Introduction to Psychology

Critical Thinking, Research & Ethics

Thinking Critically w/Psychological Science

• Critical Thinking – thinking that does not blindly accept arguments &

conclusions• examines assumptions• evaluates evidence

• Limits of Intuition and Common Sense– Hindsight Bias

• tendency to believe, after learning an outcome, that one would have foreseen it

• the “I-knew-it-all-along” phenomenon– Overconfidence

• we tend to think we know more than we do• Theory

– an explanation using an integrated set of principles that organizes & predicts observations

• Hypothesis – a testable prediction

• The Scientific Method– Test a statement using research & experimentation, refine or

generate new hypothesis, leading to a generalizable theory

• Experiment – designed to test a hypothesis = prediction about a

cause-effect relationship between two or more conditions or variables

– a research method in which the investigator manipulates one or more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable) while controlling other relevant factors by random assignment of subjects

• Experimental Condition/Group– the condition of an experiment that exposes

subjects to the treatment (one version of the independent variable)

• Control Condition/Group– the condition of an experiment that contrasts with

the experimental treatment – serves as a comparison for evaluating the effect of

the treatment

Experimental Research

Continued…

• Random Assignment– assigning subjects to experimental & control conditions by

chance– minimizes pre-existing differences between those assigned

to the different groups• 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

Continued…

• Potential Problems:– selection bias = assignment of subjects to experimental or

control groups in such a way that systematic differences are present between the groups

• Solution: use random assignment to guarantee that all subjects have an equal probability of being placed in any of the groups

– placebo effect = subject’s response to a treatment is due to subject’s expectations about the treatment rather than the actual treatment itself

– experimenter bias = researcher’s preconceived notions in some way influence the subjects’ behavior and/or the interpretation of experimental results (self-fulfilling prophecy)

• Solution: use double-blind technique so neither the subjects nor the researcher knows who is in the experimental or control groups until after the results are gathered

Continued…

• Advantage of Experimental Research:– ability to reveal cause-effect relationships

• Disadvantage of Experimental Research:– in many areas of interest, the method is unethical or

not possible (endangers humans psychologically or physically)

• Descriptive Research = research methods that yield descriptions of behavior rather than causal explanations

• Case Study– single person or small group is studied in great depth

over an extended period of time--uses observation, interviews, psych testing

• purpose is to provide a detailed description of some behavior or disorder

– ex. unusual psychological or physiological disorders

• + sometimes provides the foundation for psychological theories

• - not always generalizable to larger groups or different cultures

Other Types of Research (Descriptive)

• Survey– interviews and/or questionnaires are used to gather

information about attitudes, beliefs, experiences, or behaviors of a group of people

• ex. Drug use & sexual behavior– sample = portion of a population selected for study &

from which generalizations are made about the larger population

– representative sample = sample that includes important subgroups in same proportion as they are found in the larger population

– + can provide highly accurate information about a large number of people

– - people can give false information because of faulty memory or desire to please the interviewer or because they want to mislead the researcher

Other Types of Research (Descriptive)

• Naturalistic Observation– observing & recording behavior in naturally

occurring situations without trying to manipulate or control the situation

• + more spontaneous & natural than lab• - can’t speed up or slow down process

• Laboratory = observation in a controlled setting with precise equipment to measure responses– ex. Sleep studies– - more artificial & contrived conditions than in nature– + researcher has a lot of control over the conditions

Continued…

• Correlational Research– used to determine the relationship between two

characteristics, events, or behaviors – correlation coefficient = numerical value that indicates

the strength and direction of the relationship between variables (+1 to -1)

– Positive Correlation = as independent variable increases, the dependent variable increases (or vise versa)

– Negative Correlation = as independent variable increases, the dependent variable decreases (or vise versa)

– Zero Correlation = no relationship between the variables– Illusory Correlation = the perception of a relationship

where none exists (ex. …)– NOTE : Correlation doesn’t = causation

• Three possible cause-effect relations when depression is correlated with low self-esteem

– Depression causes low self-esteem…or…– Low self-esteem causes depression…or…– Distressing events or biological predisposition

causes low self esteem & depression

Continued…

• Psychological Testing– personality, intelligence, aptitude, etc.– used to…

• evaluate or compare individuals• measure changes in behavior• make predictions about behavior• provide information in educational decision making,

personnel selection, and career guidance

Continued…

Ethics: Human Research

• APA Guidelines:

– Humans must the leave the experiment unharmed.

– Openness & honesty are essential.

– Subjects must always have the right to decline participation in experiment.

– Undesirable consequences must be removed before the subject is released from the study.

• Deception was involved in 40% of experiments in the 1970s.

• Debriefing = designed to erase harmful effects of deception in experiments.

Ethics: Animals

• Researchers must do everything possible to minimize discomfort, pain, & illness in animal subjects.

• Animal rights advocates want an immediate end to animal use

– Break into labs, free the animals, destroy records, wreck equipment

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