Lec-1-Issues-in-Biological-Psychology.pptx

The Major Issues in Biological Psychology Lesson 1  Topic Outline Biological Explanations of Behavior The Mind - Brain Relationship The Genetics of Behavior – Heredity and Environment – The Evolution of Behavior –...

The Major Issues in Biological Psychology Lesson 1  Topic Outline Biological Explanations of Behavior The Mind - Brain Relationship The Genetics of Behavior – Heredity and Environment – The Evolution of Behavior – Genes and Behavior  Biological Psychology Biological Psychology is the study of the physiological, evolutionary and developmental mechanisms of behavior and experience. biopsychology / psychobiology / physiological psychology / behavioral neuroscience The goal is to relate biology to issues of psychology  Biological Psychology Biological Psychology is not only a field of study, but also a point of view The proper way to understand behavior is in terms of how it evolved, and how the functioning of the brain and other organs controls behavior. Research Questions: what genes, prenatal environment, or other biological factors predispose people to psychological disorders? What enables humans to learn language easily?  Biological Explanations of Behavior 1. Physiological - relates the behavior to the activity of the brain and other organs. - e.g. low levels of dopamine cause a person to experience involuntary movements in the body 2. Ontogenetic - how a structure or behavior develops, incl. the influences of genes, nutrition, experiences & their interactions - ability to inhibit impulses develops gradually from infancy to adolescence  Biological Explanations of Behavior 3. Evolutionary - reconstructs the evolutionary history of a structure or behavior - goosebumps (hair erection) makes a frightened animal looks larger 4. Functional - describes why a structure or behavior evolved as it did - a camoufladged appearance makes an animal inconspicuous to predators thus aiding in its survival  The Mind - Brain Relationship Biological explanations of behavior raise the mind-brain problem: “What is the relationship between the mind and the brain?” Dualism - the belief that mind and body are different kinds of substances that exists independently Rene Descartes proposed that mind and brain interact at a single point in space, which he suggested was the pineal gland, the smallest unpaired structure found in the brain  The Mind - Brain Relationship Nearly all current philosophers and scientists reject the idea of dualism because because it conflicts with the law of conservation of matter and energy: matter can transform into energy or energy into matter, but neither one appears out of nothing, or disappears into nothing. Because matter alters its course only when matter or energy acts upon it, a mind that is not composed of matter or energy could not make anything happen. Monism - in contrast, is the belief that the universe consists of only one kind of substance  The Mind - Brain Relationship Various forms of monism are possible and grouped into the following categories: Materialism - everything that exists is material or physical. All psychological experiences can be explained in purely physical terms Mentalism - the view that only the mind really exists and that the physical world could not exists unless some mind were aware of it Identity Position - the view that mental processes and certain kinds of brain activities are the same thing. “Every mental experience is a brain activity” or “mental activity is what happens in the brain”  The Mind - Brain Relationship Can we be sure monism is correct? No. But it is the most reasonable working hypothesis. Stimulation of any brain area provokes an experience. One cannot have a mental activity without a brain activity. The hard problem is why the mind exists at all in a physical world. Why is there such a thing as consciousness, and how does it relate to brain activity? Accdg. to the identity position: brain activity does not cause consciousness any more than consciousness causes brain activity.  The Genetics of Behavior A gene is defined as a portion of a chromosome, which is composed of a double stranded molecule called deoxyribonucleic acid (DNA) A strand of DNA serves as a template for the synthesis of RNA which serves as a template for protein molecules. Some of these proteins form part of the structure of the body, while others regulate chemical reactions in the body.  The Genetics of Behavior homozygous - an identical pair of genes on the 2 chromosomes heterozygous - an unmatched pair of genes dominant genes - show strong effect in either homozygous or heterozygous conditions recessive genes - shows its effects only in homozygous conditions autosomal genes - are located on autosomal chromosomes sex linked genes - are located on sex chromosomes Y chromosome has genes for only 27 proteins while an X chromosome has genes for about 1500 proteins  Sex Linked and Sex Limited Genes An example of a human sex linked gene is the recessive gene for red- green color deficiency. Any man with this gene on his X chromosome experience this color deficiency because he has no other X chromosome. A woman can only be color deficient if she has that recessive gene on both of her X chromosomes. Sex limited genes (present in both sexes) are on autosomal chromosomes, but active mainly on one sex. Examples include genes that control amount of chest hair in men, breast size in women, amount of crowing in roosters and rate of egg production in hens.  Heredity and Environment Every behavior requires both heredity and environment. Take away either one, and nothing is possible. Do the observed differences among individuals depend more on differences in heredity or differences in environment? Many researchers utilized monozygotic and dizygotic twin studies to determine contributions of heredity and environment, as well as on adopted children. Biochemical methods have identified certain genes to be linked to conditions / behaviors including loneliness, neuroticism, TV watching, and social attitudes.  Heredity and Environment Heredity vs. prenatal influences Biological children of parents with criminal records are likely to have similar problems even when they are adopted by excellent parents. The biological parents gave them their genes and also their prenatal environment (poor diets, poor medical care, smoked, drank or used drugs)  Heredity and Environment Genes can also influence behavior indirectly by changing your environment (multiplier effect, Dickens & Flynn, 2001) genes / prenatal influence --> increase of some tendency environment that facilitates  How genes affect behavior The gene itself does not cause a condition, rather it produces a protein that under certain circumstances increases the probability of the condition. There are certain genes that control brain chemicals Genes also effect behavior indirectly, by changing the way others in the environment treat you. Eg. People deemed as attractive are more confident  The Evolution of Behavior Evolution is a change over generations in the frequencies of various genes in a population. It includes any change in gene frequency regardless of whether it helps / harms species in the long run. Any gene that is consistently associated with reproductive success will become more prevalent in later generations.  The Evolution of Behavior Artificial selection - a technique used by breeders when they choose individuals with desired traits and makes them parents of next generation Natural selection (Darwin, 1859): individuals more successful than others in finding food, escaping enemies, attracting mates, protecting their offspring, then their genes will become more prevalent in later generations  Evolutionary Psychology Evolutionary Psychology deals with how behaviors have evolved, especially social behaviors Is there a gene for altruistic behavior? Among non-humans, altruism toward non-relatives is rare in most species. (Eg. chimpanzees, crows) Altruisitic groups survive better than less cooperative ones (Bowles,2006) Reciprocal altruism - individuals help those who will return the favor (or extend help to others) Kin selection - in both humans and non-humans altruistic behavior is more common towards relatives than toward unrelated individuals  In sum, Biological Explanations of behavior: Most behavioral variations reflect physiological, ontogenetic, the combined influences of many evolutionary, functional genes and many environmental Biological explanations of behavior factors. do not assume that the individual Heritability is an estimate of the understands the purpose or amount of variation that is due to function of the behavior genetic variation as opposed to Dualism vs. Monism - try to explain environmental variation mind-brain relationship No one has found a way to answer the “hard problem:” why brain activity is related to mental experience at all.