Types of Experiments
Conventional experiments require that subjects be divided into two groups: an experimental group and a control group. The experimental
group contains the subjects who are exposed to an Independent variable (the experimental condition) to study its effect on them. The control grOlip contains the subjects who are not exposed to the independent variable. The members of the two groups are matched for similar characteristics so that comparisons may be made between the groups. In the simplest experimental design. subjects are (l) pretested (measured) in terms of the dependent variable in the hypothesis. (2) exposed to a stimulus representing an independent variable. and (3) post-tested {remeasured) in terms of the dependent variable. The experimental and control groups are then compared to see if they differ in relation to the dependent variable. and the hypothesis stating tl e relationship of the two variables is confirmed or rejected,
In a laboratory experiment, subjects are studied in a closed setting so that researchers can maintain as much control as possible over the research. For example. if you wanted to examine the influence of the media on attitudes regarding suicide. you might decide to use a laboratory experiment. Sociologist Arturo Biblarz and colleagues (1991) designed a laboratory study to investigate the effects of the media on people's attitudes toward suicide. Researchers showed one group of subjects a film about suicide. showed a second group a film abort violence. and showed a third a film containing neither suicide nor violence. Some evidence was found that media exposure to suicidal acts or violence may arouse an emotional state favorable to suicidal behavior, especially in those persons already "at risk" for suicide. Not all experiments occur in laboratory settings. Natural experiments are real-life occurrences such as floods and other disasters that provide researchers with "living laboratories." Sociologist Kan Erickson (1976) studied the consequences of a deadly 1972 rood in Buffalo Creek. West Virginia. and found that extensive disruption of community ties occurred. Natural experiments cannot be replicated because it is impossible to re-create the exact conditions, nor would we want to do so.
