Perception

Perception The process of organizing and interpreting incoming sensory information.

Gastalt Psychology The German psychologist of the 19th century believed that the whole is greater than the sum of its parts. -We group information to create a whole.

Grouping The perceptual tendency to organize stimuli into understandable units. -Similarity: Place items that look similar in the same group -Proximity: If objects are close together -Closure: Our brains tendency to look for the whole, not the parts, drives us to fill any gaps in a perceptual field. -Continuity: Once an object appears to move in a particular direction, your brain assumes that the movement continues unchanged.

Figure-Ground The organization of the visual field into objects (figures) that stand out from their surrounding (ground). -Figures: In most photographs and visual scenes, you can easily pick out the figure. Its what draws your attention. -Ground: consists of the surrounding aspects that we commonly call the background.

Depth perception: The ability to see in three dimensions and to judge distance. Binocular cues: Depth cues that require the use of both eyes. Monocular cues: Depth cues that require the use of only one eye.

Visual Cliff A laboratory device for testing depth perception in infants and young animals. https://www.youtube.com/watch?v=3WvtEFJGp-8

Retinal Disparity A binocular depth cue resulting from slightly different images produced by the retina of the left eye and the retina of the right eye.

Convergence A binocular depth cue related to the tension in the eye muscles when the eyes track inward to focus on objects close to the viewer.

Monocular Depth Cues Part of depth-perception is the ability to perceive the distance of an object. There are a variety of things that we use to judge how far away an object is. Some of these cues can be processed by just one eye, which is why they are referred to as monocular cues.

Monocular Depth Cues Relative Size: If two objects are roughly the same size, the object that looks the largest will be judged as being the closest to the observer. Texture Gradient: When you are looking at an object that extends into the distance, such as a grassy field, the texture becomes less and less apparent the farther it goes into the distance. Motion Parallax/ Relative Motion: As you are moving, objects that are closer seem to zoom by faster than do objects in the distance. When you are riding in a car for example, the nearby telephone poles rush by much faster than the trees in the distance.

Monocular Depth Cues Aerial Perspective: Objects that are farther away seem to be blurred or slightly hazy due to atmosphere. Linear Perspective: Parallel lines appear to meet as they travel into the distance. For example, the outer edges of a road seem to grow closer and closer until they appear to meet. The closer together the two lines are, the greater the distance will seem. Overlap (or Interposition): When one object overlaps another, the object that is partially obscured is perceived as being farther away.

Perceptual Constancy Perceiving the size, shape, and lightness of an object as unchanging even as the image of the object on the retina of the eye changes.

Size Constancy We expect size to remain constant. Our knowledge of the world leads us to conclude that when the apparent size of an object changes the actual size is not changing at all. What’ changing is the distance.

Shape constancy Assures us that an object’s shape has not changed even though the angle of view indicates it may have done so.

Lightness Constancy Gives us the ability to see an object as having constant level of lightness no matter how the lighting conditions change.

What do you see? It’s a beautiful day

What do you see? I love to count

What do you see? I love music 

Perceptual Set A mental predisposition to perceive something one way and not another. -Subliminal messages -schemas: concepts or mental frameworks that help organize and interpret information about the world. https://www.youtube.com/watch?v=n46umYA_4dM

Which line is longer? The Muller-Lyer Illusion

The Ames Room https://www.youtube.com/watch?v=IuY4h3Xh7S8

Gastalt Principle of closure

Illusions based on light

Fun Optical Illusions

Fun Optical Illusions

Fun Optical Illusions