Psychology and the Scientific Method PDF

PSYCHOLOGY AND THE SCIENTIFIC METHOD What is Psychology?  The Scientific Method § A way of learning about the world through collecting observations § Developing theories to explain the observations § Using the theories to make predictions about future events  The Scientific...

PSYCHOLOGY AND THE SCIENTIFIC METHOD What is Psychology?  The Scientific Method § A way of learning about the world through collecting observations § Developing theories to explain the observations § Using the theories to make predictions about future events  The Scientific Method § Hypothesis: a testable prediction about processes that can be observed and measured § Do NOT prove hypotheses § Must be falsifiable § ‘All swans are white’ vs ‘all men are mortal’ § Must be stated in precise and relevant terms The Scientific Method § Theory: an explanation for a broad range of observations that also generates new hypotheses and integrates numerous findings into a coherent whole § Built from hypotheses § Must be falsifiable § Can be updated with new information The Scientific Method § Theories § NOT the same as opinions § All theories are NOT equally plausible § Validity NOT determined by number of people who believe it to be true THE IMPORTANCE OF SCIENTIFIC LITERACY Scientific Literacy Critical thinking: exercising curiosity and skepticism when evaluating the claims of others, and with our own assumptions and beliefs Increasingly important as we sort through the barrage of information in the digital age Scientific Literacy For psychologists, critical thinking means: § Applying the scientific method § Examining assumptions and biases, both of others and our own § Considering alternative viewpoints § Tolerating ambiguity when evidence is inconclusive  The Principle of Parsimony Principle of parsimony: the simplest of all competing explanations of a phenomenon should be the one we accept  Explaining the Paranormal Should we accept the paranormal…or use more parsimonious explanations with a basis in what we know about the physical and natural world Abductions, ghost sightings, and other paranormal activity explained by: Alien movies Fantasies and false memories Sleep paralysis and hallucinations  HOW PSYCHOLOGY BECAME A SCIENCE: EARLY INFLUENCES  Scientific Principles Scientific thought has two fundamental beliefs: § Empiricism: philosophical tenet that knowledge comes through experience § Determinism: the belief that all events are governed by lawful, cause-and- effect relationships Zeitgeist: refers to a general set of beliefs of a particular culture at a specific time in history – Delayed the science of psychology – Materialism: the belief that humans, and other living beings, are composed exclusively of physical matter  Influences from the Ancients Hippocrates (460-370 BCE) § Considered father of Western medicine Four ‘humours’ thought to contribute to our health and personality § Blood § Yellow bile § Black bile § Phlegm  Influences from the Ancients Aristotle (384-322 BCE) § Tabula Rasa – Man begins life with a blank slate § Para Psyche (‘about the mind’): First text in history of psychology Psyche: “the mind” is the source of all human behavior § No differentiation between mind and soul Ancient Greeks thought the brain cools the blood and plays no role in behavior § Memory stored in the heart Philosophical Influences René Descartes (1596-1650) § Proposed ‘Cartesian dualism’ as solution to the mind-body problem § Both a nonmaterial mind and a material body drive behavior Solution suffered from the ‘Problem of interactionism’ Tried to resolve ‘Problem of Interactionism’ via the pineal gland Influences from Physics Gustav Fechner (1801-1887) § ‘Psychophysics’ – the study of the relationship between the physical world and the mental representation of that world Influences from Physics Response Expansion Response Compression  Influences from Evolutionary Theory Charles Darwin (1809-1882) § Theory of evolution by natural selection § Variation of traits make some individuals more likely to survive and produce offspring § Over time, surviving traits become more common Influences from Evolutionary Theory Charles Darwin (1809-1882) § Evolution can also select for behaviours! § Emotional expressions Influences from Evolutionary Theory  HOW PSYCHOLOGY BECAME A SCIENCE: INFLUENCES FROM MEDICINE Influences from Medicine Brain localization: certain parts of the brain control specific mental abilities 1. Phrenology Franz Joseph Gall (1758- 1828) and Johann Spurzheim (1776-1832) § Brain consisted of 27 ‘organs’, each associated with a personality trait § Size of organ corresponded to development of trait Influences from Medicine Brain localization: certain parts of the brain control specific mental abilities 2. Brain injury Paul Broca § Identified brain region associated with speech production Carl Wernicke § Identified brain region associated with speech comprehension Influences from Medicine Franz Mesmer (1734-1815) § Believed magnets could redirect the flow of metallic fluids in the body to cure diseases § Directed fluids by ‘mesmerizing’ the patient with hand movements, inducing a trance § Phenomenon of inducing trances later renamed hypnosis  Influences from Medicine Sigmund Freud (1856-1939) § Psychoanalysis: a psychological approach that attempts to explain how behaviour and personality are influenced by unconscious processes Influences from Medicine Sigmund Freud (1856- 1939) Believed the unconscious mind guided our behaviours § Id: Instincts § Super-ego: Morality and critical thinking § Ego: Organized part that mediates between the desires of the Id and Super-ego Influences from Medicine Criticisms of Freud: Used subjective rather than scientific method Dismissed claims of sexual abuse as mere constructions of our unconscious mind Theory suggested a lack of free will Influences from Medicine Contributions of Freud: Introduced the potential for unconscious mental processes Medical model: use of medical ideas to treat psychological disorders Incorporated evolutionary thinking by acknowledging physiological needs and urges Emphasized that experiences during development influence adult behaviour  HOW PSYCHOLOGY BECAME A SCIENCE: ESTABLISHING A SCIENCE The Influence of Social Sciences Sir Francis Galton (1822-1911) § Influenced by economics, sociology, and anthropology § Investigated nature and nurture relationships § The inquiry into how hereditary (nature) and environment (nurture) influence behaviour and mental processes § Believed heredity explained psychological differences The Influence of Social Sciences Sir Francis Galton (1822-1911) § Eminence: Combination of ability, morality, and achievement resulting from good genes § Beliefs led him to coin the term ‘eugenics’ and justify its use § Alternative explanations??? Primary contributions of Galton: § Initiated debate about nature and nurture § Promoted use of statistical methods to quantify psychological traits  The Beginnings of Psychology Wilhelm Wundt (1832-1920) § Setup first laboratory dedicated to studying human behaviour § Used introspection: a process of ‘looking within’ to describe psychological sensations Introspection and Structuralism Structuralism: analyzing conscious experience by breaking it down into basic elements and to understand how these elements work together Red Shiny Juicy Apple Round Tart The Study of Thought Reaction time methods: participants asked to react to the sound of metal balls hitting one another § Participants reacted after ~1/8 of a second § Mental activity not instantaneous  Structuralism: The Beginnings of Psychology Edward Titchener (1867-1927) § Adopted Wundt’s method of introspection, though criticism of approach was growing § Described mental experiences as composed of ‘elements’ much like the elements of the periodic table used in the physical sciences § Different combinations of elements responsible for more complex experiences Functionalism: The Beginnings of Psychology William James (1842-1910) § Wrote first modern textbook in psychology, The Principles of Psychology § Influenced by Darwin’s evolutionary principles Proposed functionalism: the study of the purpose and function of behaviour and conscious experience The Discovery of Conditioning Edwin Twitmyer (1873-1943) Discovered conditioned reflexes The Discovery of Conditioning Ivan Pavlov (1849-1936) § Trained dogs to salivate in response to a metronome § Won Nobel Prize for discovering Classical Conditioning § A learning process that occurs when two stimuli are repeatedly paired  HOW PSYCHOLOGY BECAME A SCIENCE: BEHAVIOURISM The Rise of Behaviourism Ivan Pavlov (1849-1936) § Study of conditioning soon became the focus of: § Behaviourism: The study of observable behaviour, with little or no reference to mental events or instincts as possible influences on behaviour  The Rise of Behaviourism John B. Watson (1878-1958) § Rise of behaviourism in North America § Only observable changes in behaviour and the environment should be studied scientifically All behaviour could be explained by conditioning  The Rise of Behaviourism John B. Watson (1878-1958) § Revolutionized the principles of marketing § Developed ads that formed associations between a product and a desired feeling § Methods still used by advertisers The Rise of Behaviourism B.F. Skinner (1904-1990) § Believed in fundamental rules of learning shared among all animals § Operant conditioning: strengthening or weakening a behaviour by reward and punishment § Theory left little room for free will  HOW PSYCHOLOGY BECAME A SCIENCE: BEYOND BEHAVIOURISM Humanistic Psychology Emerges Humanistic Psychology: focuses on the unique aspects of each individual human, each person’s freedom to act, his or her rational thought, and the belief that humans are fundamentally different from animals Carl Rogers Abraham Maslow (1902-1987) (1908-1970) Focused on § Positive aspects of psychology § The meaning of experience § Self-actualization The Brain and Behaviour Karl Lashley (1890-1958) § Tried to locate the ‘engram’ Non-localization § Exact location of damage not important Principle of mass action § Size of damage corresponds with impairment  The Brain and Behaviour Donald Hebb (1904-1985) § Hebb’s Law: “Cells that fire together, wire together” Wilder Penfield (1891-1976) § Electrically stimulated brains of patients under local anesthetic § Mapped sensory and motor cortices  HOW PSYCHOLOGY BECAME A SCIENCE: THE COGNITIVE REVOLUTION The Cognitive Revolution Hermann Ebbinghaus (1850-1909) § Forgetting curves Frederick Bartlett (1886-1969) § Memory is an interpretive process The Cognitive Revolution Gestalt Psychology § Emphasized the need to focus on the whole of perception and experience, rather than its parts § “The whole is greater than the sum of its parts” The Cognitive Revolution Cognitive Psychology: Modern perspective that focuses on mental processes, such as memory, thinking, and language  Social and Personal Psychology Mingling of cognitive psychologists with behaviourists and sociologists after WW2 led to the emergence of Social and Personality Psychology Kurt Lewin (1890-1947) § Founder of modern social psychology § Behaviour is a function of individual and environment