IB syllabus says: Genetics & Behavior Key principle demonstrated: patterns of behavior can be inherited

IB syllabus says: Genetics & Behavior: A focus on ethics Key principle demonstrated: patterns of behavior can be inherited

In addition to these issues we also need to think about the wider ethical implications of what the findings of studies are, and how these are interpreted Activity: Write some detail on each of these

IB syllabus says: Genetics & Behavior Key principle demonstrated: patterns of behavior can be inherited

Lesson Objectives Genetics: gain an overview of what chromosomes & DNA are Examine what behavioral genetic studies that tell us about the extent to which genes influence behavior twin studies of eating disorders (anorexia & bulimia) & adoption studies of schizophrenia Examine the role of genes in attachment and imprinting Develop your knowledge and understanding of Evolutionary explanations of behavior Consider ethical considerations in research into genetic influences on behavior

Why study genes? Our brain, CNS and endocrine system keep us aware of what is happening outside and inside our bodies They enable use to think, use language and solve problems – so they guide our behavior To understand why the brain, CNS and endocrine system function the way they do, we need to look at our genetic heritage, as individuals (behavior genetics) and as members of the human species (evolutionary psychology)

Is intelligence inherited? Nature Vs. Nurture What do you think? ……………………………………………………… ……………………………………………………… ……………………………………………………… ……………………………………………………… ……………………………………………………… ……………………………………………………… ……………………………………………… Definition of Intelligence: The minds capacity to reason, to plan, to solve problems, to think abstractly, to comprehend ideas, to use language, and to learn.

Is intelligence inherited? Nature Vs. Nurture The pendulum swings between nature and nurture. If you asked 10 people 25 years ago – ‘is intelligence inborn or is it innate’ Most people would say ‘no’ and answer that it is a result of ‘upbringing’ (Nurture) But now most people would probably say ‘heredity’ i.e. – intelligence is inborn or innate (Nature) The shift in popular opinion parallels changes in scientific thinking This is an artificial debate – because both clearly play a role – e.g Rosenzweig’s study of neural plasticity shows this There is still disagreement regarding the relative influence of heredity (nature) and environment (nurture) on our thoughts, abilities, personalities and behaviors

Genetics This is the study of how living things pass on traits from one generation to the next We are not clones of are parents, but some traits or characteristics appear generation after generation in predictable patterns Scientists named these basic units of inheritance genes – they play a role in determining out physical characteristics and behavior Today – we know a lot about genes and how they work – Genes are carried by threadlike bodies called chromosomes, found in the nucleus of all cells Humans have 23 pairs, peas have 7, monkeys have 27 The main ingredient of chromosomes is DNA – a complex molecule in a double helix pattern DNA carries the directions for a particular trait or a group of traits The human genome contains as many as many as 100,000 genes Definition of Traits: Physical properties or behavior

Behavior Genetics This area studies the role that genes play in individuals behavior Of course, genes don’t directly cause behavior. But they do affect the development and operation of the nervous system and endocrine system, which in turn, influence the likelihood that a particular behavior will occur in certain circumstances (Wahlsten, 1999) There is animal behavior genetics e.g. Mice are often used because they breed quickly and have relatively complex behavior patterns, in Strain studies close relatives are inbred to create animals which are genetically very similar, so this allows us to look at the impact of the environment on their Behavior What are the ethical issues? However, this cant be done with humans – so how can we found out about the role of genes in human behavior?

Human behavior genetics: Twin Studies Twin studies are often used by psychologist to look at the influence of heredity and environment Identical (monozygotic - MZ) twins develop from a single fertilized ovum so any differences between them must be due to environmental factors Fraternal (dizygotic - DZ) twins develop from two separate fertilized eggs and are no more similar genetically than brothers and sisters

Genetic explanation for eating disorders Genetic science has not been able to identify genes for specific behaviors, such as those associated with eating disorders So research examines whether eating disorders run in families APA (1994) has shown that there is a much higher prevalence of those diagnosed with an eating disorder in a family than in the general population However, this might be due to the environment that individuals grow up in – their behavior may be learnt from other family members Twin studies also provide evidence research with MZ twins (who share identical genes) and DZ twins (that are no more genetically alike than other siblings). Therefore – environmental factors can be eliminated to if there is a higher concordance rate of the disorder in MZ twins that DZ twins (concordance means that both twins have the same disorder).

Clinical characteristics of anorexia nervosa Background info

Clinical characteristics of anorexia nervosa Background info

Clinical characteristics of bulimia nervosa Background info

Normal or above normal weight Binge Eating Compensatory Behavior Physical effects of purging Body perception Mood disturbance Awareness Clinical characteristics of bulimia nervosa

Normal or above normal weight Binge Eating Compensatory Behavior Physical effects of purging Body perception Mood disturbance Awareness Clinical characteristics of bulimia nervosa

Holland et al.’s (1984) Twin study of Anorexia Nervosa Aims Procedures Findings & Conclusions Evaluation

Ethical Issues?

Kendler et al.’s (1991) Twin study of Bulimia Nervosa Aims Procedures Findings & Conclusions Evaluation

Ethical Issues?

Human behavior genetics: Adoption Studies Adoption studies focus on children who were adopted at birth and brought up by parents not genetically related to them It can tell us about the heritability of mental illness

DSM IV (1994) – Diagnostic criteria for schizophrenia At least six months of disturbance + one month of active phase: two of the following for a period of one month. –1) delusions 2) hallucinations 3) disorganised speech 4) catatonic impaired movement. Substance abuse and general medical condition patients must be excluded Background info

Heston (1966) Adoption Study of schizophrenia Aim: To see if there is a genetic component to schizophrenia Procedure: Heston carried out a genetic epidemiology study of 47 participants whose mothers had schizophrenia and they had been adopted at birth and reared by normal parents Findings & Conclusion: Of the 47 people, 5 had schizophrenia, the direct risk of schizophrenia appears to increase in direct relation to the closeness of ones biological relationship to an individual with the disorder Evaluation: MECG? Ethical Issues?

Theories and studies of attachment in infants suggest that infants have a biological (genetic/inherited) drive to carry out this behavior Developmental Psychology

The biological basis of attachment Attachment “The formation of a strong, reciprocal emotional bond between an infant and a primary caregiver” This special bond can be seen to have an innate, biological basis

Bowlby (1969) Innate Programming and social releasers Attachment a characteristic selected and passed down because it helps individuals to possess it to survive. Inherited behaviour which helps individuals to survive Infants are born programmed to become attached= and adults to form attachment relationships with their children. Social Releasers are any behaviour that encourages a caregiver reaction ensure interaction takes place – smiling, crying, cooing or simply looking appealing – these elicit innate care giving responses in adults. These are innate in infants and other animals (as we can see from the pictures!)

Bowlby’s (1969) Critical periods Three important features of Bowlby’s (1969) attachment theory Infants and carers innately programmed to become attached. Attachment is a biological process, it takes place during a critical period of development or not at all Critical periods are a biological feature, if development does not take place in a set developmental period, then it may not take place at all. E.g. in the development of the human embryo, the arms begin to develop between days 24 and 26. Any interference at this stage would permanently damage the limbs development. Bowlby suggested that if a child does not form an attachment before the age of 2.5 years, then if would not be possible thereafter Bowlby’s work was influenced by earlier studies carried out with animals (Ethology)

Evidence from Lorenz (1937) Observation of Imprinting Aim: to observe the behaviour of newly hatched goslings Procedure: Lorenz divided eggs into two groups: some that hatched with their mother and some in an incubator – he found that the ones in the incubator began following him around (the first person they saw) Findings: Konrad Lorenz found that goslings are likely to imprint on the first moving object they see. There are short term (the young follow their mother) and long term effects (it is more likely the animal will be safe from predators) to this. Conclusions: There is an innate drive to ‘imprint’ which is inherited because it helps the goslings to survive. Evaluation: Generalisability?  Activity: Watch video of Lorenz Ethical Issues?

Genes & Genetics 1)Why is it important to study genes? 2) What influences how pendulum swings between nature and nurture? 3) What is behavior genetics the study of? 4) What is evolutionary psychology the study of? 5) What are genes? 6) How many chromosomes do humans have? (Where are they located? 7) What is the main ingredient of all chromosomes? Behavior genetics 8) Genes don’t directly cause behavior, but what do they do? 9) Give an example of animal behavior genetic research techniques? 10) What is the difference between identical and fraternal twins? 11) How can twin studies give us insight into genetic factors in the development of eating disorders? 12) Very briefly summarize the conclusions of Holland et al. (1984) and Kendler et al. (1991) study 13) What Heston’s (1966) adoption study tell us about the genetic basis to schizophrenia? Attachment Theory 14) What is attachment? 15) What does Bowlby propose attachment is? 16) Why is attachment innate? 17) What are critical periods? 18) What are social releasers? What is their function? 19) What is imprinting? What did Lorenz (1937) find with his goslings?