Constructing the Visual WorldBottom Up & Top Down ProcessingForm perceptionDepth and distance perceptionVisual constancies: When seeing is believingVisual illusions: When seeing is misleading

What do you see??

Group AYou 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.

Group BYou 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 sword?A mans hat?A beach ball?A fish?

Top Down processing You go beyond the sensory information to try to make meaning out of ambiguity in your worldWhat you expect (your experiences and your perceptual set) drives this processBottom Up processingDigesting raw sensory information to make sense of something. Our feelings of pain combine both top down & bottom up processing. (tickling)

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

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

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

Form Perception GestaltGestalt principles describe the brains organization of sensory building blocks into meaningful units and patterns.

ProximityProximity 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

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

ClosureClosure 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.

ContinuationContinuation 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 VideoHow does the advertising world use Gestalt Principles?

Gestalt Principles Gone AwryObjects 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 PrinciplesProximitySeeing 3 pair of lines in A.SimilaritySeeing columns of orange and red dots in B.ContinuitySeeing lines that connect 1 to 2 and 3 to 4 in C.ClosureSeeing a horse in D.

Depth and Distance PerceptionBinocular 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.

Relax your eyes and try and focus behind the computer screen. (Convergence)

Retinal Disparity floating finger sausageHold your index fingers about 5 inches in front of your eyes, with their tips a half-inch apart. Now look beyond them and note the weird result. Move your fingers out farther and the retinal disparity- and the finger sausage- will shrink.Because our eyes receive different information about an object, their retinal disparity provides a binocular cue of an objects relative distance.

Depth and Distance PerceptionMonocular 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

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

Perceptual ConstanciesThe accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce.Shape constancyLocation constancySize constancyBrightness constancyColor constancy

Shape ConstancyEven though these images cast shadows of different shapes, we still see the quarter as round

Color ConstancyColor 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 IllusionsIllusions 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 IllusionLinear perspective provides contextSide lines seem to convergeTop line seems farther awayBut the retinal images of the red lines are equal!

Fooling the EyeThe cats in (a) are the same sizeThe diagonal lines in (b) are parallelYou can create a floating fingertip frankfurter by holding hands as shown, 5-10 in front of face.

Sensation & Perception*1999 Prentice Hall *Sensation & Perception*1999 Prentice Hall *Sensation & Perception*1999 Prentice Hall *Figure 3.23 from:Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.

Sensation & Perception*1999 Prentice Hall *Sensation & Perception*1999 Prentice Hall *Sensation & Perception*1999 Prentice Hall *Figure 3.24 from:Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.

Sensation & Perception*1999 Prentice Hall *Sensation & Perception*1999 Prentice Hall *Figure 3.25 from:Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.

Sensation & Perception*1999 Prentice Hall *Figure 5.07 fromWade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

Sensation & Perception*1999 Prentice Hall *Figure 3.3Davis 2 from:Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.

Sensation & Perception*1999 Prentice Hall *