Topic 4

CHAPTER 4: SENSATION AND PERCEPTION

OVERVIEW
In this chapter we explore sensation and perception, the vital processes by which we connect with and function in the world. We first examine vision, the sense about which scientists know the most. We then investigate the nature of hearing, the skin senses, taste, smell, and the kinesthetic and vestibular senses. Finally, we trace the connections between our senses and health and wellness.

GAME PLAN

READ	Chapter 4: Sensation and Perception
GO TO CONNECT	Complete the LearnSmart Exercises for Chapter 4 Complete the Interactive Exercises for Chapter 4 Look at the web links for Chapter 4
STUDY	PowerPoint Slides Review textbook chapter Review TopHat questions

Our Senses: The World's Greatest Smellers and the World's Worst Smell
For many animals, the sense of smell is crucial for survival. That is how sharks are able to detect a tiny drop of blood more than a mile away. Looking at a snake's rather minimal nose, you might be surprised to learn that snakes have excellent smelling abilities. But snakes do not smell with their noses. They use their tongues. Some birds are outstanding smellers, too. An albatross, soaring above the ocean, swoops down to capture its prey not because it sees that prey but because it smells it.

Consider how we think about the sense of smell. Although someone with a particularly sensitive nose might find a job testing perfumes, in general we do not think of humans as being very strong in the competition for sense of smell. But we might consider entering a contest for creating the world's worst smells! Pamela Dalton, a psychologist who studies sensation, cooked up a concoction that might just take first prize. Dalton created an odor for the U.S. Department of Defense, which was, at the time, considering using odors as nonlethal weapons to fight terrorists. The odor, called “stench soup,” pulls together chemicals responsible for the most disgusting smells: “rotting corpses and human excrement” coupled with “a sweet, fruity overtone” (Zitner, 2002).

Like other animals, we use our senses to survive. But we differ from animals in that we also use our noses, tongues, eyes, ears, and skin for many other purposes. The best and the worst aspects of the world around us compete for the title of our favorite (or most detested) smell, flavor, artwork, or song. And, of course, our senses also determine which we prefer—a back rub or a foot rub!