Monocular Cues for Depth Perception:

The red circle is further away because it's behind the triangles.
 
 

Relative Size

The green circle is closer because it's bigger.
 

Perception: How we select, organize, and interpret information from our senses.
Distal Stimulus: A physical object in the world.
Proximal Stimulus: The information in our sense organs - comes from sensation.
Percept: How we finally mentally experience the distal stimulus.

We can't really experience physical objects in the world.
We only experience percepts that we put together ourselves.

Perception involves tuning proximal stimuli into percepts that are like the distal stimulus.

Perception has 3 parts:
1.  Noticing: what information do we pay attention to in the environment?
2.  Organization: how we put together the information from our senses.
3.  Interpretation: the judgments we make once a percept is formed.

What affects what we notice?

1. Goals (if you're hungry you'll notice food)
2. Experiences (if you've been bitten by a dog you'll notice dogs' teeth).

Steps in Organization:

1. Determining figure and ground
2. Grouping stimuli into meaningful shapes, according to closure, proximity, similarity, and common fate.
3. Making the figure 3-dimensional

Interpretation

One set of important issues in interpretation involves constancies - objects retain their size, shape, and color, even when the image that appears on our retina changes as the object moves around.