Human psychology is the scientific study of human behaviour and mental processes. The scientific method is a way to determine facts and control the possibilities of error and bias when observing behavior. The five methods involved in the scientific method are perceiving the question, forming the hypothesis, testing the hypothesis, drawing conclusions and reporting the results.
Psychologist use naturalist and laboratory settings to describe behaviour. Naturalistic observations involve watching people in their natural environments but have the disadvantage of lack of control. Laboratory observations involve watching people in an artificial but controlled situation, such as a laboratory.
While studying human psychology, psychologists use case studies and surveys to describe behavior. Case studies are detailed investigations of one subject, whereas surveys involve standardized questions of large group of people who represent a sample of the population of interest. Information gained from case studies cannot be applied to other cases since people responding to surveys may not always tell the truth or remember information correctly.
While studying human psychology, many techniques are involved. Correlation is a statistical technique that allows researchers to discover and predict relationships between variables of interest. Positive correlation exist when increase in one variable are matched by increases in the other variable, whereas negative correlations exist when increase in the other variable are matched by decrease in the other variable. Also, correlations cannot be used to prove cause-and-effect relationships.
Researchers use operational definitions, independent and dependent variables, experimental and control groups, and random assignments in designing an experiment for understanding more about human psychology. Experiments are tightly controlled manipulations of variables that allow researchers to determine cause-and-effect relationships. The independent variable in an experiment is the variable that is deliberately manipulated by the experimenter to see if related changes occur in the behavior or responses of the participants and is given to the experimental group. The dependent variable in an experiment is the measured behavior or response of the participants. The control group receives nothing or a placebo treatment. Random assignment of participants to groups within an experiment helps to control for individual differences both within and between the groups that might otherwise interfere with the experiments outcome. There are placebo and experimenter effects. Experiments in which the subjects do not know if they are in the experimental or control groups are single blind studies, whereas experiments in which neither the experimenters nor the subjects know this information are called double blind studies.