3.1-3.2: Introduction to Sensation & Perception

Sensory Deprivation

Also known as perceptual isolation, suggests that vision is at least partly on acquired taste.

Perceptual Adaptation

The visual ability to adjust to an artificially displaced visual field, e.g prism glasses.

Ponzo Illusion

Describes the instance when we use background objects to detect an object's distance.

Relative Size

If two objects are similar size, we perceive one that casts a smaller retinal image as farther away.

Subliminal Threshold Messaging

When stimuli are below ones absolute threshold for conscious awareness.

Depth Perception

The ability to perceive how close an object is to us at any given time.

Texture Gradient

Indistinct (fine) texture signals increasing distance.

Gestalt Grouping

Having discriminated figure from ground, our perception needs to organize figure into a more meaningful form using grouping rules.

Figure Ground

Your brain distinguishes between the objects it considers to be it considers to be in the foreground of an image (the figure, or focal point) and the background (the area on which the figures rest)

Absolute Threshold

Minimum stimulation needed to detect a particular stimulus 50% of the time.

Difference Threshold

Minimum difference between two stimuli required for detection 50% of the time, also called Just Noticeable Difference (JND)

Webers Law

The size of the JND is proportional to the intensity of the stimulus AKA.. if the stimulus intensity is high, the JND will be large (it will take a bigger chance to tell the difference), and vice versa

Signal Detection Theory

Simply put, it states that our thresholds are not absolute, they change

Similarity

they can be used to tie together elements that might not be right next to each other in a design, they can be grouped by color, shape, or size

Continuation

The law of continuity posits that the human eye will follow the smoothest path when viewing lines, regardless of how the lines were actually drawn, this can be a valuable when the goal is to guide a visitors eye in a certain direction

Proximity

refers to how close elements are to one another

Closure

The idea that your brain will fill in the missing parts of a design or image to create a whole

Symmetry/Order

States that your brain will perceive ambiguous shapes in as simple a manner as possible

Interposition

Objects that occlude (block) other objects tend to be perceived as closer

Linear perspective

Parallel lines like railroad tracks, appear to converge with distance

Convergence

When two eyes move inward (towards the nose) to see near objects, and outward (away from the nose) to see far away objects…object is perceived as closer the more eyes turn inward

Retinal Disparity

Images from the two eyes differ..the greater the difference between the two objects, the closer the object

Stroboscopic motion

our tendency to perceive motion in a rapid series of slightly varied still images in rapid succession

Phi Phenomenon

When lights flash at certain speed they tend to present illusions of motion

Moon Illusion

It appears larger and farther away when on the horizon (smaller and closer when up in the night sky)

Cultural Context

Context instilled by culture also alters perception

Context Effects

A given stimulus can evoke radically different perceptions, based on the immediate context of the stimulus

Perceptual Set

A mental predisposition to perceive one thing and not another... a tendency to perceive or notice some aspects of the available sensory data and ignore other.