Myers’ PSYCHOLOGY (7th Ed) Chapter 1 Thinking Critically with Psychological Science James A. McCubbin, PhD Clemson University Worth Publishers

The Need for Psychological Science Psychologists, like all scientists, use the scientific method to construct theories that organize observations and imply testable hypotheses

The Need for Psychological Science  Hindsight Bias  we tend to believe, after learning an outcome, that we would have foreseen it  the “I-knew-it-all-along” phenomenon  Overconfidence  we tend to think we know more than we do

The Need for Psychological Science  Critical Thinking  thinking that does not blindly accept arguments and conclusions  examines assumptions  discerns hidden values  evaluates evidence The Amazing (James)Randi- Skeptic

The Scientific Method  Theory  an explanation using an integrated set of principles that organizes and predicts observations  Hypothesis  a testable prediction

The Need for Psychological Science

 Operational Definition  a statement of procedures (operations) used to define research variables

The Need for Psychological Science  Replication  repeating the essence of a research study to see whether the basic finding generalizes to other participants and circumstances

Description Psychologists describe behavior using case studies, surveys, and naturalistic observation

Description Case Study  Psychologists study one or more individuals in great depth in the hope of revealing things true of us all Is language uniquely human?

Description  Survey  technique for ascertaining the self-reported attitudes or behaviors of people  usually by questioning a representative, random sample of people  Random Sample  a sample that fairly represents a population because each member has an equal chance of inclusion

Description  False Consensus Effect  tendency to overestimate the extent to which others share our beliefs and behaviors  Population  all the cases in a group, from which samples may be drawn for a study

Description  Naturalistic Observation  observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

Correlation  Correlation Coefficient  a statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other Correlation coefficient Indicates direction of relationship (positive or negative) Indicates strength of relationship (0.00 to 1.00) r = +.37

Correlation  Scatterplot  a graphed cluster of dots, each of which represents the values of two variables  the slope of the points suggests the direction of the relationship  the amount of scatter suggests the strength of the correlation

Correlation Perfect positive correlation (+1.00) No relationship (0.00)Perfect negative correlation (-1.00) Scatterplots, showing patterns of correlations

Correlation Height and Temperament of 20 Men Subject Height in Inches Temperament Subject Height in Inches Temperament

Correlation Scatterplot of Height and Temperament Temperament scores Height in inches

Illusory Correlation  Illusory Correlation  the perception of a relationship where none exists  For example: more babies are born during a full moon.

Experimentation  Experiment  an investigator manipulates one or more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable)  Used to illustrate cause and effect

Experimentation  Placebo  an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent  Double-blind Procedure  both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo  commonly used in drug-evaluation studies

Experimentation  Experimental Group  the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable  Control Group  the condition of an experiment that contrasts with the experimental treatment  serves as a comparison for evaluating the effect of the treatment

Experimentation  Random Assignment  assigning participants to experimental and control conditions by chance

Experimentation  Independent Variable  the experimental factor that is manipulated  the variable whose effect is being studied  Dependent Variable  the experimental factor that may change in response to manipulations of the independent variable  in psychology it is usually a behavior or mental process

zConfounding variable-are factors affecting the dependent variable in an experiment. zRandom variables-are uncontrollable factors that could affect the dependent variable in an experiment. zExperimenter bias-occurs when a researcher encourages subjects to respond in a way that supports their hypothesis.

Experimentation

STATISICAL ANALYSIS zStatistical analyses are used to interpret research results. zDescriptive statistics describe data. zInferential statistics are used to drawn conclusions and make inferences about what the data mean.

Measures of Central Tendency- Descriptive Statistics  Mode  the most frequently occurring score in a distribution  Mean  the arithmetic average of a distribution  obtained by adding the scores and then dividing by the number of scores  Median  the middle score in a distribution  half the scores are above it and half are below it

 Range  the difference between the highest and lowest scores in a distribution  Standard Deviation  It measures the average difference between each score and the mean of the data set or a measure of how much scores vary around the mean  Statistical Significance  a statistical statement of how likely it is that an obtained result occurred by chance

ETHICS z1. Informed consent z2. Protected from harm & discomfort z3. Confidential z4. Debriefed