Psychology is often thought of as a field primarily concerned with emotions, thoughts, or inner states. And while much of psychology deals with these topics, you have also learned that the field is very large, and is officially defined as a scientific study of behavior and mental processes.

One of the first areas where psychology developed into a truly scientific understanding of mental processes was in the realms of sensation and perception. Before a person can form thoughts and emotions about the outside world, a more basic question arises: how does someone even experience the outside world? What things can a person hear, see, taste and touch, and what remains hidden from perception?

These questions about how humans get and interpret information about the outside world form one of the fundamental areas of study within psychology. In this topic, you will learn about some of the basic concepts of sensation.

Essential Questions

• How do sensation (bottom-up processing) and perception (top-down processing) interact to help you detect signals from the surrounding environment?
• What are absolute and difference thresholds and how are they measured?
• What is sensory adaptation and what are some common examples of this phenomenon?
• How does signal detection theory help explain why psychological factors can alter your likelihood of perceiving messages, dangers, or alarms?