The Science of Psychology

Chapter 1The Science of PsychologyWhat can psychology do?Psychology can help us understandHow culture may influence personalityWhy you find some people attractive but not othersWhat IQ test scores really meanHow prejudice formsHow different are men and women?Why buying lottery tickets can be so addictive

Why Study Psychology???Help understand why people (and animals) behave the way they doHow brain and body are connectedHow do improve learning abilities and memoryHow to deal with life stressesVery important: Understanding of research methods in psychology because research can be flawedCritical thinkingEvaluation of research, advertisements, and politicians

What is psychology?Psychology the scientific study of behavior and mental processesBehavior all outward or overt actions and reactions (i.e., talking, facial expressions, movement)Mental processes all the internal, covert activity of our minds (i.e., thinking, feeling, remembering)Psychology is scientificIn observation of behavior must avoid bias or the possibility of seeing only what you expect to seeBias personal judgments based on beliefs rather than factsBias leads to faulty observationsThus, psychologists use the scientific method4 Goals of Psychology - Description1st Goal - description Provides observations Observing a behavior and noting everything about itWhat is happening, where it happens, who it happens to, and under what circumstances Example: Why are so many computer scientists male?Description: through observations you note that many non-techies hold stereotypical views of the life and environment of computer scientistsSurrounded by computer games, junk food, science-fiction gadgets, love star trek = masculine environment These observations seem to add up to a more masculine view of computer scientists Descriptions lead to the next goal: Why do females seem to avoid this environment4 Goals of Psychology - Explanation2nd Goal - explanationBased on observations, the next step is attempting to explain those observationsExample: finding an explanation for the lower proportion of women in computer science possible explanation: women may feel they do not belong in such a stereotypically masculine environmentFinding explanations is an important step in the process of forming theories of behaviorTheory a general explanation of a set of observations or facts

4 Goals of Psychology - Prediction3rd Goal: predictionPrediction determining what will happen in the futureExample: if we want more women to go into computer science, we must do something to either:Change the environment Change the perception of the environment typically associated with this field4 Goals of Psychology - Control4th Goal: control modification of some behaviorPurpose is to change an undesirable behavior to a desirable oneExample: change behaviors to promote more equality in career choices Changing the image of computer science as a field may help increase the number of women choosing to go into this field4 Goals of PsychologyNot all psychological investigations try to meet all 4 of the goalsSome may focus on description and predictionEx. Personality theorist who wants to know what people are like (description) and what they might do in certain situations (prediction)Some may focus on description and explanationEx. Experimental psychologists who designs research to find explanations for observed (described) behaviorTherapists may be more interested in controlling or influencing behavior and mental processesBut, the other three goals would be important in achieving this objectiveHistory of PsychologyField has only officially existed for about 130 yearsBefore psychology, behavior was studied by philosophers, medical doctors, and physiologists Philosophers tried to understand/explain the human mind and its connection to the physical bodyAristotle (384-322 B.C.) soul and body were both part of the same underlying structurePlato (427-347 B.C.) soul exists separate from the body (dualism)Rene Descartes (17th-century French philosopher/mathematician) dualism, suggested that the pineal gland (small organ at the base of the brain) was the link between the soul and body

History of PsychologyMedical doctors and physiologists studied the physical connection between the body and the brainGustav Fechner (physician/physicist) credited with some of the first scientific experiments that formed a basis for psychological studies of perceptionHermann von Helmholtz (physician) performed groundbreaking experiments in visual and auditory perception

History: Wundt and IntrospectionWilhelm Wundt (physiologist) father of psychology1st attempt to bring objectivity and measurement to psychology1st psychology laboratory in Leipzig, Germany 1879Believed the mind was made up of thoughts, experiences, emotions, etc.Objective introspection the process of objectively examining and measuring ones own thoughts and mental activitiesEx. A rock is placed in your hand, you note everything that you feel as a result of having a rock in your hand (i.e., sensations stimulated by the rock, how heavy it is, its texture etc.)

History: Titchener & StructuralismEdward Titchener (1867-1927) Cornell University - Wundts studentExpanded Wundts ideas into a new viewpoint called structuralism (because the focus was on the structure of the mind)Believed every experience could be broken down into its individual emotions and sensations Believed objective introspection could be used on thoughts in addition to physical sensationsEx. What is blue? there are blue things, like the sky. Blue is cool and restful, blue is calm etc.There is no actual object, just introspection regarding your thoughts about blueStructuralism was an early dominant viewpoint in psychology, but died out in the early 1900sInteresting tidbit: Titchener graduated the first female Ph.D in psychology, Margaret F. Washburn, in 1894

Exam bonus question: Titchener graduated the first female Ph.D in psychology in 189413History: James & FunctionalismWilliam James (1842-1910) Harvard UniversityWrote Principles of Psychology, a comprehensive book on psychology (still in print today)Opposed structuralism More interested in the importance of consciousness to everyday life (rather than just its analysis like Wundt and Titchener)However, believed the study of consciousness itself was not yet possible (because consciousness is an ever-changing stream)Focused on functionalism - how the mind allows people to function in the real worldHow people work, play, and adapt to their surroundingsInteresting tidbit: Harvard was the 1st school in America to offer classes in psychology

History: James & Functionalism (cont.)Functionalism was largely influenced by Charles Darwins ideas about natural selection (i.e., physical traits that help an animal adapt and survive are passed on to its offspring)Behavioral traits could also be adaptive Animals and people whose behavior helped them survive would pass those traits to their offspring, via teaching or a mechanism of heredity Example: Behavior like avoiding eye-contact in a crowded elevator can be seen as a way of protecting ones personal spaceMay be rooted in the primitive need to protect ones home from intruders or as a way of avoiding what might seem like a challenge to another personFunctionalism is no longer a major viewpoint in psychology but its elements can be found in the modern fields of educational psychology and industrial/organizational psychologyEarly Sexism in PsychologyMary Whiton Calkins one of James early studentsCompleted every credit and requirement for a Ph.D. under James at HarvardDenied a Ph.D. because she was a womanEventually established a psychological laboratory at Wellesly College for womenConducted some of the earliest research in the area of human memory and the psychology of the self1905 became the first female president of the American Psychological AssociationUnlike Washburn, Calkins never earned a Ph.D. despite a successful career as a professor and researcher

Early Minority Influences in PsychologyFrancis Cecil Sumner in 1920 first African American to earn a Ph.D. in psychology at Clark University Known as the father of African American psychology

Kenneth & Mamie Clark worked to show the negative effects of school segregation on African American children

Jorge Sanchez early Hispanic psychologist who conducted research on intelligence testing, focusing on the cultural biases in the tests.

History: Gestalt Psychology - The whole is greater than the sum of its partsMax Wertheimer (German) objected to structuralismPsychological events such as perceiving and sensing could not be broken down into smaller elements and still be properly understoodEx. If you take an ipod apart, you no longer have an ipod, just a bunch of unconnected bits and pieces Gestalt Psychology Focus on studying whole patterns rather than small pieces of themPeople naturally seek out patterns (wholes) in the sensory information available to themToday Gestalt ideas are part of cognitive psychology as well as other areas

History: Sigmund Freud & Theory of PsychoanalysisDuring the rise of structuralism, functionalism, and Gestalt psychologySigmund Freud neurologist in Austria focusing on disorders of the central nervous systemAttempting to understand nervous disorders with no physical causeSuggested existence of an unconscious (unaware) mind into which we push, or repress, all of our threatening urges and desiresBelieved repressed urges, trying to surface, created nervous disordersBelieved phobias (irrational fears) were a symptom of an underlying, repressed conflict

History: Sigmund Freud & Theory of Psychoanalysis cont.Freud stressed importance of early childhood experiencesBelieved personality was formed in the first 6 years of lifeIf an individual had significant problems, the problems must have begun in the early years of lifePsychoanalysis the theory and therapy based on Freuds ideasBasis of much modern psychotherapy (a process in which a trained psychological professional helps a person gain insight into and change his or her behavior)

History: Pavlov & ConditioningIvan Pavlov Russian physiologistPavlovs Conditioning - Showed that a reflex (an involuntary reaction) could be caused to occur in response to a formerly unrelated stimulusDog study:

History: Behaviorism & WatsonJohn B. Watson Challenged structuralism, functionalism, and psychoanalysisBehaviorism science of behavior focuses only on observable behaviorCompletely ignored consciousness and focused only on observable behavior (something that could be directly seen and measured)Believed all behavior is learnedBelieved that phobias are learned through the process of conditioningTook Pavlovs classical conditioning and applied it to humansWatson & The Little Albert StudyWatson, in opposition to Freud, wanted to show that phobias were learned through the process of conditioningPrior to conditioning, Albert showed no fear when presented with a white ratNext, every time Albert was presented with the rat Watson made a loud, frightening noise behind himAfter multiple parings of the rat and the noise Albert showed fear when presented with the rathttp://www.youtube.com/watch?v=Xt0ucxOrPQE

Modern PerspectivesPsychodynamic PerspectiveModern version of Freuds psychoanalysisLess focused on sex and sexual motivations than Freuds psychoanalysis More focused on the development of sense of self, social and interpersonal relationships, and the discovery of other motivations behind behaviorBehavioral PerspectiveAfter Watson, B.F. Skinner became the new leader of the fieldSkinner theory of operant conditioning behavioral responses that are followed by pleasurable consequences are strengthened, or reinforced; behaviors followed by negative consequences will diminish over time (called punishment) We will discuss this more in chapter 5

Modern PerspectivesHumanistic PerspectiveKnown as the third force in psychologyFounded by Abraham Maslow and Carl Rogers in early 1900sContrast to psychoanalysis and behaviorismFocused on peoples ability to direct their own livesPeople have free will the freedom to choose their own destinyPeople strive for self-actualization the achievement of ones full potential

Modern PerspectivesCognitive PerspectiveBecame a major force in the 1960sFocuses on how people think, remember, store, and use informationIncludes memory, intelligence, perception, thought processes, problem solving, language, and learningCompares the brain to a computerCognitive neuroscienceNew field studying the physical workings of the brain and nervous system when engaged in memory, thinking, and other processesUse MRI, fMRI, PET to study the structure and activity of the living brainModern PerspectivesSociocultural PerspectiveCombines two areas of psychology:Social psychology the study of groups, social roles, and rules of social actions and relationshipsCultural psychology the study of cultural norms, values, and expectationsFocus on the effect that people have on one another, either individually or in a larger groupThe way people behave (or even think) is influenced by who is around whether alone, with friends, in a crowd, or part of a group As well as by social norms, fads, class differences, and ethnic identity of the particular culture in which they liveModern PerspectivesBiopsychological PerspectiveThe study of the biological bases of behavior and mental processesHuman and animal behavior is seen as a direct result of events in the bodyCauses of behavior and mental events: hormones, heredity, brain chemicals, tumors, and diseases Study topics such as sleep, emotions, aggression, sexual behavior, learning, memory, mental disordersDisorders may have multiple causes but focus if placed on biological factorsEx. Genetic and hormonal causes of schizophrenia

Modern Perspectives Evolutionary PerspectiveFocus on the biological basis for universal mental characteristics that all humans shareSeeks to explain general mental strategies and traitsEx. Why people lie, how attractiveness influences mate selection, why fear of snakes is so commonMind is seen as a set of information-processing machines, designed by the process of natural selection, allowing humans to solve the problems they faced in the early days of evolutionEx. Behavior of not eating things with a bitter taste most likely evolved as early humans came into contact with bitter plants that were most likely poisonous. Humans who didnt eat the plant survived to pass on their genesEx. Difference between men and women in response to sexual vs. emotional infidelity

Psychological Professionals and Areas of SpecializationPsychology is a large field with many areas of specialization requiring different trainingRefer to Figure 1.2 in the textbookLargest subfield of psychology is clinical psychologyLargest percentage (35%) of psychologists work at 4-year universities

PsychologistsPsychiatristsNo medical trainingMedical trainingDoctorate degree (Ph.D.)Medical Doctor (M.D.)Many areas of specializationSpecialize in diagnosis/treatment of psychological disordersNot able to prescribe medicationAble to prescribe medicationPsychology: Scientific Methodology Scientific method a system for reducing bias and error in the measurement of dataSystem aids psychologists in accomplishing the 4 goals (remember?...description, explanation, prediction, and control)5 StepsPerceiving the questionForming a hypothesisTesting the hypothesisDrawing conclusionsReporting results

Scientific MethodStep 1 - Perceiving the QuestionNotice something interesting and want and explanationGoal of description Ex. Notice that your kids seem more aggressive with each other after watching a violent cartoon on Saturday mornings Step 2 Forming a HypothesisHypothesis (educated guess) tentative explanation for your observationsStatement that can be tested in some way Hypothesis children who watch violent cartoons become more aggressive Goal of description and explanation

Scientific MethodStep 3 Testing the Hypothesis Must avoid confirmation bias (the tendency to only notice things that agree with ones view of the world)Scientific method seeks to avoid bias by forcing researchers to seek out information that may contradict their biases Thats why psychologists do research over and over, to gain more support for their hypothesis Testing method selected depends on what kind of answer you think you may getMore detailed observationsSurvey asking questions to a large number of people Experiment in which you deliberately change one thing to see if it causes changes in the behavior you are studying What do you think is the best way to test our kids & cartoons example?

Scientific MethodExperiment: 2 groups of kids

Group 1Group 2

Watch Violent CartoonWatch Nonviolent CartoonMeasure kids aggressive behaviorMeasure kids aggressive behavior

Scientific MethodStep 4 Drawing Conclusions Results of hypothesis testing can either support or not support your hypothesis Support: experiment worked! Measurements supported initial observationsEx. If kids who watched the violent cartoon were more aggressive than kids who watched the nonviolent cartoonNot Supported: back to square 1! Think of other possible explanations for what was observedEx. No difference in aggression between group 1 and group 2 maybe kids are just more aggressive on Saturday mornings, maybe its the breakfast they eat on Saturdays? Goal of prediction if hypothesis was supported, then you can make educated guesses about future, similar scenarios

Scientific MethodStep 5 Report Your ResultsOnce you have come to a conclusion, you want to let other researchers know what you found even if your hypothesis was not supportedWrite up exactly what you did, why you did it, how you did it, and what was foundOthers may replicate (do exactly the same thing you did) and add support to your findings Peer reviewed journals, posters and speaking at conferences, etc.Even if your experiment didnt workMaybe poor study designMaybe other outside factors effected resultsShow other researchers what doesnt work so the same unsuccessful experiments arent repeatedAdd more to knowledge baseGoal of control findings may help to make predictions and ultimately modify or control behavior

Descriptive Methods: Naturalistic ObservationAGAIN: method depends on the kind of question to be answeredNaturalistic ObservationObserving people/animals in their normal environmentAnimals natural habitat, where they eat, play, sleep, and matePeople workplaces, homes, social settings, playgroundsAdvantage: realistic picture of how behavior occurs in its natural settingObserver should have a list of well-defined, specific behaviors Avoid observer effect (when animals or people dont behave normally because they know theyre being watched)Usually want to be hidden

Descriptive Methods: Naturalistic Observation (cont.)Disadvantages Observer bias observer only recognizes actions that support their opinion and ignores actions that contradict itHow to avoid: use blind observers (people who dont know what the research question is, so they cant have preconceptions)How to avoid: use multiple observers so observations can be compared Lack of controlCannot ensure that each time behavior is observed the setting will be exactly the sameObservations that are made at one time in one setting may not hold true for another time, even in a similar setting Descriptive Methods: Laboratory ObservationSometimes its not practical to observe people/animals in their natural settingAdvantage: allows researcher control over the settingCan ensure that environment is the same for each observationDisadvantage: artificial situationPeople/animals tend to behave differently in the laboratory than they would in the real world

Descriptive Methods: Case StudiesIn depth study of a single individualTry to learn everything possible about that individualAdvantage: tremendous amount of detail Advantage: may be the only way to get certain kinds of informationEx. Traumatic brain injuryDisadvantage: cant generalize to other similar casesCant assume that if another person had the same kind of experiences he/she would turn out the same as the individual in the case studyDisadvantage: vulnerable to bias on the part of the researcher

Descriptive Methods: SurveysGood way to gain information about private behaviors (ex. Sexual behavior)Ask a series of questions about the topic being studiedCan be conducted in person (interviews), over the phone, internet, or with a questionnaireAdvantage: can ask lots of questions and survey a large number of peopleDisadvantage: must be careful about the group of people surveyedPopulation group of interest in the studyEx. College freshman Representative sample sample that accurately represents the target populationEx. Cant survey every single college freshman, but can randomly survey groups of freshman from several different collegesSelection is random (ex. If you only surveyed freshman from Ivy League colleges, not all types of freshman will be represented in the sample)Disadvantage: peoples answers arent always accurate Misremembering, distorting the truth, outright lying

Finding Relationships: CorrelationCorrelation a measure of the relationship between two or more variablesVariable anything that can change or vary (ex. Test scores, room temperature, gender, etc.)Example: is cigarette smoking connected to life expectancy (the # of years a person can be expected to live)?Could look at medical records: see # of cigarettes smoked per day and the age people were when they diedInformation related to these 2 variables are entered into an equation which produces a correlation coefficientCorrelation coefficient # that represents 2 things: the direction and strength of the relationship between variables

Finding Relationships: Correlation When 2 variables are related, it means that if you know the value of one, you can predict the value of the otherEx. Smoking and life expectancy are related, knowing how many cigarettes a person smokes a day would allow you to predict how long they will liveDirection - as # of cigarettes goes up, does life expectancy go up or down?Correlation coefficient (represented by r) will either be a positive or a negative #Positive variables increase and decrease in the same direction, if one increases, so does the other, if one decreases, so does the otherNegative inverse relationship, if one increases the other decreases Ex. If as # of cigarettes increases, life expectancy decreases, then the relationship is negative or inverse Finding Relationships: Correlation Strength of the relationship is determined by the actual value of the correlation coefficientCan range between +1.00 and -1.00The stronger the relationship the closer the correlation coefficient will be to either +1.00 or -1.00 (weaker relationships will be close to 0)Ex. 0.89 is a strong positive correlationEx. -0.89 is a strong negative correlationExample: if the correlation coefficient between smoking and life expectancy was r = -0.87, this would represent a strong negative correlation, as one variable increases, the other decreasesFinding Relationships: Correlation

Finding Relationships: CorrelationIMPORTANT: just because there is a correlation between 2 variables DOES NOT mean that one causes the other!Causation cannot be determined from correlationThere could be a 3rd variable, not measured in the study, that causes the relationshipEx. Relationship between smoking and life expectancy could be due to the tendency of people who smoke to not take very good care of their health in generalCorrelation can provide the starting point for examining causal relationships with an experimentFinding Relationships: ExperimentOnly method that allows for determining causeDeliberately manipulate (change) the variable you think is causing some behavior while keeping all other variables that may effect the relationship constant and unchangingThis way, if the behavior changes (i.e. an effect), it must be due to the changes in the manipulated variableExample: effects of watching violent cartoons on kids aggressive behaviorFirst, must select kids to use in the experimentDetermine age range of interest (ex. 3-4 years old)Randomly select a certain # of kids in that age range (from daycares or pediatricians offices maybe)Finding Relationships: Experimentindependent variable - the variable to be manipulated the one thought to be causing the change in behaviorIndependent because it is independent of anything the participants doEx. Cartoon violence dependent variable - the variable to be measured to see if there are any changes this is the effect of the manipulation on behaviorDependent because it depends on the manipulation of the independent variableEx. Kids aggressive behaviorMust define both the manipulated variable and the measured variable Operational definition specifically names the operations (steps or procedures) that must be used to control or measure the variables in the experimentEx. Aggressive behavior checklist: hitting, pushing, etc.Finding Relationships: ExperimentConfounding variables variables that interfere with each other and may have an effect on the relationship being measuredMust be controlledEx. Some kids may just be more aggressive in general, or maybe kids tend to be more aggressive at the particular time of day they were observedBest way to avoid confounding variables is to use 2 groupsOne group watches a violent cartoonOne group watches a nonviolent cartoon for the same amount of time

Finding Relationships: ExperimentExperimental Group group that receives the manipulationControl Group group that receives no treatment or a treatment that should have no effectIf both groups were equally aggressive then the violent cartoon did not effect behavior

Experimental GroupControl Group

Watch Violent CartoonWatch Nonviolent CartoonMeasure kids aggressive behaviorMeasure kids aggressive behavior

Finding Relationships: ExperimentRandom assignment randomly assigning participants to either the experimental or control conditionMeans that each participant has an equal chance of being assigned to each condition (experimental or control)Best way to ensure control over interfering or extraneous variablesFinding Relationships: ExperimentExperimental HazardsPlacebo effect when participants expectations or beliefs about a study effect their behavior in the experiment more likely when studying people rather than animalsEx. Studying the effects of a new drug, participants expect behavior to improve because they believe thats what the drug is supposed to doAvoid by using a control group who receives a placebo (which has no effect)Finding Relationships: ExperimentExperimental HazardsExperimenter effect similar to bias while measuring the dependent variable, the researcher gives participants clues about how they are supposed to respondCan be through body language, tone of voice, eye contactEx. Alzheimers patient is taking a 2nd memory test after receiving an experimental drug, experimenter pays a excessive amount of attention to each answer the participant givesParticipant may think he/she should have improved a lot and tries really hard on the test, thus improvement is due to the patients increased effort, not to the drug

Finding Relationships: ExperimentSingle-blind study participants are unaware of whether they are in the experimental group or the control groupUnaware if they are receiving the manipulation or notEx. Testing a new drug: experimental group gets the drug, control group gets a sugar pill, but are unaware which they were givenReduces the placebo effect because results of both groups are compared, even if both groups improve due to placebo effect, the experimental group should improve more if the drug is effective

Finding Relationships: ExperimentDouble-blind study both participants and experimenters measuring behavior are unaware of which condition (experimental or control) participants are inHelps reduce experimenter bias experimenter cannot give clues if they are unaware of what should be happeningEvery element is coded in some way so that only after all the measurements have been taken can it be determined who was in which groupFinding Relationships: Quasi-ExperimentalAlternative research design used when participants cannot be randomly assigned to experimental or control groupsThis is why its only quasi experimental, lack of random assignment to groupsThese studies are not considered true experimentsExample: how does age influence behavior?Age independent variableCant just randomly assign participants to be a certain ageExample: behavior differences between men and womenGender independent variableCant randomly assign participants to be either men or women Ethics of Psychological ResearchRemember the Little Albert experiment?Seems pretty cruel right?People who volunteer to participate in studies should be able to expect that no physical or psychological harm will come to themInstitutional Review Boards (IRB) groups of psychologists or other professionals who look over each proposed study and judge it according to its safety and consideration for the research participantsAnalyze all aspects of each proposed study (written materials, participant consent forms, equipment used in the study, etc) Guidelines for doing research with people1) Rights and well-being of participants must be weighed against the studys value to sciencePeople come first, research comes second2) Participants must be allowed to make an informed decision about participationInformed consent - Before researchers can do ANYTHING, participants must be informed in terms that they understand what will happen during their participation If participants are minors, parents must be informed3) Deception must be justifiedSometimes it is necessary to deceive participantsDebriefing - After the study, participants must be informed of the deception used and why it was important

Guidelines for doing research with people4) Participants may withdraw from the study at any time for any reasonEx. If participants get bored or uncomfortable 5) Participants must be protected from risks or told explicitly about risksEx. If using electrical equipment, care must be taken to ensure no participant is shocked 6) Investigators must debrief participants, telling the true nature of the study and expectations of resultsEspecially important in studies involving deception

Guidelines for doing research with people7) Data must remain confidential Importance of confidentialityReport only group results so that no one can be identified 8) If for any reason a study results in undesirable consequences for the participant, the researcher is responsible for detecting and removing, or correcting, these consequencesSometimes people react to manipulations in unexpected waysResearchers is responsible for helping individuals overcome negative impacts of the study Research on AnimalsUsing animals aids in answering research questions that would be impossible using peopleEasier to control, engage in simpler behavior so easier to see effects of manipulationsAnimal research has played key roles in the development of vaccines for deadly diseases, insulin treatments for diabetics, transplant surgeries, etcMajor guideline must avoid exposing research animals to any unnecessary pain or sufferingEx. If study involves surgery, must use anesthesiaEx. If the animal must be killed to study postmortem effects, death must be accomplished in the most humane way possibleApplying Psychology to Everyday Life: Thinking Critically About Critical ThinkingCritical thinking making reasoned judgmentsReasoned judgments should be logical and well thought-outIncludes the ability to ask and seek answers for critical questionsEx. Do you have any good evidence for your assertions, or are you just giving your opinion?Example: I should think more critically about products on infomercials Then maybe I wouldnt have wasted $ on a Pasta Boat but I still think the Snuggie was a good decision

4 Basic Criteria for Critical Thinking1) There are very few truths that do not need to be subjected to testingQuestions that can be investigated empirically should be examined using established scientific methodsEx. Many people still believe in Astrology, but scientific investigations have shown time after time that astrology has no basis in truth or scientific fact2) All evidence is not equal in qualityEvidence should be evaluated before deciding it is good support for some ideaPoorly done experiments, incorrect assumptions based on correlations, studies that could not be replicated, studies using no control group, no examination of placebo or experimenter effects, deliberate manipulations of findings Ex. How much evidence is there really to support alien visitationEx. Faked data led to thousands of parents refusing to allow their children to be vaccinated because they believed vaccinations caused Autism which has in turn led to the resurfacing of diseases that were nearly eliminated

4 Basic Criteria for Critical Thinking3) Just because someone is considered to be an authority or to have a lot of expertise does not make everything that person claims automatically trueShould never just take an experts word for it, always ask to see the evidenceIf there are two explanations for some phenomenon the simplest one is more often the best one (known as the rule of parsimony)Example: Crop circles2 explanations: either made by aliens in space ships (as claimed by many experts) or made by humans as a hoaxObviously, the hoax explanation is the simplest And it turned out to be correct for the crop circles that appeared in England in the 1970s and 1980s (the pranksters, Doug Bower and Dave Chorley, came clean about making the circles in 1991)

4 Basic Criteria for Critical Thinking4) Critical thinking requires an open mindGood to be skeptical but shouldnt close your mind to things that are truly possibleBalance between skepticism and willingness to consider other possibilities even possibilities that contradict previous judgments or beliefsExample: there is not yet any convincing evidence that there was once life on MarsBut that doesnt mean scientists dismiss the idea, just no convincing evidence yet