Chapter One The Major Issues

Biological Psychology “study of the physiological, evolutionary, and developmental mechanisms of behavior and experience”

The Major Issues The Mind-Brain Relationship Biological Explanations of Behavior Four categories physiological-relates a behavior to the activity of the brain and other organs ontogenetic-describes the development of the structure or behavior evolutionary-examines a structure or a behavior in terms of evolutionary history functional-describes why a structure or behavior evolved as it did

The Major Issues The Mind-Brain Relationship The Brain and Conscious Experience Dualism defined-the belief that mind and body are different kinds of substances, that exist independently but somehow interact DesCartes-proposed that mind and brain interact in the pineal gland

The Major Issues The Mind-Brain Relationship The Brain and Conscious Experience Monism defined-the belief that the universe consists of only one kind of existence Forms of Monism materialism-the view that everything that exists is material or physical mentalism-the view that only the mind really exists identity position-the view that mental processes are the same thing as certain kinds of brain processes, but described in different terms

The Major Issues The Mind-Brain Relationship Discussions of Consciousness David Chalmers-proposed distinguishing easy problems from hard problems easy problems pertain to many phenomena to which we apply the term consciousness Ex: the difference between wakefulness and sleep, and the mechanisms that enable us to focus our attention hard problem-the question of why and how any kind of brain activity is associated with consciousness

Nature or Nurture The Genetics of Behavior Chromosome Structure genes-units of heredity that maintain their structural identity from one generation to another chromosomes-strands of genes deoxyribonucleic acid-DNA-when it exists as a double strand in a helix, it makes up a chromosome; when it exists in a single strand, it serves as a template for the synthesis of RNA ribonucleic acid (RNA)-single strand chemical that can serve as a template for the synthesis of proteins enzymes-biological catalysts that regulate chemical reactions in the body

Figure 1.6 How DNA controls development of the 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.

Nature or Nurture Mendelian Genetics Cont’d Patterns of Inheritance homozygous-having an identical pair of genes on two chromosomes heterozygous-having an unmatched pair of genes on two chromosomes dominant gene-expressed in either the homozygous or heterozygous condition (ex: Bb or BB will be expressed as “brown eyes”) recessive gene-only expressed in the homozygous condition (ex: bb is the only condition where “blue eyes” will be expressed)

Figure 1.7 Four equally likely 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).

Nature and Nurture Mendelian Genetics Cont’d Patterns of Inheritance Linkage and Crossing Over Occurs when the inheritance of one gene is linked to inheritance of another gene Occurs when a pair of chromosomes break apart and reconnect exchanging parts of each chromosome Sex-Linked Genes genes that are located on the sex chromosomes an X-linked recessive gene will always be expressed in a male while a female will only express the gene if both of her X chromosomes carry the recessive gene

Nature and Nurture Mendelian Genetics Cont’d Patterns of Inheritance Sex-Limited Genes present in both sexes but is expressed in only one sex, or has a much stronger effect in one sex than the other the genes do not need to be on the sex chromosomes these genes are expressed only after activation by sex hormones Sources of Variation Recombination-some genes from one parent and some from the other, that combine to yield characteristics not found in either parent Mutation-a random change in a single gene

Nature and Nurture Heritability defined-an estimate of how much of the variance in some characteristic within a population is due to heredity Ranges from 0 to 1 If 0 then hereditary differences account for none of the observed variations in that characteristic If 1 then hereditary differences account for all of the observed variations in that characteristic

Nature and Nurture Cont’d How Heritability is Determined Compare similarities in monozygotic twins versus dizygotic twins Compare adopted children and their biological and adoptive parents Can heritability be modified? PKU prevention as an example

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 more similar prenatal environments as well as more similar heredities.

The Evolution of Behavior Evolution Defined-change over generations in the frequencies of various genes in a population How it occurs-Characteristics that lend themselves to survival assist an individual in surviving to reproductive age, therefore these “survival” genes are passed on to the next generation Artificial Selection Choosing individuals with a desired trait and making them the parents of the next generation Video

Common Misunderstandings About Evolution Does the use or disuse of some structure or behavior cause an evolutionary increase or decrease in that feature? Have humans stopped evolving? Does “evolution” mean “improvement”? Does evolution act to benefit the individual or the species?

Sociobiology Defined-studies the issues that concern the evolution of social behavior It emphasizes functional explanations Criticisms of the field Functional explanations are often speculative Sociobiological explanations sometimes imply that human behavior has evolved to be as it is, and therefore it should stay that

Use of Animals in Research Reasons for Animal Research The underlying mechanisms of behavior are similar across species and sometimes are easier to study in a nonhuman species We are interested in animals for their own sake What we learn about animals sheds light on human evolution Certain experiments cannot use human subjects because of legal or ethical restrictions

Use of Animals in Research The Ethical Debate The range of opposition minimalists-agree that some animal research is acceptable, but wish to minimize it abolitionists-want all research on animals to stop

Prospects for Further Study Researchers Associated with Biological psychology Behavioral neuroscience-investigates how the function of the brain and other organs influences behavior Neuroscience-studies anatomy, physiology and biochemistry of the nervous system Neuropsychologist-conducts behavioral test to determine recovery and deterioration after brain damage

Prospects for Further Study Researchers associated with Biological Psychology Cont’d Psychophysiologist-measures heart rate, breathing rate, brain waves and other body processes that change as a function of what someone is doing Comparative psychologist-compares the behaviors of different species and tries to relate them to evolutionary histories and ecological niches Sociobiologist-relates behaviors, especially social behaviors, to the function they have served, and therefore the presumed selective pressures that caused them to evolve

Prospects for Further Study Medical Doctors 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