PART 6: Sensation and Perception

16.1 Processing Sensation and Perception

Figure 6.1: FIGURE 16.1 What’s going on here? Our sensory and perceptual processes work together to help us sort out complex images, including the hidden couple in Sandro Del-Prete’s drawing, The Flowering of Love.

16-1 What are sensation and perception? What do we mean by bottom-up processing and top-down processing?

sensation the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

perception the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Heather Sellers’ curious mix of “perfect vision” and face blindness illustrates the distinction between sensation and perception. When she looks at a friend, her sensation is normal: Her sensory receptors detect the same information yours would, and her nervous system transmits that information to her brain. Her perception—the processes by which her brain organizes and interprets sensory input—is almost normal. Thus, she may recognize people from their hair, gait, voice, or particular physique, just not their face. Her experience is much like the struggle any person would have trying to recognize a specific penguin.

In our everyday experiences, sensation and perception blend into one continuous process.

bottom-up processing analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information.

top-down processing information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

Our bottom-up processing starts at the sensory receptors, which receive sensory input, and works up to higher levels of processing.
Our top-down processing creates meaning from this sensory input by drawing on our experience and expectations.

As our brain absorbs the information in FIGURE 16.1, bottom-up processing enables our sensory systems to detect the lines, angles, and colors that form the flower and leaves. Sensation is the world’s gateway to the brain. Using top-down processing we then interpret what our senses detect.