Brain & Behaviour Session 2 PDF

BRAIN & BEHAVIOUR Introduction to Brain & Behaviour- Session 2 Likitha S Department of Psychology  Physiological Biological Evolutionary Mind and & explanations...

BRAIN & BEHAVIOUR Introduction to Brain & Behaviour- Session 2 Likitha S Department of Psychology  Physiological Biological Evolutionary Mind and & explanations & Functional Brain ontogenetic Biological explanation of behaviour Explanations of behavior often refer to intentional goals such as, “He did this because he was trying to...” or “She did that because she wanted to....” But frequently, we have no reason to assume any intentions Biological explanations physiological ontogenetic Evolutionary functional  A physiological explanation relates a behaviour to the activity of the brain and other organs. It deals with the machinery of the Physiological body—for example, the chemical reactions that enable hormones to influence brain activity and the routes by which brain activity ultimately controls muscle contractions  The term ontogenetic comes from Greek roots meaning “to be” and “origin” (or genesis). Thus, an ontogenetic explanation describes the development of a structure or a behaviour Ontogenetic It traces the influences of genes, nutrition, experiences, and their interactions in moulding behaviour. For example, the ability to inhibit an impulse develops gradually from infancy through the teenage years, reflecting the gradual maturation of the frontal parts of the brain Evolutionary An evolutionary explanation reconstructs the evolutionary history of a structure or behaviour For example, frightened people sometimes get “goose bumps”— erections of the hairs, especially on their arms and shoulders. Goose bumps are useless to humans because our shoulder and arm hairs are so short. In most other mammals, however, hair erection makes a frightened animal look larger and more intimidating (Figure 1.3). Thus, an evolutionary explanation of human goose bumps is that the behavior evolved in our remote ancestors and we inherited the mechanism  A functional explanation describes why a structure or behaviour evolved as it did. Within a small, isolated population, a gene can spread by accident through a process called genetic drift. (For example, a dominant male with many offspring spreads all his Functional genes, including neutral and harmful ones.) However, the larger the population, the less powerful is genetic drift. Thus, a gene that becomes common in a large population presumably has provided some advantage— at least in the past, though not necessarily in today’s environment How does evolutionary explanation differ from functional explanation  Perspectives of Brain and Behaviour ARISTOTLE AND DESCARTES AND DARWIN AND MENTALISM DUALISM MATERIALISM Aristotle and The concept, Mind controlling behaviour can be traced back to 2000 years ago to green- roman mythology. Mentalism: Aristotle’s account of behavior had no role for the brain, which Aristotle thought existed to cool the blood. To him, the nonmaterial psyche was responsible for human consciousness, perceptions, and emotions and for such processes as imagination, opinion, desire, pleasure, pain, memory, and reason The psyche was an entity independent of the body The word psyche was translated into English as mind, the Anglo-Saxon word for memory. The philosophical position that a person’s mind (psyche) is responsible for behavior is called mentalism. Mentalism has influenced modern behavioral science because many psychological terms that originated with Aristotle—consciousness, sensation, perception, attention, imagination, emotion, motivation, memory, and volition among them—survive today as descriptions of behavior mentalism: the view that only the mind really exists and that the physical world could not exist unless some mind were aware of it.  Descartes and dualism  Descartes did, however, develop a mechanical explanation for how the mind interacts with the body to produce movement, working through a small structure at the brain’s center, the pineal body (pineal gland). He concluded that the mind instructed the pineal body, which lies beside fluid-filled brain cavities called ventricles, to direct fluid from them through nerves and into muscles. When the fluid expanded the muscles, the body would move The inability of Descartes’s theory to explain how a nonmaterial mind and a physical brain might interact is called the mind– body problem.  Descartes’s thesis that the mind directed the body was a serious attempt to give the brain an understandable role in controlling behavior. This idea that behavior is controlled by two entities, a mind and a body, is known as dualism People who have a damaged pineal body or even no pineal body still display typical intelligent behavior. Today, we understand that the pineal gland’s role in behavior is relegated to biological rhythms. Experiments in Descartes’s time also showed that fluid is not pumped from the brain into muscles when they contract The inability of Descartes’s theory to explain how a nonmaterial mind and a physical brain might interact is called the mind–body problem.  The alternative to dualism is monism, the belief that the universe consists of only one kind of substance. Various forms of monism are possible, grouped into the following categories: Materialism Mentalism Identity position  By the mid-nineteenth century, another brain–behavior theory emerged. Materialism advanced the idea that the workings of the brain and the rest of the nervous system alone fully explain behavior. Darwin and It came to prominence when supported materialism by the evolutionary theory of Alfred Russel Wallace and Charles Darwin Evolution by natural Darwin proposed that Wallace and Darwin independently arrived Selection animals have traits in common because these at the same conclusion—the idea traits are passed from that all living things are parents to their related. offspring Both Darwin and The skeleton, muscles, Wallace were struck by and body parts of the myriad anatomical humans, monkeys, and and behavioral other mammals are characteristics common remarkably similar to so many species despite their diversity. THANK YOU Likitha S Department of Psychology [email protected]