Introduction to Psychology

Introduction to Psychology The independent variable is viewed as the cause and the dependent variable as the effect. It is possible that subjects in an experimental group could behave differently than they normally would, because they know they are being exposed to special treatment. This is called the placebo effect. In order to determine the extent to which this might be happening, the control group subjects are sometimes told that they too are receiving a special treatment or drug, even when they are not. This fake special treatment or drug is called a placebo. If subjects don’t know whether or not they are receiving the placebo, the experiment is called a blind study. It is possible that experimenters can unwittingly influence results by knowing which subjects are receiving which treatment. Therefore, in a double-blind study, even the experimenters do not know if they are delivering the placebo or the drug. Although the experimental approach is a powerful tool for examining causality, researchers must avoid errors that can lead to faulty conclusions. Tests Psychologists develop and use specialized tests to measure many types of variables. For example, personality tests, which assess personality traits, often contain questions that ask how a person typically feels or behaves. Other psychological tests consist of performance tasks. For example, intelligence tests may ask people to assemble objects or solve arithmetic problems. Neuropsychological tests help diagnose normal and abnormal brain functioning by measuring how people perform mental and physical tasks, such as recalling lists of words or manipulating objects. To enhance learning and chances of performing well on tests, one can apply scientific psychological principles regarding time management, strategies for studying more effectively, test preparation strategies, and techniques for taking tests. Statistical Methods Statistics are woven into the fabric of modern life, and they are integral to psychological research. Typically, it is difficult to make sense out of the data collected by examining the individual score of each participant. Descriptive statistics allow us to summarize and describe the characteristics of a set or distribution of data. Descriptive- Two types of descriptive statistics are measures of central tendency and measures of variability. Measures of Central Tendency - Given a set of data, measures of central tendency address the question “What is the typical score?” One measure, the mode, is the most frequently occurring score in a distribution. A second measure is the median, the point that divides a distribution of scores in half when those scores are arranged in order from lowest to highest. Finally, the mean is the arithmetic average of a set of scores. Because the mean takes all the information in a set of scores into account, it is the most commonly used measure of central tendency.

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