RESEARCH METHODS IN PSYCHOLOGY

Theory:

An explanation using an integrated  set of principles that organizes observations and predicts behaviors or events.

Hypothesis:

 A testable prediction, often implied by a theory.

Operational definition: 

A statement of the procedures (operations) used to define research variables. For example, human intelligence may be operationally defined as “what an intelligence test measures.”

Replication: 

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.

i.                    Case study: a technique in which one person is studied in depth in the hope of revealing universal principles. Some examples: Much of our early knowledge about the brain came from case studies of individuals who suffered a particular impairment after damage to a certain brain region. Jean Piaget taught us about children’s thinking after carefully observing and questioning only a few children. Studies of only a few chimpanzees have revealed their capacity for understanding and language. Intensive case studies are sometimes very revealing. They show us what can happen, and they often suggest directions for further study.

But individual cases may mislead us if the individual is atypical. Unrepresentative information can lead to mistaken judgments and false conclusions.

ii.                  Naturalistic Observation: A second descriptive method records behavior in natural environments. These naturalistic observations range from watching chimpanzee societies in the jungle, to unobtrusively videotaping (and later systematically analyzing) parent-child interactions in different cultures, to recording racial differences in students’ self-seating patterns in a school lunchroom. Like the case study, naturalistic observation does not explain behavior. It describes it. Nevertheless, descriptions can be revealing. We once thought, for example, that only humans use tools.

iii.                The Survey : A survey looks at many cases in less depth. A survey asks people to report their behavior or opinions. Questions about everything from sexual practices to political opinions are put to the public. But asking questions is tricky, and the answers often depend on the ways questions are worded and respondents are chosen. Wording Effects Even subtle changes in the order or wording of questions can have major effects. But it’s not always possible to survey everyone in a group. So how do you obtain a representative sample—say, of the students at your college or university? How could you choose a group that would represent the total student population, the whole group you want to study and describe? Typically, you would seek a random sample, in which every person in the entire group has an equal chance of participating. Political pollsters sample voters in national election surveys just this way.

iv.                Correlation Studies: Describing behavior is a first step toward predicting it. Naturalistic observations and surveys often show us that one trait or behavior is related to another. In such cases, we say the two correlate. A statistical measure (the correlation coefficient) helps us figure how closely two things vary together, and thus how well either one predicts the other. Knowing how much aptitude test scores correlate with school success tells us how well the scores predict school success.

Saying that a correlation is “negative” says nothing about its strength or weakness. A correlation is negative if two sets of scores relate inversely, one set going up as the other goes down. Correlation coefficient a statistical index of the relationship between two things (from −1 to +1).

v.                  Experimental Method: experiment is a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors. Experimental group in an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable. Control group in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment. Random assignment assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between those assigned to the different groups. Double - blind procedure an experimental procedure in which 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. placebo [pluh - SEE-bo; Latin for “I shall please”] effect experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent. Independent variable the experimental factor that is manipulated; the variable whose effect is being studied. Confounding variable a factor other than the independent variable that might produce an effect in an experiment. Dependent variable the outcome factor; the variable that may change in response to manipulations of the independent variable.