Rules of Perceptual Organization: Similarity

Perhaps the most obvious through shape differences, the perceptual organization rule of similarity defines how the brain will automatically group similar objects together; whether the common thread between them be color, shape, size, etc. In this example, the brain groups the objects into three groups: the black squares with white, soft crowns; the white squares with the black soft crowns, and the single white square with the black pointy crown.

In this example, the single yellow man stands out from the other men solely because of his color. The other black figures blend in because of their identicalness, while the yellow man, although his shape is exactly like the others, is impossible to ignore.  

Rules of Perceptual Organization: Continuity

The brain prefers perceiving patterns that are continuous and smooth as opposed to choppy, broken up objects. The ability of an image to allow our eyes to "flow" easily through lines and shapes is a strong example of the continuity rule of perceptual organization. In this example, the first two shapes appear as x's, each with lines bisecting one another. However, in the third image, the dark blue line appears continuous through the northern and western ends, while the light blue line is connected throughout the southern and eastern ends. The brain identifies and associates the colors along with the shapes and movement of the "lines" in the x.

 Additionally, this image of two paths diverged in a (green) wood offers the continuity of the gray path, while the brown path seems to be the branch that is diverging away from the main road. Because the color arises from the majority of bottom of the photo and extends deeper into the page, it is perceived as the "most continuous."

Perceptual Organization: Closure

One of the most crucial components of perception is being able to group and organize stimuli into similar patterns based on colors, shapes, contrast and movement. One of the ways the brain can do this is through the organizational rule of closure, which allows figures to be perceived from lines and shapes that may not completely be present -- basically, the brain will fill in the gaps. In this example of a panda bear, the back and the top and side of the bear's head are missing, but understanding that the image is portraying this animal is simple for the brain. 

In another, less obvious example, the brain perceives a white triangle, overlapping three black circles and another white triangle with a black outline. However, the "lines" of the white triangle on top are not really present, but are only created by the absence of the black lines and pieces of the circles that are apparently missing. The brain fills in these gaps and perceives the entirely white triangle.

Perceptual Constancies: Shape Constancy

Even though the shape of objects is always constant, the change in angle when viewing an object can make it seem like the object has a different shape; however, size constancy allows humans to perceive objects as having a constant shape even if there are changes in the angle of perspective.

For example, in the first picture, the painting has a rectangular shape, while in the second, picture, the angle that the painting is viewed from causes it to have a more trapezoidal shape. Even though the painting seems the shape of a trapezoid, humans still see it as rectangle due to shape constancy.     

Perceptual Constancies: Brightness Constancy

Brightness constancy (also known as lightness constancy) allows humans to identify an object as having a constant color even if the light in the environment changes. That is, no matter the level of the light, we can still tell the color of an object.

For example, due to brightness constancy, humans can tell that snow is white even in the darkest of places. Also, they can tell that coal is black even under bright sunlight. Even though the illumination in both environments is very different, humans are able to differentiate the color of the objects, and that color is constant no matter how much sunlight there is. 

Perceptual Constancies: Size Constancy

At different distances, it seems like objects have different sizes; however, size constancy allows humans to perceive objects as having a constant size no matter what the distance. Size constancy also shows the relationship between distance and size. For instance, when humans see an object and know its size, it gives humans an indication of how far the object is.

For example, in the picture below, due to size constancy, we know that the shoe is very close to the camera, and the humans are very far away from the camera because humans are definitely bigger than shoes.

Motion Perception

We experience motion perception in different ways. Sensations are disassembled into information bits that the brain then reassembles into its own functional model of the external world. The brain computes motion based partially on its assumption that shrinking objects are retreating and enlarging objects are approaching. Motion perception is also seen through a continuous movement in a rapid series of slightly varying images. Lastly, through the phi phenomenon, two or more lights blink on and off in quick succession to cause a perception of a single light moving back and forth between them.

For example, the brief video clip below will provide an example of motion perception in terms of a series of varying images put together to provide a perception of motion. Because the illustrator has put together several images of the progression of his drawing of a skull in the video, we perceive it as an actual video of someone actively drawing the skull.

Monocular Cue: Interposition

Interposition is another type of monocular cue. This is described as if one object partially blocks the view of another, that object is perceived as closer.

We face this monocular cue every day of our lives when we are either inside of a building or outside.
For example, in the picture below of a man standing before several buildings downtown, we experience interposition right away. Instead of seeing a giant man towering over the hundred-feet high buildings, this monocular cue tells us that because this man partially blocks the objects ahead of him, the man is in fact closer to us.

Monocular Cue: Relative Size

Monocular cues are depth cues available to either eye alone.
One of many monocular cues is relative size. If two objects are assumed to be similar in size, the one that casts the smaller retinal image is perceived as farther away.

For example, in the picture below, we perceive the large black ball with an 8 as closer to us than the smaller orange ball which is farther away. However, we know that both balls are of the same size, yet since the ball that is farther away takes up less of our field of view, we can perceive the distance between both balls.

Binocular Cue

One instance of a binocular cue is convergence. This says that as an object gets closer to our face, our eyes must move toward each other to keep focused on the object.

Everyone can relate to this binocular cue as we have all held a pencil in front of our faces and moved the object closer and closer to our faces until we become cross-eyed. This occurs because in order to remain focused on an object which is closer to our faces, our eyes must move toward each other to keep it in focus. This is most likely the most infamous instance of convergence:

Rules of Perceptual Organization: Figure-Ground Perception

When we first look at visual perception, we must make the figure-ground relationship. We must determine which part of the figure is the ground and which is the background.

For example, in the following image, one can perceive either the statues as being the ground and the wall as the background, or, one can perceive the space between the pottery (the men) as being the ground and the vases as being the background. This relationship allows the ground and background to switch intermittently:

 

As another example, this bookshelf can either be perceived as a bookshelf with various objects located on it or an arrangement of objects to form the shape and appearance of a skull:

Rules of Perceptual Organization: Proximity

In psychology, proximity refers to the fact that when objects are close together, we are more likely to perceive them as belonging to the same group.

For example, in the following picture, we perceive the sheep as belonging to three groups since the front three sheep are clumped together, the middle two sheep are clumped together, and the two sheep in the back are grouped together. The sheep's proximity to one another makes us perceive three separate groups:

In addition, in the proceeding picture, we perceive there to be two groups of children for the same reason: