Presentation on theme: "Thinking Critically with Psychological Science Chapter 1"— Presentation transcript:
1Thinking Critically with Psychological Science Chapter 1 Psychology 7e in Modules
2Scientific MethodPsychologists, like all scientists, use the scientific method to construct theories that organize, summarize and simplify observations.Making observationsDefining a problemProposing a hypothesisGathering evidence/ testing hypothesisPublishing resultsTheory buildingOBJECTIVE 4| Describe how psychological theories guide scientific research.Psychology 7e in Modules
3Hypothesis Expresses a relationship between two variables. A variable is anything that can vary among participants in a study.Participating in class leads to better grades than not participating.
4TheoryA Theory is an explanation that integrates principles and organizes and predicts behavior or events.For example: low self-esteem contributes to depression.If we were to observe that depressed people talk about their past, present, and future in a gloomy manner, we may theorize that low-self-esteem contributes to depression.Psychology 7e in Modules
5Research Observations Research would require us to administer tests of self-esteem and depression. Individuals who score low on a self-esteem test and high on a depression test would confirm our hypothesis.
6Publishing results –write and publish article Making observations computer game designers have varying levels of stressDefining a problem In what ways are high stress and low stress game designers different? High control vs. Low control?Proposing a hypothesis Game designers who have more control over difficult tasks will report less stressGathering evidence/ testing hypothesis (Randomly assign subjects into two groups:Forced pace (low control) = high stressSelf pace (high control) = low stressPublishing results –write and publish articleTheory building use the results to create theory that explains having control over a task reduces stress
7Below is a comparison of different research methods.
8Experimentation Exploring Cause and Effect Test hypothesis Type 1 of Research methodExploring Cause and EffectTest hypothesisHas control and experimental groupsLaboratory experiments are good at controlling variables.Eating too many bananas causesConstipationOBJECTIVE 12| Explain how experiments help researchers isolate cause and effect.Psychology 7e in Modules
9To Perform an Experiments Directly vary a condition you think might affect behaviorCreate 2 or more groups of subjectsShould be alike in all ways except the condition varyingRecord whether varying condition have a effect on behavior
101. Experimental subjects/objects. A. Experimental group. B 1. Experimental subjects/objects A. Experimental group B. Control groupVariable- any condition that can change or affect the outcome of experimentIndependent variableDependent variableExtraneous Variable
11Independent Variable Factor manipulated by the experimenter. Focus of the study.The cause of the behaviorFor example, when examining the effects of breast feeding upon intelligence, breast feeding is the independent variable.OBJECTIVE 14| Explain the difference between an independent variable and a dependent variable.If there is a drug in an experiment, the drug is almost always the independent variable.Psychology 7e in Modules
12Dependent Variable Whatever is being measured in the experiment. It is dependent on the independent variable.The dependent variable would be the effect of the drug.For example, in our study on the effect of breast feeding upon intelligence, intelligence is the dependent variable.
13Beware of Confounding/Extraneous Variables The object of an experiment is to prove that A causes B.A confounding variable is anything that could cause change in B, that is not A.If I wanted to prove that smoking causes heart issues, what are some confounding variables?Lifestyle and family history may also effect the heart.
14Single-blind & Double-blind Procedure Evaluating TherapiesSingle-blind & Double-blind ProcedureIn evaluating drug therapies, patients and/or experimenter’s assistants should remain unaware of which patients had the real treatment and which patients had the placebo treatment.OBJECTIVE 13| Explain why random assignment and double-blind procedure build confidence in research findings.Placebo EffectExperimenter EffectPsychology 7e in Modules
15Evaluating Therapies Random Assignment Assigning participants to experimental (Breast-fed) and control (formula-fed) conditions by random assignment minimizes pre-existing differences between the two groups.Sometime research participants out of enthusiasm or personal beliefs can affect the out come of an experiment. To control for such affects, a double-blind procedure is used, in which the participants and the experimenter’s assistants are not aware of which participants got real treatment and who got placebo.Psychology 7e in Modules
16Hawthorne Effect But even the control group may experience changes. Just the fact that you know you are in an experiment can cause change.Whether the lights were brighter or dimmer, production went up in the Hawthorne electric plant.
17Experimentation Review A summary of steps during experimentation.
18Let’s do an experiment. Hypothesis: The red pill will reduce anxiety. We operationalize the definition of anxiety to mean those whose doctors claim they suffer from anxiety.We find 100 people who fit the operationalized definition
19We randomly assign half the men to the experimental group and half the men to the control group. (Same with women).I, the researcher, do not know which group will receive the medication and which will receive the placebo. That means this is a double-blind experiment. This will reduce experimenter bias.
20The experimental group will receive the actual medication The experimental group will receive the actual medication. (medication - independent variable)The control group will receive a sugar pill (placebo).The research team will ask all participants to measure their level of anxiety on a scale from 1 to 10. (Anxiety -dependent variable).The control group will usually report a decrease in anxiety even though they received no medicine. This is called the placebo effect.
21Consider the confounding variables Consider the confounding variables. This is the stuff that will screw up your experiment.Ex: what if the control group had a mean age much less than the experimental group? What if the 2 groups had a different percentage of women?
22Our original hypothesis was: the red pill will reduce anxiety by 40%. Results: The experimental group reported a mean of 10% reduction in anxiety versus a 5% reduction for the control group.Theory: After several replications, the medicine has no significant effect on anxiety.
23Reliability and validity? A finding is reliable if it can be replicated. If subsequent studies show that the red pill reduces anxiety then the findings are reliable, thus supporting the hypothesis.A study is valid if it measures what it is supposed to measure. If our experiment measured hypertension instead of anxiety, then the test in invalid, even if it is reliable.
24Descriptive Methods A.Case studies B. surveys Type 2 Research methodsWhat is going on in this picture?A.Case studiesB. surveysC. naturalistic observationWe cannot say exactly, but we can describe what we see.
25A. Case Studies A detailed picture of one or a few subjects. Tells us a great story…but is just descriptive research.Does not even give us correlation data.The ideal case study is John and Kate. Really interesting, but what does it tell us about families in general?
26B. Survey Method: The Bad Low Response RatePeople Lie or just misinterpret themselves.Wording EffectsEx. Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid)How accurate would a survey be about the frequency of diarrhea? Homosexuality? Infidelity?
27Survey Random Sampling If each member of a population has an equal chance of inclusion into a sample, (unbiased).If the survey sample is biased, its results are not valid.The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.
28False Consensus Effect SurveyFalse Consensus EffectA tendency to overestimate the extent to which others share our beliefs and behaviors.
29C. Naturalistic Observation Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation.OBJECTIVE 7| Identify the advantages and disadvantages of naturalistic observation in studying behavior and mental processes.Courtesy of Gilda MorelliPsychology 7e in Modules
30Longitudinal studies Cross-sectional study A subject is studied for a long long long time.Twins separated at birth are surveyed at ages 5, 10, 15, 20, 30 years.Cross-sectional studyDifferent groups of people are compared and contrasted.Ex. Hispanic vs Caucasion on attitudes towards psychotherapy
31Types of Correlation Negative Correlation Positive Correlation Type 3 Research methodsNegative CorrelationThe variables go in opposite directions.Positive CorrelationThe variables go in the SAME direction.Studying and grades hopefully has a positive correlation.Heroin use and grades probably has a negative correlation.
32(positive or negative) CorrelationWhen one trait or behavior accompanies another, we say the two correlate.Indicates strengthof relationship(0.00 to 1.00)Correlationcoefficientr =+0.37OBJECTIVE 8| Describe positive and negative correlations and explain how correlational measures can aid the process of prediction.Correlation Coefficient is a statistical measure of the relationship between two variables.Indicates directionof relationship(positive or negative)Psychology 7e in Modules
33ScatterplotsPerfect positivecorrelation (+1.00)Scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.
34Scatterplots Perfect negative No relationship (0.00) correlation (-1.00)No relationship (0.00)
35Normal Distribution Which is a stronger correlation? -.13 or +.38
37ScatterplotThe Scatterplot below shows the relationship between height and temperament in people. There is a moderate positive correlation of
38Correlational MethodCorrelation expresses a relationship between two variable.Does not show causation.As more ice cream is eaten, more people are murdered.Does ice cream cause murder, or murder cause people to eat ice cream?
39Disconfirming evidence Illusory CorrelationThe perception of a relationship where no relationship actually exists. Parents conceive children after adoption.Confirming evidenceDisconfirming evidenceDo notadoptAdoptDo not conceiveConceiveOBJECTIVE 10| Describe how people form illusory correlations.Michael Newman Jr./ Photo EditPsychology 7e in Modules
41Hindsight Bias Hindsight Bias is the “I-knew-it-all-along” phenomenon. Monday Morning Quarterbacking!!!Hindsight Bias is the “I-knew-it-all-along” phenomenon.After learning the outcome of an event, many people believe they could have predicted that very outcome.OBJECTIVE 1| Describe hindsight bias and explain how it can make research findings seem like mere common sense.“Anything seems commonplace, once explained.” Dr. Watson to Sherlock Holmes.Two phenomena – hindsight bias and judgmental overconfidence – illustrate why we cannot rely solely on intuition and common sense.After the Chris Brown/Rihanna incident….my wife said she knew Chris Brown was a violent kid!!! Did she really?Psychology 7e in Modules
42Overconfidence Sometimes we think we know more than we actually know. 82% of U.S. drivers consider themselves to be in the top 30% of their group in terms of safety.Sometimes we think we know more than we actually know.AnagramHow long do you think it would take to unscramble these anagrams?WREATWATERETYRNENTRYOBJECTIVE 2| Describe how overconfidence contaminates our everyday judgments.People said it would take about 10 seconds, yet on average they took about 3 minutes (Goranson, 1978).GRABEBARGEPsychology 7e in Modules
43Order in Random EventsGiven random data, we look for order and meaningful patterns.The outcome of one toss gives no clue to the next outcome-no patternsYour chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.Psychology 7e in Modules
45Q1. Can laboratory experiments illuminate everyday life? FAQQ1. Can laboratory experiments illuminate everyday life?Ans: Artificial laboratory conditions are created to study behavior in simplistic terms. The goal is to find underlying principles that govern behavior.OBJECTIVE 21| Explain the value of simplified laboratory conditions in discovering general principles of behavior.Psychology 7e in Modules
46Q6. Is it ethical to experiment on people? FAQQ6. Is it ethical to experiment on people?Ans: Yes. Experiments that do not involve any kind of physical or psychological harm beyond normal levels encountered in daily life may be carried out.
47Animal Research Clear purpose Treated in a humane way Acquire animals legallyLeast amount of suffering possible.
48Human Research No Coercion- must be voluntary Informed consent AnonymityNo significant riskMust debrief
49Statistical Reasoning Statistical procedures analyze and interpret data allowing us to see what the unaided eye misses.Descriptive Statistics: set of methods to describe data we have collectedEx. Henry averaged 1 new cars sold for the last 3 SundaysInferential Statistics: set of methods used to make generalizations, estimates, predictionsEx. Henry never sells more than 2 cars on SundayOBJECTIVE 15| Explain the importance of statistical principles, and give an example of their use in daily life.Psychology 7e in Modules
50Describing DataA meaningful description of data is important in research.Misrepresentation may lead to incorrect conclusions.OBJECTIVE 16| Explain how graphs can misrepresent data.Psychology 7e in Modules
51Measures of Central Tendency Mode: The most frequently occurring score in a distribution.Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together.Median: The middle score in a rank-ordered distribution.OBJECTIVE 17| Describe three measures of central tendency and tell which is most affected by extreme scores.Psychology 7e in Modules
52Measures of Central Tendency A Skewed Distribution
53Central Tendency Mean, Median and Mode. Watch out for extreme scores or outliers.Let’s look at the salaries of the employees at Dunder Mifflen Paper in Scranton:$25,000-Pam$25,000- Kevin$25,000- Angela$100,000- Andy$100,000- Dwight$200,000- Jim$300,000- MichaelThe median salary looks good at $100,000.The mean salary also looks good at about $110,000.But the mode salary is only $25,000.Maybe not the best place to work.Then again living in Scranton is kind of cheap.
54Measures of VariationRange: The difference between the highest and lowest scores in a distribution.Standard Deviation: A computed measure of how much scores vary around the mean.OBJECTIVE 18| Explain two measures of variation.Psychology 7e in Modules
56Standard DeviationThe Standard Deviation (σ) is a measure of how spread out the numbers are.The formula is easy: it is the square root of the Variance. So now you ask, "What is the Variance?"VarianceThe Variance (which is the square of the standard deviation, ie: σ2) is defined as:The average of the squared differences from the Mean.In other words, follow these steps:1. Work out the Mean (the simple average of the numbers) 2. Now, for each number subtract the Mean and then square the result (the squared difference). 3. Then work out the average of those squared differences.
57Example Find out the Mean, the Variance, and the Standard Deviation. You and your friends have just measured the heights of your dogs (in millimeters):The heights (at the shoulders) are: 600mm, 470mm, 170mm, 430mm and 300mm.Mean = = 1970 =
58Deviation just means how far from the normal Now, we calculate each dog’s difference from the Mean:To calculate the Variance, take each difference, square it, and then average the result:Variance: σ2 = (-224) (-94)2 = 108,520 = 21,704Standard Deviation: σ = √21,704 = 147Standard Deviation: σ = √21,704 = 147Now we can show which heights are within one Standard Deviation (147mm) of the Mean:So, using the Standard Deviation we have a "standard" way of knowing what is normal, and what is extra large or extra small.