Psychology Chapter 2 Sections 4 and 5

Chapter 2 Section 4:  The Experimental Method

  • The method researchers use to answer questions about cause and effect is the experiment.
  • Experiment:  a controlled scientific procedure to determine whether certain variables manipulated by the research have an effect on other variables.
  • Limitations to the experimental method include:
    • 1. The conditions created in an experiment may not accurately reflect conditions in real life.
    • 2.  By their nature they must simplify things in order to yield useful information about cause and effect.
  • Variables:  factors that are measured or controlled in a scientific study. (Factors that vary or change)
  • Independent variable:  the factor that is manipulated by the researcher to determine its effect on another variable.
    • In our experiment the candy was the independent variable.
  • Dependent Variable:  In an experiment, the factor that is being measured and that may change in response to manipulations of the independent variable.
    • In our experiment our score on the test was the dependent variable.
  • Another way to look at independent and dependent variables:










What you do

What happens

  • Ideal experiments use experimental and control groups.
    • Control Group:  in an experiment, the group that does NOT receive treatment.
      • In our experiment the control group was test 1 (the test you took without the candy)
    • Experimental Group: in a study, the participants who receive treatment.
      • In our experiment the experimental group was test 2 (the test you took with the candy)
  • It is important that all other conditions are held constant for both the experimental and the control group because it makes it possible for researchers to conclude that the experiments results are caused by the treatment, and not something else.
    • Controlled Experiment:  an experiment that used both a control group and an experimental group to determine whether the independent variable influences the behavior, and if so, how it does so
  • The Placebo effect-our expectations affect what happens to us.
  • Placebo:  An inert substance used in controlled experiments to test the effectiveness of another substance.
    • In our experiment the placebo was the candy.
  • Expectations can create bias toward certain points of view.  Researchers must come up with ways to keep participants unaware of treatment they are receiving.
    • Single-blind study:  a study in which the participants are unaware whether they are in the control group or the experimental group.
      • Our experiment was a single-blind study. (I did not tell you if you were in the control or experimental group)
    • Double blind study:  an experiment in which neither the participant nor the researcher knows whether the participant has received the treatment or the placebo.
      • These are helpful because not only do participants have expectations, but so do the researchers.  The people who measure the effects remain unbiased.

Ethics:  Rules and standards for proper and responsible behavior

  • Psychologists follow ethical standards to promote the dignity of the individual, foster human welfare, and maintain scientific integrity.
  • Psychologists try to lesson human suffering, not cause it.
  • Ethical standards prevent scientists from undertaking research or treatments that will be harmful to human participants.
  • Ethical guidelines have been established by the American Psychological Association (APA), a scientific and professional organization of psychologists.

Research with people:

  • Ethical standards limit the type of research that psychologists may conduct.
  • Psychologists may not violate the ethical principle that study participants must not be harmed.
  • What are the ethical standards researchers must adhere to?
    • The APA guidelines provide a number of provisions that detail what is needed to  make a study ethical.
      • They include 2 important principles:
        • Confidentiality
          • Records of research participants must be kept confidential or private.
          • Psychologists respect people’s rights to privacy.
          • Confidentiality helps participants to disclose true information and feelings when they know that what they say will be kept confidential
          • Question:  Is it okay for a psychologist to disregard confidentiality?
            • Yes in order to protect the well-being of the client or the other people.
            • This is usually rare, and psychologists often have a lot to consider whether or not breaking confidentiality is the right thing to do.
        • Informed consent:  an agreement by an individual to participate in research after receiving information about the purpose of the study and the nature of the treatment.
          • The APA has distinct restrictions against research studies that could pose a serious threat to the physical or psychological health of participants, or that may have long-term irreversible effects on them.
          • Some worthwhile studies may cause participants to experience some discomfort or other short-term negative effects.
          • To help avoid situations in which people volunteer to participate in research without knowing that such effects are possible, the APA generally requires that participants provided informed consent.
          • This gives participants some information and the opportunity to choose which gives some degree of control and can make participation less stressful.
  • Deception:
    • Some psychological experiments cannot be run without deceiving people.
    • Psychologists have debated the ethics of deceiving participants in research.
    • According to the APA psychologists may use deception only under specified conditions:
      • When they believe the benefit of research outweigh its potential harm.
      • When they believe that the individuals would have been willing to participate if they had understood the benefit of the research.
      • When participants receive an explanation of the study after it has occurred.
  • Explaining what happened in the study once it is over helps avoid misunderstandings about the research.
    • It can also reduce participants’ anxieties and let the participants maintain their dignity.

Research with Animals

  • Most studies that use animals do not harm the animals at all, however sometimes they do conduct research that could be harmful to animals.
  • Animals are used in place of people for ethical reasons or to avoid harming humans.
  • Psychologists use animals only when there is no alternative and when they believe that the potential benefits outweigh the harm.


Ethics in Using Data

  • Another area in which psychologists follow strict rules about ethics is in how they produce, store, and present their data.
  • Psychologists need to be as objective as possible in planning their study, collecting their data, and analyzing it.
  • Without this there could be bias in favor of their hypothesis.
  • When information collected by researchers contradicts their hypothesis they must be willing to discard their hypothesis in light of evidence.