History of Psychology

• Psychology is the scientific study of the mind and behaviour
• Philosophical debates within psychology include free will versus determinism, and nature versus nurture
• Psychiatry is a medical specialty focused on the study, diagnosis, treatment, and prevention of mental illness
• Social work is a profession dedicated to helping people deal with personal problems
• Psychology is a relatively new science, with most advances in the last 150 years
• The origins of psychology trace back to ancient Greece around 500BC as part of philosophy
• Philosophy is interested in understanding fundamental truths about humanity and our relationship with the world
• Socrates and Plato greatly influenced the field

Historical Figures

• Aristotle believed the heart was the most important organ, the root of intelligence, and the source of nerves
• Hippocrates believed the brain was the control centre of the body, responsible for thought and emotions
• Claudius Galen (130-210 CE) was a Greek physician and one of the first to research the brain in detail
• Galen's work established the link between the brain and body, and the brain's role in sensation
• Galen found that brain damage, not sensory organ damage, could cause loss of a particular sense

Free Will vs Determinism

• The free will vs determinism debate considers whether behavior results from forces beyond one's control or from one's own decisions
• Determinism: All behavior has a cause and is predictable, free will is an illusion and internal/external forces determine behaviour
• Free will: People are free to choose their behavior and are self-determined
• Determinists might argue external factors like poverty can cause someone to commit a crime

Nature vs Nurture

• The nature vs nurture debate considers whether behavior is inherited (genetic) or acquired (learned)
• Nature: Influenced by genetic inheritance and other biological factors
• Nurture: The influence of external factors like the environment
• Psychologists agree that both nature and nurture interact to influence people's behaviour

The Minnesota Study of Twins Reared Apart

• Thomas J. Bouchard and colleagues conducted this study in 1990
• It investigated the influence of environment and genetics on human characteristics and behaviours, including intelligence
• Compared data from over 100 pairs of twins and siblings, reared apart and together, in a cross-cultural study
• Identical and non-identical twins underwent over 50 hours of testing and interviews
• 70% of intelligence is heritable, meaning genes account for 70% of the variation in intelligence

The Mixed-Up Brothers of Bogotá

• The case study involved two pairs of identical twins mixed up after birth in 1988
• William and Jorge, and Wilber and Carlos, were accidentally switched in the hospital
• William was raised with Wilber in a rural area and Carlos was raised with Jorge in the city
• At 25, the brothers discovered they had been raised with their twin
• Similarities emerged between Carlos and Wilber and between Jorge and William due to their shared genetics

Twin Studies

• Twins who are reared apart demonstrate the extent to which traits are heritable because the environment in which they were raised was different
• Twins Jorge and Carlos were raised in Bogotá while William and Wilbur were raised in a rural village near Santander, Colombia

Psychologists, Psychiatrists and Social Workers

• Psychologists study the mind and behavior, treating mental, emotional, and behavioral disorders
• Training is obtained through university courses accredited by the Australian Psychology Accreditation Council (APAC)
• Psychologist need to be registered with the Psychology Board of Australia to practice in Australia
• Psychologists work in labs, hospitals, clinics, businesses, prisons, government and private practice
• Activities include psychological counseling, educational testing, research, teaching, and consulting
• Psychiatrists are medical doctors who specialize in mental, behavioral, and personality disorders
• Psychiatrists can prescribe medication and often collaborate with other health professionals
• Social workers help individuals, families, and groups deal with personal and practical problems within a community
• Social workers are committed to human rights, social justice, and improving human well-being

The Scientific Method

• The scientific method involves gathering data and processing information to advance scientific knowledge
• Hypotheses are tested through objective and tangible empirical observations
• Basic steps of the scientific method used in psychology:
  • Identifying a research question
  • Making a prediction by formulating a null and alternative hypothesis
  • Designing a method to test the hypothesis
  • Conducting an experiment to collect data
  • Processing data through analysis and evaluation
  • Drawing conclusions and reporting the findings

Independent and Dependent Variables

• Experimental research uses independent and dependent variables
• The independent variable (IV) is changed to measure the effect on the dependent variable (DV)
• The dependent variable is what is tested/measured and it depends on the independent variable
• Experiments investigate the effect of an independent variable on a dependent variable (cause and effect relationship)
• In the coffee and memory example, coffee/water is the independent variable and memory is the dependent variable
• The independent variable can have different levels or conditions
• Drinking coffee is the experimental condition, and drinking water is the control condition which allows the research to compare participants in each condition

Operationalisation of Variables

• Researchers must establish how independent and dependent variables will be measured
• Operationalisation defines and measures exactly how a specific variable will be used in an experiment
• In the coffee and memory example, the amount of coffee/water (e.g. 500ml) and when it is drunk (e.g. 1 hour before a test) would be specified
• Dependent variable operationalisation includes use of a memory recall test of 20 items
• Operationalisation allows other researchers to replicate and compare research, increasing reliability

Extraneous and Confounding Variables

• Extraneous variables (EV) are variables other than the independent variable that may affect the dependent variable if not controlled
• Unwanted EVs must be minimised to ensure only the independent variable affects the dependent variable
• EVs do not vary with the independent variable
• For example, the age of a participant in an EV that can be controlled by the researcher
• A confounding variable has not been properly controlled and has an effect on the dependent variable

Confounding Variables

• Confounding variables may affect the dependent variable and cause the source of change to the dependent variable is unknown
• Confounding variables vary with the independent variable
• For example, personality is a confounding variable that is difficult to control

Hypothesis

• A hypothesis is a clear, precise, testable statement predicting the relationship between two variables
• It predicts what changes will occur on the dependent variable when the independent variable is manipulated
• It's an experimental hypothesis
• 2 Types of hypotheses:
  • Directional (one-tailed): states the direction of the difference or relationship
  • Non-directional (two-tailed): does not state the direction
• In psychology, an experimental hypothesis can be the alternative hypothesis
• The null hypothesis assumes there is no relationship between the variables being investigated
• There is no change in the dependent variable due to the manipulation of the independent variable
• When one of these hypotheses is accepted, then the other will be rejected