Page 221 - Understanding Psychology

Sensation
Reader’s Guide
Exploring Psychology
Discovering a New World
Helen Keller had been blind and deaf since she was two years old. For the next four years, Helen was “wild and unruly.” Then when she was six, Anne Sullivan, a teacher, entered her life. Using the sense of touch as the link between their two worlds, Anne tried again and again, by spelling words into Helen’s hand, to make Helen grasp the connection between words and the things they stood for. The breakthrough came one day as Anne spelled the word water into Helen’s hand as water from a spout poured over it. “I stood still, my whole attention fixed upon the motions of her fingers,” Helen remem- bered. “Suddenly I felt . . . a thrill of returning thought; and somehow the mys- tery of language was revealed to me.”
—adapted from ABC’s of the Human Mind, Reader’s Digest, 1990
s Main Idea
Sensations allow humans to under- stand reality. Sensations occur any- time a stimulus activates a receptor.
s Vocabulary
• sensation
• perception
• psychophysics
• absolute threshold
• difference threshold
• Weber’s law
• signal-detection theory
s Objectives
• Describe the field of study known as
psychophysics.
• Define and discuss threshold, Weber’s
law, and signal detection.
From that day forward, Helen “saw” the world in a new way. She discovered new ways to experience her world. “Occasionally, if I am very fortunate, I place my hand gently on a small tree and feel the happy quiver of a bird in full song.” Helen had entered a world of sensations after she began organizing the stimuli in her world. Try it yourself.
In the next few seconds, something peculiar will start hap pening to the material youa rereading. Iti soft ennotre alized howcom plext hepro- ces sof rea ding is.
Chapter 8 / Sensation and Perception 207