class: center, middle, inverse, title-slide # Scientific methods in psychology ## ⚔<br/>with xaringan ### Goran Kardum ### Department of Psychology ### 2021-10-06 --- ``` ## Loading required namespace: bibtex ``` # Scientific Methods in Psychology The scientific method was first proposed by Sir Francis Bacon (1561-1626) to provide logical, rational problem solving across many scientific fields. -- The basic steps of the scientific method: - make an observation that describes a research problem, - create a hypothesis, - test the hypothesis, - draw conclusions and refine the hypothesis. -- The aim of the scientific method are - verifiability, - predictability, - falsifiability, - fairness. -- The application of the scientific theory to psychology took the discipline from a form of philosophy to a form of science. Critical thinking is a key component of the scientific method. Without it, you cannot use logic to come to conclusions. # Social sciences vs. natural sciences Psychology as a science concerned with the social behavior of individuals and groups that are often considered more subjective due to the subject of study. -- Scientific method: A method of discovering knowledge about the natural world based on making falsifiable predictions (hypotheses), testing them empirically, and developing peer-reviewed theories that best explain the known data. -- Natural science: Sciences concerned with predicting and describing natural phenomena (e.g., biology, physics, or chemistry), using systematic data collection and performing controlled experiments. --- # Steps in scientific study? - Hypothesis -- - Method -- - Results -- - Interpretation --- # Hypothesis  --- # Evaluating scientific theory [1] "" - Falsifiable (theory state at position as clear, precise terms that we can see what evidence would count against it) -- - Parsimony --- # General Research Principles (some of them) Operational Definitions [1] "" - A definition that specifies the operations (or procedures) used to produce or measure something, ordinarily a way to give it a numerical value -- - That definition must fit clear sentences that include procedure to measure subject of measurement -- Population samples - convenience sample -- - representative sample -- - random sample ---  --- # Observational research design - Naturalistic observations (is careful examination of what happens under more or less natural conditions) -- - Case histories (a thorough description of someone, including abilities and disabilities, medical condition, life history, unusual experiences, and whatever else seems relevant) -- - Surveys (a study of the prevalence of certain beliefs, attitudes, or behaviors based on people's responses to questions) - Sampling -- - The seriousness of those being interviewed -- - the wording of the qestions -- - surveyor biases -- - Correlation studies - the correlation coefficient -- - illusory correlations -- - Correlation is not Causation --- # Experiments A study in which the investigator manipulates at least one variable while measuring at least one other variable. -- - Different type of variables - independent variable -- - dependent variable -- - Different type of group -- - Control group -- - Experimental group -- - Experimenter bias and blind studies -- - blind observer -- - single blind study -- - double blind study -- - different experimental design (e. g. before-after study) --- # Evaluating the Results - Descriptive statistics -- - Inferential statistics -- - Replicability issues --- # Ok, that's it... for the first part -- # Now we have some kind of exam... for 5-10 minutes -- # Let's go out! 10 minutes according to epidemiological suggestions --- # Biological Psychology Almost any statement about the nervous system has exceptions! --- # Neurons and Behavior Neurons consists of three parts: - a cell body -- - dendrites -- - axon -- and... -- - glia cells - support the neurons in synchronizing activity among neighboring neurons, removing waste products --- ## Neurons vary enormously in size and shape  --- ## Estimated distribution of neurons in aduld human CNS  --- ## The Action Potential The Action potential is the main function of the neuron to convey information over long distance e.g. from skin to the primary sensor area in the brain... -- Phenomenon 1: 'All or none' law: all axons throughout the nervous system produce action potentials of equal strenght -- Phenomenon 2: An excitation that travels along an axon at a constant strength... no matter how far it travels --  --- ## Signaling Two important concepts: resting potential and threshold -- Resting potential: -70mV -- Threshold: -55mV.... starting influx of sodium ion... ---  ---  --- ## Neurons communicate chemically  --- ## Neural communication takes only 1 - 2 seconds  --- ## Important neurotransmitters  --- # Drugs and Their Effects Psychoactive drugs affect synapses trough mechanisms: -- - agonist: drug that increase activity at synapses -- - antagonist: drug that decrease activity at synapses -- - produce altered states of consciousness -- - receptors ... reuptake phenomenon --- ## Stimulants Drugs that increase energy, alertness and activity -- - amphetamine, methaphetamine and cocaine: block the protein that the presynaptic neuron uses to reabsorb dopamine or serotonin after release them -- - tobacoo, nicotine: affect acetylcholine -- - increases arousal, higher hart rate, higher blood pressure --- ## Hallucinogens Drugs that induce sensory distortions that are called hallucinogens or psychedelic. -- - LSD (lysergic acid diethylamide): attaches mainly one kind of serotonin -- - MDMA (methylededioxymethamphetamine): increase body temperature, change reality --- ## Depressants The drugs that decrease arousal, such as alcohol and anxiolytics. -- - Alcohol -- - Anxiolytic drugs or tranquilizers (benzodiazepines, diazepam, alprazolam like Xanax) -- - GHB (gamma hudroxybutyrate) --- ## Drugs and their effects  ---  ---  --- # Brain and Behavior Monism - the idea that mental activiry and brain activity are inseparable. --  --- ## The Cerebral Cortex The vertebrate brain has three major divisions: hindbrain, midbrain and forebrain. --  --- ## A view of the forebrain The important part and functions of temporal lobe (amigdala) --  --- ## The parietal lobe of the cortex  --- ## The two hemispheres  --- ## The Autonomic Nervous System  ---  --- ## Measuring brain activity - EEG -- - fMRI - functional magnetic resonance -- - PET - positron emission tomography --- ## PET scan  --- ## fMRI  --- # Genetics and Evolutionary Psychology Humans has tens of thousands of genes that control development. -- - Genetics - dominant and recessive -- - Behavioral genetics -- - Epigenetics ---  ---  --- ## Estimated heritability - twin studies / brothers and sisters -- - studies of adopted children --- - Population in statistics describe as totality or all subjects / entities which reference is to be made -- - Population reference to all subjects / entities with same one or several atributes -- - A population statistics has no error! -- - Sample is finite number of subjects / entities from population -- - Sample is subset of population and statistics in 99% of research deal with them. Not with population! -- - When we deal with sample that means all statistics have error. We estimate population parameters. -- - Sampling is main step in the research design. We could not change that in next steps.... statistical analysis could! --- # Uncertainty and error - Errors and uncertainty are exists in any research -- - Statistical procedure estimate the amount of errors and/or uncertainty -- - Statistical knowledge expressed as probability -- - Probability is main term / concept of statistical explanation --- # Degrees Degrees of research associate with statistical complexity; 1. Descriptive level -- 2. Interpretative level -- 3. Prediction level --- # Statistical inference - Explaratory data analysis or descriptive statistics -- - Statistical inference or inferential statistics --- # Definitions Two main parts of statistics [1] "" - Descriptive statistics are procedures used to summarize and describe the important characteristics of a set of measurements. -- - Inferential statistics are procedures used to make inferences (that is, draw conclusions, make predictions, make decisions) about a population from information contained in a sample drawn from this population. --- # Close connection with research methods - estimation and hypothesis testing -- - research design -- - correlation research vs. experiments -- - quantitative analysis -- - but! not only... qualitative analysis needs some calculation and software --- # Variables Simple point out about some kind of variables:[@dancey_2020] - Continuous variables can take on absolutely any value within a given range. -- - Discrete variables can only take on certain discrete values in a range. -- - Categorical variables are those in which we simply allocate people to categories. --- # References ``` ## You haven't cited any references in this bibliography yet. ``` NULL --- class: center, middle # Thanks! 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