Lecture: Research Methods in Psychology
Reading Assignment 4:

Experimental/ Descriptive Research (pp.38-48)

Click for objectives for Reading Assignment 4
The fourth reading assignment introduces students to the three research approaches used to scientifically investigate human behavior. Entire chapters and books have been written about each of the three approaches, which include Experimental Research, Descriptive Research, and Correlational Research.
The first and most complicated type of research study is Experimental Research. There are Six Steps for Conducting Experimental Research. In summary, the researcher chooses an Independent Variable and exposes participants in the experiment to different variations of it to determine if it has an effect on human Behavior. In simple experiments, the different variations of the Independent Variable are the same as the Condition. In some experiments, the Independent Variable is not presented to a group of participants (i.e., the Control Group) and they are compared to those that were exposed. The researcher observes the Dependent Variable and measures it to determine if the different variations produce different results.

Experimental Research is unique in that it is the only type of research that permits the researcher to make inferences about cause and effect. This is only possible because it controls for Confounding Variables. To ensure that researcher and/or participants do not bias the results of the experiment, some researchers conduct a Single Blind Study or Double Blind Study. Blind studies serve to minimize potential Demand Characteristics when the participants are unaware of the nature of the experiment and can minimize Placebo Effects.

Descriptive Research is an alternative to Experimental Research; however, it cannot control for Confounding Variables. There are three forms of Descriptive Research: Naturalistic Observation, the Case Study, and Survey Research. The Questionnaire is a tool that is essential when conducting Survey Research, as it can be used very intimately, as with an Interview, or very impersonally, as with Survey.

The last option when conducting research on human behavior is Correlational Research. This last approach uses a mathematical formula, referred to as an Inferential Statistic, that can provide much more information about collected data than a Descriptive Statistic. The mathematical formula is used to determine the extent that two or more variables are related to one another. The correlation coefficient is an inferential statistic that can range in value from negative one (-1.0) to positive one (1.0), with most resulting values being somewhere in the middle. Three resulting values can be categorized as one of three types of correlations: Positive Correlation, Negative Correlation, and Zero Correlation.


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