Biological Psychology, 8th Edition Chapter 1

James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 1 of 26 Chapter One The Major Issues James W. Kalat Biological Psychology, 8th Edition Chapter 1...

James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 1 of 26 Chapter One The Major Issues James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 2 of 26 Biological Psychology Study of the physiological, evolutionary, and developmental mechanisms of behavior and experience – emphasis on the study of areas and sub-areas of the brain – brain area’s function depends on communication among neurons, the “building blocks of behavior” – neuron activity somehow produces behavior and experience James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 3 of 26 Figure 1.1 Figure 1.1 A dorsal view (from above) and a ventral view (from below) of the human brain. The brain has an enormous number of divisions and subareas; the labels point to a few of the main ones that are visible from outside. James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 4 of 26 Biological Explanations of Behavior Physiological: relates a behavior to the activity of the brain and other organs (area of brain enables bird to sing) Ontogenetic: describes the development of the structure or behavior (why genes and environment both necessary for bird to sing) Evolutionary: examines a structure or a behavior in terms of evolutionary history (two different species of birds with similar songs have same ancestor) Functional: describes why a structure or behavior evolved as it did (singing improves bird’s chances of mating) James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 5 of 26 Mind-Body Problem Dualism: mind and body are different kinds of substances, that exist independently but somehow interact – René Descartes proposed that mind and brain interact in the pineal gland Monism: there is only one kind of existence – materialism: everything is material or physical – mentalism: only the mind exists – identity: mental processes are the same thing as certain kinds of brain processes, but described in different terms (e.g., fear is the same as the accompanying pattern of neural activity in the brain) James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 6 of 26 Mind-Body Problem cont. What is consciousness and how is it produced? Hard problem: the question of why and how any kind of brain activity is associated with consciousness – Chalmers (1995): consciousness is a fundamental property of matter and cannot be reduced further Easy problems: determining the difference between wakefulness and sleep, or identifying brain mechanisms that enable us to focus our attention – Dennet (1991, 1996): When we answer all of the easy problems, the hard problem will go away James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 7 of 26 Mind-Body Problem cont. Research may not solve problem soon because consciousness is not directly observable – I know that I am conscious but I can only infer that you have conscious experience – solipsism: the belief that only I exist Where and when does consciousness occur? – do all animals have conscious experiences? plants? rocks? – when does the human embryo experience consciousness? – could we build a robot that experiences consciousness? James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 8 of 26 Genetics of Behavior Mendel (19th century): inheritance occurs through genes – chromosomes are strands of genes, normally in pairs – genes are units of heredity that maintain their structural identity across generations – a genotype is an expression of a gene pair (e.g., BB, Bb, or bb) Deoxyribonucleic acid (DNA): – when DNA exists as a double strand in a helix, it makes up a chromosome – when DNA exists in a single strand, it serves as a template for the synthesis of RNA James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 9 of 26 Figure 1.6 Figure 1.6 How DNA controls the development of an organism. The sequence of bases along a strand of DNA determines the order of bases along a strand of RNA; RNA in turn controls the sequence of amino acids in a protein molecule. James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 10 of 26 Genetics of Behavior cont. Genotype expression (B=brown eyes; b=blue eyes) – homozygous: having an identical pair of genes on two chromosomes (BB or bb) – heterozygous: having an unmatched pair of genes on two chromosomes (Bb) – dominant gene: expressed in either the homozygous or heterozygous condition (Bb or BB will be expressed as brown eyes) – recessive gene: only expressed in the homozygous condition (bb is the only condition where blue eyes will be expressed) James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 11 of 26 Figure 1.7 Figure 1.7 Four possible outcomes of a mating between parents who are heterozygous for a given gene (Tt). A child in this family has a 25% chance of being homozygous for the dominant gene (TT), a 25% chance of being homozygous for the recessive gene (tt), and a 50% chance of being heterozygous (Tt). James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 12 of 26 Genetics of Behavior cont. When genes are close together on the same chromosome they are usually inherited together, e.g., BC or bc – “crossing over” occurs during reproduction when a pair of chromosomes exchange parts with each other, e.g., BC and bc become Bc and bC Sex-linked genes on X and Y chromosomes – male (XY) has only one X chromosome and will always express X-linked recessive genes (8% have red-green color blindness) – female (XX) will express a recessive gene only if it occurs on both of her X chromosomes (1% have color blindness) James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 13 of 26 Genetics of Behavior cont. Sex-limited genes – present in both sexes but effect is limited or almost limited to one sex (chest hair, breast size) – genes expressed only after activation by sex hormones Sources of variation – recombination: some genes from two parents combine to yield characteristics not found in either parent – mutation: a random change in a single gene – crossing over creates unique characteristics not found in either parent James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 14 of 26 Genetics of Behavior cont. Heritability – an estimate of how much of the variance in a population characteristic is due to heredity (ranges from 0 to 1) – if 0, heredity accounts for none of the observed variations in that characteristic (e.g., in a population with similar genes, most differences are due to environment) – if 1, heredity accounts for all of the variations in that characteristic (e.g., in identical environments most differences are due to genes) – if 0.5, both components contribute James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 15 of 26 Genetics of Behavior cont. How heritability is determined – compare similarities in monozygotic twins versus dizygotic twins – compare adopted children with their biological and adoptive parents – findings support high heritability in many areas but we may underestimate the effect of environment and interaction between geneotype and environment James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 16 of 26 Genetics of Behavior cont. Can heritability be modified? – PKU, caused by genetic inability to metabolize phenylalanine, can be minimized with proper diet James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 17 of 26 Figure 1.8 Figure 1.8 Prenatal development of monozygotic and dizygotic twins. In most cases, monozygotic (identical) twins develop in a single placenta and have the same blood supply. Dizygotic (fraternal) twins develop in separate placentas. Therefore, monozygotic twins have the sane prenatal environment as well as the same genetic inheritance, and dizygotic twins differ in both respects. James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 18 of 26 Evolution of Behavior Change over generations in the frequencies of various genes in a population Change occurs through mutations, recombinations and any new genes that are successfully reproduced Artificial selection limits reproduction to animals that possess a desired trait, ensuring its survival James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 19 of 26 Misunderstandings about Evolution “Lamarckian evolution” is mistaken belief that we acquire characteristics through use and lose them through disuse. If “survival of fittest” no longer applies, has evolution stopped? – no, reproduction, not survival is key Does evolution mean improvement? – maybe; your genes got you here but they may not be advantageous tomorrow Does evolution act to benefit the individual or the species? – neither; it acts to spread the genes James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 20 of 26 Sociobiology/Evolutionary Psychology Seeks functional explanations for why a behavior is useful and is favored by natural selection – why some animals have better color or peripheral vision – why we cycle through stages of sleep – why mammals and birds use most of their energy to stay warm – why different species have different eating habits – why people die at different rates – why more men than women enjoy casual sex with multiple partners James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 21 of 26 Sociobiology/Evolutionary Psychology cont How does sociobiology explain altruistic behavior? – a gene that encourages altruism would help others survive to reproduce – humans exhibit altruism but uncommon in non-humans – reciprocal altruism and kin selection may help spread gene Sociobiology can be criticized when practitioners assume that a behavior is adaptive and then propose an explanation without testing it James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 22 of 26 Reasons for Animal Research Underlying mechanisms of behavior are similar across species and sometimes a nonhuman species is easier to study We are interested in animals for their own sake Learning about animals sheds light on human evolution Legal or ethical restrictions prevent the use of human participants in certain experiments James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 23 of 26 Figure 1.12 Figure 1.12 Brains of several species. The general plan and organization of the brain are similar for all mammals, even though brain size varies from species to species. James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 24 of 26 The Ethical Debate on Animal Research Some experiments subject animals to brain damage, electrode implantation, injections for drugs or hormones Minimalists agree that some animal research is acceptable, but wish to minimize it Abolitionists want all research on animals to stop Principles of moderation and compromise are now the legal standard in the US James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 25 of 26 Careers in Biological Psychology for Psychologists (PhDs) Behavioral neuroscientist: investigates how functioning of the brain and other organisms affect behavior Neuroscientist: studies anatomy, biochemistry, and physiology of the nervous system Neuropsychologist: conducts behavioral tests to determine what brain damaged people can and cannot do Psychophysiologist: measures heart rate, breathing rate brain waves, and other body processes that change as a function of people’s activities and information processing James W. Kalat Biological Psychology, 8th Edition Chapter 1: The Major Issues 26 of 26 Careers in Biological Psychology for Physicians (MDs) Neurologist: treats people with brain damage or diseases of the brain Neurosurgeon: performs brain surgery Psychiatrist: helps people with emotional distress or troublesome behaviors, sometimes using drugs or other medical procedures