is the body’s stress hormone. The higher your levels the higher your stress. • It’s produced by the hypothalamus, which makes __________ hormones, which go to the pituitary gland which makes ___________ hormones which target the adrenal gland. An example of how hormones affect a response (fight/flight) HPA axis (hypothalamic-pituitary-adrenal). - Your hypothalamus instructs the pituitary to tell the adrenals to make hormones such as adrenaline, which is released during the fight or flight stress response. Can you apply any of these points below to the research by Maguire or Draganski? For deeper critical thinking Reductionism – Is it focusing on behaviour being caused by one small factor or one approach? Individual differences – Not necessarily everyone may behave in the same way. Can you think of any examples of different behaviour? Cultural differences – Does it explain the behaviour of people in a different culture? How might different cultures behave? Give some examples Triangulation – (data, method, researcher). Use this in response to issues with sample size, type of sample or research method used. This can attach itself to population/ecological validity points. Assumptions – What assumptions are being made? E.g. that the questionnaire collected natural responses. Could their behaviour be influenced by something else? CRITICAL THINKING • RICTA – reductionist to think genes influence behaviour – depression could be caused by negative schemas or stressful life events. • RICTA – individual differences. Some people who 2 short alleles on the 5HTT gene may not develop depression, even in the presence of a stressful life event • RICTA – data triangulation and cultural differences: most research is conducted with young samples in the west. Repeat to see if the findings are reliable • RICTA – assumptions: measures of depression usually rely on questionnaires. This could be subject to social desirability bias, especially if there’s stigma surrounding mental health. Method triangulation could follow up with an anonymous questionnaire where participants might feel more comfortable disclosing information Deeper critical thinking - Gender differences in what triggers the gene (Leppert, 2016) • Boys and girls carrying the short 5-HTTLPR allele react to different kinds of environmental factors. - Males affected by: living in public housing rather than in own owned homes/ living with separated parents - Females affected by: traumatic conflicts within the family. • Second, the responses of males and females carrying the short 5-HTTLPR allele to environmental stress factors go in opposite directions. Whereas females tend to develop depressive symptoms, males seem to be protected from depression – is this because there’s stigma?? • Conclusion: both the molecular and the psychosocial mechanisms underlying depression may differ between boys and girls. Deeper critical thinking (research support for diathesis stress model in elderly) (Munin, 2005) • Short alleles are a predictor of depression in elderly people following a hip fracture • Prospective, observational study of 23 elderly rehabilitation-hospital patients during their inpatient stay. Depressive symptoms were assessed by Hamilton Rating Scale for Depression . Subjects were grouped according to the alleles on their 5HTT gene. • Results: Subjects with a short allele on the 5htt gene had significantly higher depression scores over 14 weeks of follow-up. • Depressive symptoms and major depressive disorder in elderly persons after a stressful medical event may be associated with 5-HTTLPR genotype. This finding requires confirmation in a larger sample. • But does fit with Caspi’s argument that you need a stressful life event to trigger the onset of depressive symptoms. Hip fracture could be the stressful life event. What about epigenetics? Gene expression • Not all genes are expressed at all times. • Genes can be switched on and off. This is gene regulation, resulting in differential gene expression. • Regulation of gene expression results in epigenetic changes which can be attributed to the environmental influences, and in this sense, it is a study of how nurture affects nature. • Therefore, having a gene for a particular behaviour, does not necessarily mean that an individual will exhibit that behaviour Epigenetics: A branch of genetics that focuses on "gene expression" - that is, how environmental factors may "activate" genes. What causes genes to be switched on or off? Signals from inside or outside the body can cause genes to be switched off or on. • Internal signals: Presence of hormones, other chemicals and presence of other genes. • External signals: Environmental events such as temperature, sunlight, diet, stress and physical activity Genes are constantly being switched on and off in response to internal and external cues. Real world example Plastic in the environment is influencing the physiology of unborn children by influencing their genetic expressions Essay plan task • Write an essay plan for the following question: Outline the role of one gene in behaviour • Write an essay plan for the following question: Discuss the role of one gene in behaviour Outline the role of one gene in behaviour Intro: - Refer to command term (but be explicit to say the one gene you are focusing on (5HTT gene) and the behaviour you’re focusing on (depression)/ what are genes/ nature vs nurture debate/ diathesis stress model/ what is depression/ the 5HTT gene and what it does/ what 2 short alleles are thought to do Study: Caspi (for a 9 marker) - Introducing sentence: There has been research to support the role that genes have on behaviour - Aim, procedure - Findings and conclusion: these need to be detailed (see slide 31). Discuss the role of one gene in behaviour Intro: - Refer to command term (but be explicit to say the one gene you are focusing on (5HTT gene) and the behaviour you’re focusing on (depression)/ what are genes/ nature vs nurture debate/ diathesis stress model/ what is depression/ the 5HTT gene and what it does/ what 2 short alleles are thought to do Study 1: Caspi - Introducing sentence: There has been research to support the role that genes have on behaviour - Aim, procedure - Findings and conclusion: these need to be detailed (see slide 31). - PEELS e.g. it’s more holistic than reductionist as it considers environment and genetics by referring to the diathesis stress model - PEELS e.g. Depression is not age specific and so data triangulation should be conducted with an older sample, or the same sample, to see whether the vulnerability of the gene for depression lasts later on into life. Study 2: Chiao and Blizinsky - Introducing sentence: However, unlike the last study just done in one culture, the following research was conducted crossculturally and found that the gene may not contribute towards the onset of depression - Aim, procedure, findings and conclusion (as detailed as on slide 36) - Critical thinking: offer the alternative explanations on slide 37. Could include one more PEEL if you want Discussion: Lots of potential points to use here depending on time - Could include an additional piece of research support from slides 38, 44, 45 - The cortisol point on slide 40-41 is a REALLY good one to make, so I would try to prioritise this.
