Size Constancy

When we see the same object up close and far away we perceive that the object that's farther away is smaller even though in reality they're the same size. This is called size constancy which  is when we perceive objects as having a constant size even when our distance from them varies. One example is in the picture below. The shoe up front seems larger than the one further back but based on our knowledge we already know that both shoes are the same size, our eyes are just perceiving them as different.

Brightness Constancy

Also called Lightness Constancy its when we perceive an object as having a constant lightness even while its illumination varies. This depends on the relative luminescence or the amount of light an object reflects relative to its surroundings. One example would be a piece of paper under a bright light verses the same paper under a dimmer light. Our eyes perceive the paper as being lighter with the bright light than in the dimmer light but based on our knowledge we know the white paper is always white no matter how dark or light it is.

Shape Constancy

When an objects shape changes depending on the angle we view it at even though the actual size cannot change is called shape constancy. Its when we perceive the form of familiar objects as constant even while out retinal images of them change. For example the CD below looks thin in the top left picture, but then in the one next to that the CD looks wider. Finally in the bottom picture the full surface o the CD is shown and it seems to have a different shape compared to the other two when really it doesn't; its just the angle of the camera that distorts our vision of seeing the whole CD.

One of the binocular cues is convergence.  This is a neuromuscular cue which causes one's eyes to turn inward when focusing on a closer object.  This allows the brain to know which object to focus on.  In the first picture, the eyes turn inward more because the pencil being looked at is held at a close distance.  In the second picture, the eyes are farther apart as they focus on the pencil, which is at an arm's length.

The fifth rule of perception  is figure-ground perception.  This is when one distinguishes a certain object (the figure) from other objects (the ground or background).  This rule can be seen in the pictures below.  In the first picture, the book page cannot be read because the focus is on the ground (the stool) instead of on the figure (the book page). In the second picture, the book page is clear, and the stool it sits on is blurry.  This is because the focus is on the figure and not on the ground, as opposed to the first picture, where the opposite is true.

The fourth rule of perceptual organization is proximity. This is when our mind groups nearby figures together.  For example, in the picture below, one would likely see one group of two purple stripes and two groups of three purple stripes instead of eight individual purple stripes.

Real-Life Motion Perception

Here's an example of our minds perceiving motion when there actually isn't any. The images are individual images drawn on different pieces of paper, but when shown rapidly, they give the illusion of motion (in this case, the video of a very catchy K-pop song).

*Taken from YouTube*

Motion Perception

Our brains perceive motion based on assumption.

Stroboscopic Movement: Continuous movement in rapid series of images (movies/animation)

Phi Phenomenon: Lights blinking on and off; appear to be a single light in motion

Real-Life Monocular Cues

Relative Size

The man appears smaller than the girl because he is further away, even though he is taller.

Linear Perspective

The wood grain pattern is more faint as the floor goes on.

Monocular Cues

Monocular cues are available to each eye separately.

Relative Size: Assuming that two objects are the same size, the object with the smaller image looks farther away.

Interposition: When one object partly obscures another, it is perceived as closer.

Relative Clarity: Fuzzy/hazy objects look farther away, clear objects look closer.

Texture Gradient: Change from coarse to fine texture increases distance.

Relative Height: Objects higher in field of vision appear farther away.

Relative Motion: When moving, still objects appear to be moving.

Linear Perspective: Parallel lines seem to come together with distance.

Light and Shadow: Close objects reflect more light.

Real life example of similarity

In this picture of a kitchen cabinet, we group the cups into those who are similar to each other rather than seeing it as rows of cups.

Real life example of continuity

In this windowpane, we see it as being made up of two vertical lines and one horizontal line rather than six squares, because seeing it as lines makes it made up of smooth and continuous lines.

Real life example of closure

In the picture of this heating vent, in the middle we see an incomplete rectangle, and, instead of seeing it as this different shape, we see it as being overlapped by the adjoining rectangle so it is complete.

Similarity

A third rule of perceptual organization is similarity. This means that we group objects in groups where they are similar to each other. Such as in the picture below, we see a cross of squares and four squares of circles rather than rows or columns of circles and squares.

Continuity

A second rule of perceptual organization is continuity.  This means that we perceive patterns as smooth and continuous rather than as discontinuous shapes, such as the picture below. When viewing the picture of dots below, we view it as two lines shown in the upper left picture rather than the lines shown in the upper middle picture, because the lines in the upper left picture are smooth and continuous.

Closure

One rule of perceptual organization is closure. This means we see an object as a whole even when it is just made of parts.  This rule, originating from the gestalt psychologists, is depicted here, as we see a complete rectangle even though it is just disconnected lines.