Download
1 / 97
970 likes | 1.17k Vues
Sensation. Basic Concepts Characteristics of Sensory Systems The Visual System. Sensation. The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. (from text)
E N D
Sensation • Basic Concepts • Characteristics of Sensory Systems • The Visual System
Sensation • The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. (from text) • In other words…The process of converting physical stimuli (light, sound, heat, pressure, etc…) into the language of the brain (action potentials & neurotransmitter release). • Also known as “transduction” • Strongly associated with bottom-up processing: analysis strongly shaped by sensory receptors.
Important Thresholds • Absolute Threshold: The smallest possible amount of a stimulus that can be detected half (50%) of the time. • Difference Threshold: The smallest possible difference between two stimuli that can be detected half (50%) of the time.
Some Questions to Consider. • Would you notice a change of $10,000 in your bank account? • Would everyone notice a change of $10,000 in their bank accounts?
Weber’s Law • The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant minimum amount).
Two Theories of Color Vision • Trichromatic Theory • blue, green, & red sensors • Opponent Process Theory • Blue-yellow, red-green, & black-white sensors
Some Unusual Quotes • “N is sort of… rubbery… smooth, L is sort of the consistency of watery paint… Letters also have vague personalities, but not as strongly as numerals do.” • “The letter A is blue, B is red, C is a kind of light gray, D is orange…” • “I hear a note by one of the fellows in the band and it’s one color. I hear the same note played by someone else and it’s a different color. When I hear sustained musical tones, I see just about the same colors that you do, but I see them in textures.” • “Basically, I taste words.”
Synesthesia • The perceptual experience of one sense that is evoked by another sense. • For the typical person: A B C D E • For someone with synesthesia: ABCDE
Perception • Review • Important Points about Perception • Object Perception • Depth & Distance Perception • Illusions
I. Review • Sensation: The process of converting physical stimuli into the language of the brain. • Example: converting photons of light into nerve impulses • Perception: The process of integrating, organizing, and interpreting sensory information. • Example: recognizing the pattern of light that corresponds to the face of a friend
Bottom-Up versus Top-Down • Bottom-Up Processing: Information processing that is strongly shaped by adding up the inputs of sensory receptors. • Top-Down Processing: Information processing that is strongly shaped by higher level mental processes (such as expectations or beliefs).
II. Important Points about Perception • Perceptual systems often misperceive the world • Perceptions are strongly influenced by context • Perceptions are strongly influenced by beliefs and expectations
Gestalt Laws of Perceptual Grouping • We perceive as belonging together objects that.. • are close to each other (proximity). • are similar to each other (similarity). • are physically touching each other (connectedness). • form continuous lines, curves, or patterns (continuity/good continuation) • We also tend to perceive objects as more complete than they really are (closure).
Depth Cues • Monocular depth cues only require one eye • Binocular depth cues require two eyes
