CHAPTER 2 PSYCH 100 PSYCHOLOGICAL RESEARCH • We cannot rely on our intuitions about psychological phenomena. • Our methods of thinking are subject to human error and bias. • Need to have a better reasoning processes. • We need to rely on scientific processes and critical thinking to discover the truth about the mind and how it works. • Scientific knowledge is empirical: It is grounded in objective, tangible evidence that can be replicated. • While behavior is observable, the mind is not. • If someone is crying, we can see behavior: • The reason for the behavior is more difficult to determine Scientific Method • A theory is a well-developed set of ideas that propose an explanation for observed phenomena. • A hypothesis is a testable prediction about how the world will behave if our idea is correct, and it is often worded as an if-then statement (e.g., if I study all night, I will get a passing grade on the test). Scientific Method • Theories and hypotheses are tested in the form of empirical observations, and those empirical observations lead to more ideas that are tested, and so on. • In deductive reasoning, ideas are tested against the empirical world (decreasing) • In inductive reasoning, empirical observations lead to new ideas (increasing) Scientific Method Developing a Research Question Drawing on theory, observations, experiences, or common beliefs to formulate a researchable question Forming a Hypothesis Gathering Evidence Drawing Conclusions Reframing the question so that it becomes a specific prediction that can be tested through research Testing the hypothesis Using statistical methods of analysis to determine whether the data support the hypothesis Scientific Method • Theories and hypotheses are tested in the form of empirical observations, and those empirical observations lead to more ideas that are tested, and so on. • In deductive reasoning, ideas are tested against the empirical world (decreasing) • In inductive reasoning, empirical observations lead to new ideas (increasing) Scientific Method Scientific Method WHY IS RESEARCH IMPORTANT? • Theory: A set of statements that explain and organize observations and lead to testable predictions (hypotheses) – Parental Investment Theory: The gender that invests the most in reproduction will evolve to be choosiest in mate selection. The gender that invests the least will evolve to be more opportunistic in mating. • Explains big differences between genders with likelihood of adultery & promiscuity. WHY IS RESEARCH IMPORTANT? • Hypothesis: A testable prediction derived from a theory –States what observations would support a theory and what observations would go against it –E.g., Men should be more likely than women to consent to sex when propositioned by an attractive stranger (tested by Clark and Hatfield, 1989) • Replicated many times to show consistency in behavior. WHY IS RESEARCH IMPORTANT? • Not all theories in psychology have been testable • E.g., Freud’s theory that all dreams are attempts at wish fulfillment – E.g., dream of a house and it may represent worries about security as well as one’s appearance to the rest of the world. – If the person denies it that is consistent with the theory because of repression. If they agree with it, it is also consistent Hypothesis: Students who study over a span of 3 weeks before a test perform better than those who wait until the night before Method Data Collection Analysis Report Findings APPROACHES TO RESEARCH • Descriptive –Observational techniques –Case studies –Survey research –Correlational studies • Explanatory –Experiments APPROACHES TO RESEARCH • Definition: Descriptive research is the systematic, objective observation of people • Goal: To provide a clear, accurate picture of people’s behaviors, thoughts, feelings and attributes – It is a good way to come up with theories • Limitation: Does not support causal claims so we cannot understand why something was done APPROACHES TO RESEARCH A case study is an in-depth report on a single individual (or a small group) that may include interviews, psychological testing, and observations. It can provide a rich source of information but is limited as a scientific investigation. Limitations: • Possible problems if rely on people’s memories of past experiences • People may withhold important information • Interviewer biases or expectations may influence people’s reports or recollections • Cannot generalize results to others APPROACHES TO RESEARCH • Naturalistic observation is when a researcher engages in careful observation of behavior without intervening directly with the subjects. • This method allows researchers to study behavior under conditions that are less artificial than experiments, but it does lack the control of a laboratory setting. • It can be particularly useful for studying animals in their natural habitats. • Limitations include potential observer bias, which can be countered by using pairs of observers. APPROACHES TO RESEARCH • Surveys use questionnaires to find out about specific aspects of people’s backgrounds, attitudes, or opinions. • Calls for the use of a sample, which is a representative subset of a larger population. A representative sample is obtained using a random sampling approach. • Can be limited by the social desirability bias, participants answer with responses that they think will make them look good but may not be truly honest. ANALYZING FINDINGS • Correlational Method • Two variables are measured to determine if they are related – A variable is any factor that can take on more than one value (e.g., height, age, GPA, extraversion level) • Benefits of correlational research: – Offers clues to underlying causes, but does not allow for causeand-effect conclusions. – Can identify groups of people at high risk for physical or behavioral problems. – Increases understanding of relationships between variables. Negative Correlation High -1.00 -.90 Moderate -.80 -.70 -.60 -.50 Positive Correlation Low -.40 -.30 -.20 -.10 Low 0 .10 Moderate .20 .30 .40 .50 High .60 .70 .80 .90 1.00 Strength of Relationship Increasing Increasing • The correlation coefficient is a numerical measure of the degree of relationship between two variables. • The size of the correlation coefficient varies between zero and + or - one. It is the size of the correlational coefficient that indicates the strength of the association between two variables. The sign (positive or negative) indicates the direction of correlation. • Zero is no relationship, one is a perfect relationship. Closer to one is stronger and closer to zero is weaker. X Generally speaking, people with higher levels of education tend to earn higher incomes. Y Generally speaking, the longer a person is deprived of sleep, the less alert the person is likely to be. • Correlations very rarely appear in a straight line, but rather will “cluster” around a positive or a negative curve. • Above demonstrates the variability in observations that still indicate a positive correlation (between income and years of education) and a negative correlation (between alertness & hours of sleep). If we find a correlation, what conclusions can we draw from it? What if we find the following result from a Correlational Study: There is a positive correlation between two variables: ➡Ice cream sales & violent crime How do we explain this? Lesson: Correlation is not Causation! “People who floss more regularly have less risk of heart disease.” “People with bigger feet tend to be taller.” If these data are from a survey, can we conclude that flossing might prevent heart disease? Or that people with heart-healthy habits also floss regularly? Does that mean having bigger feet causes height? ANALYZING FINDINGS • Investigators use the experimental method to determine whether there is a causal relationship between the independent (manipulated) variable(s) and the dependent (observed/measured) variable(s). • Allows for investigation of cause-andeffect relationships (causal) • Does manipulating one variable (independent) cause a change in another variable (dependent)? • In the experimental method, the researchers manipulate an independent variable and observe the effects on a dependent variable under controlled conditions. • The independent variable (IV) is manipulated/controlled by experimenter. • The dependent variable (DV) is what is measured and thought to be affected by the independent variable. • The experimental group is those who receive special treatment. • The control group consists of similar participants who do not receive treatment given to experimental group. • Operational definitions define the variables and procedure(s) used to investigate them. • Random assignment is used to randomly assign the participants to the control and/or experimental groups to get rid of outside influences. Participants Randomly Assigned Independent Variable: Control group Independent Variable: Experimental group(s) Measure Dependent Variable Is there a significant difference between the different groups? ANALYZING FINDINGS Level of Perceived Pain = Dependent Variable Experimental Group Independent Variable Control Group No Treatment • An example of experimental research would be testing morphine for effectiveness using the absence of pain as the dependent variable. • The control group allows the researcher to isolate the effects of the independent variable. • Because the two groups are alike in every way except for the independent variable, any difference between the groups can be attributed to the independent variable (morphine). Placebo effects – Do our expectations influence the outcomes we experience? • Placebos can be used with a control group so that the participants “think” they are receiving a treatment. If they then show a change in the when individuals are given a medication (placebo) in an experiment, their expectations about the treatment may produce a placebo effect. • For example, if people are told they are drinking an alcoholic beverage, but are given a virgin margarita instead, they may begin acting intoxicated because of a placebo (expectancy) effect. • Single-blind studies are used when the participants are unaware of which group they have been assigned to. • Double-blind studies are used when neither the researcher nor the participants know which participants are in which group. Ethics • Reliability is the ability to consistently produce a given result. In the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. • Validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. • Researchers strive to use instruments that are both highly reliable and valid. Ethics • Psychological organizations – too many to list! Different organization by sub-field… • Such a large discipline we need governing! • American Psychological Association (APA) • Association for Psychological Science (APS) APA Style Ethics • Code of ethics • For research & for therapy • Ethics review committees (IRBs) • Important ethical requirements • Informed consent • Confidentiality • Ethical guidelines for animal research Thank you: Start reading your next chapter!