01_Handout.pdf

AS2308 INTRODUCTION TO PHYSIOLOGICAL/BIOLOGICAL PSYCHOLOGY From the earliest historical times, human beings always believed that such a thing as mind, soul, or spirit exists. The question...

AS2308 INTRODUCTION TO PHYSIOLOGICAL/BIOLOGICAL PSYCHOLOGY From the earliest historical times, human beings always believed that such a thing as mind, soul, or spirit exists. The question about the true nature of the human mind has always been asked. Is the mind situated in our brain? Because some ancient cultures believed that the heart is the seat of thought and emotions. Does our mind control the nervous system, or is it a part of it? Is it a physical entity? Or intangible, like the soul? Mind–body or mind–brain problem: What is the relationship between the mind and brain activity? Biopsychology and Neuroscience Physiological Psychology  Physiological Psychology was born by combining the experimental methods of psychology and physiology, applying them to answer questions concerning psychology.  Physiological Psychology studies the human mind through an empirical and practical approach. It believes that to understand human perception, thinking, and behavior, the activity of the nervous system and the workings of the body should be understood first.  Physiological psychologist – A scientist who studies the physiology of behavior: how the nervous system and the rest of the body control behavior and other processes such as sensory, sleep, emotional behavior, ingestive behavior, aggressive behavior, sexual behavior, parental behavior, and learning and memory.  Rene Descartes – was the first to suggest a link between the human mind and the anatomical brain.  A split‐brain operation separating the two cerebral hemispheres suggests that consciousness or awareness is made possible by the brain activities in the left hemisphere, particularly speech. A person who underwent a split‐brain operation cannot verbally acknowledge the presence of stimuli if presented to the right hemisphere. However, movements from the left side of the body confirm the presence of the stimuli through movement. It shows that the mind or consciousness is not 100% aware and in control of all the brain activities. Neuroscience  Physiological psychology falls under the broader field of neuroscience, which studies everything about the nervous system – anatomy, chemistry, physiology, development, and functioning.  In comparison with biological psychology, neuroscience studies the same thing but with more emphasis on chemistry and anatomy.  Neurology is the branch of medicine that studies diseases of the nervous system. As one of the symptoms of nervous system diseases is changes in behavior, neurologists also study the behavior of people with brain damage. Biological psychology  Biological psychology – relates biology to psychology; “it is the study of physiological, evolutionary, and developmental mechanisms of human behavior and experience.”  It posits that behavior is a product of the evolution of the brain mechanisms and other organs related to it; for example, yawning is a behavior that does not have a known purpose but is hypothesized to be a product of evolution and biology 01 Handout *Property of STI  [email protected] Page 1 of 6  AS2308  Another example: doves and pigeons drink with their heads down compared to other birds. Physiology explains this through nerves and throat muscles, evolution explains this through heredity and genes, while biological psychology explains this through the interaction of physiology, evolution, and other factors  Biological explanations of behavior are categorized into four: o Physiological explanation – as mentioned earlier, it connects behavior to brain activity and other organs related to it; Example – testosterone affects a certain brain area of a songbird, which enables male songbirds to sing o Ontogenetic explanation connects behavior with the influence of genes, nutrition, experiences, and their interactions. For example, for a male songbird to learn how to sing, it should have a particular set of genes and learn from adult male songbirds in a critical early development period. o Evolutionary explanation – connects the behavior with its history of development and structure. Example – Some pairs of species of songbirds have similar songs, suggesting that they evolved from one ancestor. o Functional explanation – connects the behavior to the reasons as to why it evolved as it did; Example – songbirds have evolved tendencies to sing to increase chances of mating. Genetics and Behavior Mendelian Genetics  Before, scientists used to think that inheritance was just a blend of the sperm and egg, like combining two paint colors. Gregor Mendel showed that inheritance happens through genes, or units of heredity, that maintain their identity from one generation to the next. It contains the double‐stranded molecule called deoxyribonucleic acid (DNA), which is the blueprint for the synthesis of ribonucleic acid (RNA) and the blueprint for the synthesis of protein molecules, ultimately determining the development of an organism.  Proteins can be part of the body's structure or serve as enzymes, which trigger the regulation of chemical reactions in the body).  Chromosomes ‐ strands of pairs of genes. Only one chromosome does not come in a pair ‐ the male sex chromosome.  Homozygous ‐ when one inherits the same version or alleles of a gene from each parent and thus has an identical pair of genes on two chromosomes. For example, having black hair genes on all chromosomes.  Heterozygous ‐ when one inherits different versions or alleles of a gene from each parent, thus having an unmatched pair of genes on two chromosomes. For example, having one black hair gene on one chromosome and a brown hair gene on the other.  Specific genes can be identified as dominant or recessive: o Dominant genes show a strong effect in either homozygous or heterozygous genes; a carrier for both a dominant black hair gene and a recessive brown hair gene will have black hair; a carrier for two dominant black hair genes will have a black hair o Recessive genes manifest their effects only in homozygous genes; a carrier of two recessive brown hair genes will have brown hair.  Nuances in gene expression: 01 Handout *Property of STI  [email protected] Page 2 of 6  AS2308  Characteristics are often a product of contributions from many different genes; for example, variations in eye color are a product of the contribution of 10 genes. Partial expression of a gene is also possible. Sex-Linked and Sex-Limited Genes  Sex‐linked genes are located on sex chromosomes, while all other chromosomes are called autosomal chromosomes, having also autosomal genes.  A female mammal has two X chromosomes; a male has one X and one Y chromosome.  The Y chromosome carries the gene that causes a person to develop as a male.  Sex‐linked recessive genes have their effects only in the absence of the dominant gene.  Sex‐limited genes: Genes present in both sexes but only manifest as characteristics in one sex and will only manifest if activated by sex hormones.For example, genes for chest hair in men and breast size in women. Genetic Changes  Genes change in several ways: o Mutation: a heritable change in a DNA molecule  Mutations are rarely beneficial. One rare example: the FOXP2 gene, which facilitates language development.  Other types of mutations: duplication or deletion, microduplication or microdeletion. o Epigenetics: changes in gene expression without modification of the DNA sequence. Such change in gene expression can be caused by any experience ‐ maternal deprivation, cocaine exposure, new learning, or whatever. Any experience brings new proteins into a cell or alters the chemical environment in other ways. In short, experience has an impact on a molecular level. Heredity and Environment  Differences in behavior depend on the mixed influence of many genes and environmental influences.  Heritability estimates how much of the variance in some characteristics is due to heredity.  Heritability in humans is studied in three ways: by comparing monozygotic (identical) twins, dizygotic (fraternal) twins, and adopted children and their biological parents.  Most behaviors are found to have high heritability. Still, environmental factors can modify highly heritable and even those traits. Also, the degree of manifestation of a gene may be affected by environmental factors. For example, Phenylketonuria or PKU, a genetic inability to metabolize 01 Handout *Property of STI  [email protected] Page 3 of 6  AS2308 phenylalanine leading to impaired brain development, is a hereditary condition that can be prevented from emerging through a low‐phenylalanine diet.  Genes affect behavior through the proteins they produce and their influence on specific body systems. Evolution of Behavior  Evolution: Any change of frequencies of genes in a population over a generation. o How do species evolve?  Offspring generally resemble their parents, but new inheritable variations in the gene pool can occur because of mutations and recombinations.  Natural selection: Genes that are associated with survival and success in reproduction becomes more prevalent in the next generations o Artificial selection: Breeding animals for desirable individual characteristics, which causes changes in various genetic frequencies in a population  Misconceptions in evolution: o Misconception: Lamarckian evolution: Use or disuse of some characteristics or behavior causes will determine if it will get extinct or passed on;  Clarification: There is no empirical basis for this o Misconception: Humans are no longer evolving because of modern medicine and prosperity.  Clarification: This is also untrue ‐ humans are still evolving as long as genes spread in a population. o Misconception: Evolution improves the fitness of the population.  Clarification: Genes fit in a particular environment and may be unfit for another. Features that are adaptive right now might not be adaptive in the future. o Misconception: Evolution acts to benefit the individual or the species.  Clarification: Evolution benefits the genes.  Altruistic behavior: Behaviors that benefit others rather than the individual committing the behavior. It is in contrast to the belief that genes evolve for their benefit. If altruistic genes exist, they may spread through reciprocal altruism (the notion that animals help those who will help them in return) or kin selection (selection in favor of a gene because it benefits the animal’s relatives).  Evolutionary psychology is the study of the relationship between social behavior and evolutionary theory; evolutionary psychologists focus on how a behavior may be useful to a population and why natural selection favors it. The Use of Animals in Research A. Four reasons why biological psychologists study animal behavior: 1. The underlying mechanisms of behavior are similar across species (especially mammalian) and are often easier to study in nonhuman species. 01 Handout *Property of STI  [email protected] Page 4 of 6  AS2308 2. We are interested in animals for their own sake. 3. What scientists learn about animals sheds light on human evolution. 4. Specific experiments cannot use human subjects because of legal or ethical restrictions. B. The Ethical Debate 1. Opposition to animal research ranges considerably in degree. “Minimalists” believe some animal research is acceptable but wish it to be minimized and regulated. “Abolitionists” believe that all animals deserve the same rights as human beings and that using animal subjects is the moral equivalent to slavery and murder. 2. Researchers in biological psychology realize that using animals in experiments is necessary for acquiring knowledge about behavior but may indeed be painful to their subjects. Therefore, investigators often look for compromises when conducting animal research to reduce the suffering of animals. 3. References Elias, Lorin J. and Saucier, Deborah M. (2006). Neuropsychology: Clinical and Experimental Foundations. Pearson. Kalat, J. (2008). Reproductive behaviors. In J. Kalat (Eds.), Biological Psychology (10th ed., pp. 27-47). Wadsworth, Cengage Learning. Kreitler, S. (2018). The Mind‐Body Problem: The Perspective of Psychology. Open Journal of Philosophy, 8, 60‐75. https://doi.org/10.4236/ojpp.2018.81006 Koenigshofer. K.(n.d.) Human Evolution. LibreText: Social Science. Retrieved from: https://socialsci.libretexts.org/Bookshelves/Psychology/Biological_Psychology/Biopsychology_(OERI)_‐ _DRAFT_for_Review/03%3A_Evolution_Genes_and_Behavior/3.03%3A_Human_Evolution Koenigshofer, K. (2010). Mind Design: The Adaptive Organization of Human Nature, Minds, and Behavior. Pearson Educational Solutions, Boston. Morrison, A. R. (2009). An odyssey with animals: A veterinarian’s reflections on the animal rights & welfare debate. New York: Oxford University Press. Pinel, J. P. J. & Barnes, S. J. (2022). Biopsychology (11th Ed). Pearson. Wickens, Andrew P. (2021). Introduction to Biopsychology. Sage Publishing. Wood, B. (2010). Reconstructing human evolution: Achievements, 01 Handout *Property of STI  [email protected] Page 5 of 6  AS2308 challenges, and opportunities. Proceedings of the National Academy of Sciences, 107 (supplement_2), 8902‐ 8909. 01 Handout *Property of STI  [email protected] Page 6 of 6