Drill 1.  The Amplitude of electromagnetic waves determines the ________of light Absolute Threshold Brightness Hue Difference Threshold Wavelength  2. Which theory best explains how we perceive low-pitched sounds? Place Theory Opponent – Process Theory Frequency Theory Young-Helmholtz Theory Gate-control Theory 

Unit 5: Sensation, Perception and States of Consciousness NHHS AP Psychology Unit 5: Sensation, Perception and States of Consciousness Essential Task 5-5:  Describe general principles of perception/ top down processing (organizing and integrating sensation) that promote stable awareness of the external world with specific attention to the Gestalt principles of figure/ground, closure, proximity, connectedness, similarity and the mono and binocular cues for depth perception). Logo Green is R=8 G=138 B=76 Blue is R= 0 G=110 B=184 Border Grey is R=74 G=69 B=64

Perceptual Constancies Sensation Vision The Eye Theories Hearing The Ear Other Senses Smell Taste Pain Gestalt Principles Perceptual Constancies Perception Basic Principles Visual Illusions Depth Perception We are here

Constructing the Visual World Bottom Up & Top Down Processing Form perception Depth and distance perception Visual constancies: When seeing is believing Visual illusions: When seeing is misleading

Digesting raw sensory information to make sense of something. Why did we see different things? Bottom Up processing Digesting raw sensory information to make sense of something.   Our feelings of pain combine both top down & bottom up processing.  (tickling)  Top Down processing  You go beyond the sensory information to try to make meaning out of ambiguity in your world What you expect (your experiences and your perceptual set) drives this process 

What do you see??

Group A You are going to look briefly at a picture and then answer some questions about it. The picture is a rough sketch of a poster for a costume ball (formal dance). Do not dwell on the picture. Look at it only long enough to “take it all in” once. After this, you will answer YES or NO to a series of questions. lkddjkfjkfdf

Group B You are going to look briefly at a picture and then answer some questions about it. The picture is a rough sketch of a poster for a trained seal act. Do not dwell on the picture. Look at it only long enough to “take it all in” once. After this, you will answer YES or NO to a series of questions.

Picture

In the picture was there . . A car? A man? A woman? A child? An animal? A whip? A cane? A fancy dress? A beach ball? A fish?

How old is the woman on the following slide? Without speaking, write your answer on a piece of paper.

How old is this person? Another look...

Perceptual Ambiguity Your brain tries to make sense of what you are looking at based on the region you are focusing on.

Gestalt- See the whole picture, not just the parts

Figure-Ground To recognize an object (figure) we must first perceive it as distinct from its surroundings. (ground)

Examples of figure-ground

Figure-ground examples

Form Perception – Gestalt Sensation & Perception * Form Perception – Gestalt Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns. Proximity Similarity Closure Continuation Figure 3.24 from: Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall. ©1999 Prentice Hall 20

explanation...

Proximity Proximity occurs when elements are placed close together. They tend to be perceived as a group. The fifteen figures above form a unified whole (the shape of a tree) because of their proximity. Reading

Similarity Similarity occurs when objects look similar to one another. People often perceive them as a group or pattern.

Similarity

Closure Closure occurs when an object is incomplete or a space is not completely enclosed. If enough of the shape is indicated, people perceive the whole by filling in the missing information. Although the panda is not complete, enough is present for the eye to complete the shape. When the viewer's perception completes a shape, closure occurs.

Continuation Continuation occurs when the eye is compelled to move through one object and continue to another object. Viewer's eye will naturally follow a line or curve. The smooth flowing crossbar of the "H" leads the eye directly to the maple leaf.

Proximity and Closure

Gestalt Principles Gone Awry Objects located within very little distance of one another. become related as a group, even if they are dissimilar in almost every way--in form, texture, value, or color. Sign is read from top to bottom because of the how the words are arranged in columns. If read as a column, the words do not make sense, but if read the correct way, the sign tells us something important.

Poorly placed dollar sign…

Gestalt Principles Proximity Similarity Continuity Closure Sensation & Perception * Gestalt Principles Proximity Seeing 3 pair of lines in A. Similarity Seeing columns of orange and red dots in B. Continuity Seeing lines that connect 1 to 2 and 3 to 4 in C. Closure Seeing a horse in D. Figure 3.25 from: Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall. ©1999 Prentice Hall 31

Depth and Distance Perception- vid clip Binocular Cues: Visual cues to depth or distance that require the use of both eyes. Convergence: Turning inward of the eyes, which occurs when they focus on a nearby object. Retinal Disparity: The slight difference in lateral separation between two objects as seen by the left eye and the right eye.

Depth Perception Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Even newborn animals show depth perception. OBJECTIVE 5| Explain the importance of depth perception, and discuss the contribution of visual cliff research to our understanding of this ability. Visual Cliff

Binocular Cues: Retinal Disparity Retinal disparity: Images from the two eyes differ. While focusing far away try touching your fingers about 5 inches directly in front of your eyes. You will see a “finger sausage” The amount of disparity (difference) between the two images can be used as a cue for distance Try holding up two fingers one in front of the other. Focus on the front one (you should now see two images of the back one). Now move the back one away from, then back towards you, while still focusing on the front one.

Binocular Cues: Convergence Convergence: Neuromuscular cues. When two eyes move inward (towards the nose) to see near objects and outward (away from the nose) to see faraway objects. OBJECTIVE 6| Describe two binocular cues for perceiving depth, and explain how they help the brain to compute distance.

Depth and Distance Perception Monocular Cues: Visual cues to depth or distance that can be used by one eye alone. Horizontal-vertical illusion (perceiving vertical dimensions as longer than horizontal

Monocular Cues Relative Size: If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away. OBJECTIVE 7| Explain how monocular cues differ from binocular cues, and describe several monocular cues for perceiving depth.

Monocular Cues Interposition: Objects that occlude (block) other objects tend to be perceived as closer.

Monocular Cues Relative Clarity: Because light from distant objects passes through more light than closer objects, we perceive hazy objects to be farther away than those objects that appear sharp and clear.

Monocular Cues Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance.

Monocular Cues Texture Gradient: Closer objects tend to have a courser texture than to far way objects

Monocular Cues Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction.

Monocular Cues Light and Shadow: Nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the ones that are shaded on top are seen as “sticking out toward us”

The Ames Room- vid clip A specially-built room that makes people seem to change size as they move around in it The room is not a rectangle, as viewers assume it is A single peephole prevents using binocular depth cues

Perceptual Constancies The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce. Shape constancy Location constancy Size constancy Brightness constancy Color constancy

Sensation & Perception * Shape Constancy Even though these images cast shadows of different shapes, we still see the quarter as round Figure 3.3Davis 2 from: Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall. ©1999 Prentice Hall 46

Color Constancy Color remains constant even when lighting and wavelengths shift. It demonstrates that our experience of color comes not only from the object, but everything around it as well.

Visual Illusions Illusions are valuable in understanding perception because they are systematic errors. Illusions provide hints about perceptual strategies. In the Muller-Lyer illusion (above) we tend to perceive the line on the right as slightly longer than the one on the left.

The Ponzo Illusion Linear perspective provides context Side lines seem to converge Top line seems farther away But the retinal images of the red lines are equal!

Perception of Movement Stroboscopic motion Created by a rapid series of still pictures Phi phenomenon Apparent motion created by lights flashing in sequence