Scientific methodology may be the most important human development of the past one thousand years. Thanks to this method, observation is no longer constrained by the limits and biases of human thinking. Psychologists no longer have to rely on the often fallacious procedure of casual observation. Now they can explore human behavior and mind systematically, using objective means to identify real phenomena.
This demonstration will help you appreciate the inadequacy of casual observation. Try to answer the following questions that are based on everyday observations:
Hopefully you can see the need for systematic research as opposed to casual observation that can lead to some of the erroneous "common sense" conclusions that were explored in the introduction to chapter 1.
Introduction to Psychology : Read chapter 2, sections 2.1 and 2.2 through the material on correlation.