Week 3

Color, Sensation, and Perception

What is Absolute Threshold?

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

What is Signal Detection Theory?

A model for predicting how and when a person will detect a weak stimulus, partly based on context.

What is Difference Threshold

The smallest amount by which two sensory stimuli can differ in order for an individual to perceive them as different.

Weber’s Law

We perceive differences on a logarithmic rather than linear scale. It’s not the amount of change but rather the percent of change that matters.

Transduction

The process through which something changes in a specific way. (Form shape, place, etc..)

Chromostereopsis

Pure colors at the same distance from the eye appear at different distances

How is Hue determined?

By length and frequency of the light waves

How is brightness determined?

By amplitude/amount of energy in a given light wave

How is saturation determined?

By light complexity

What does the retina contain?

Receptor cells, rods and cones

What do cones cover?

The fovea

What do rods cover?

Periphery (surrounds the fovea)

What makes the optic nerve?

Bipolar cells that are connected to ganglion cells

Edge detection

how we detect different objects, created by difference in color or brightness

Feature detectors

response to certain features to make out objects

Parallel Processing

ability to process and analyze many aspects of the situation at once

Depth perception

Allows us to estimate distances between objects and ourselves

What are monocular cues?

Depth perception cues that does not require both eyes

What is included in monocular cues?

Occlusion, relative size, relative height, texture gradient, familiar size, linear perspective, aerial perspective, and relative brightness

Occlusion

an object that blocks the view of another object must be in front of it.

Relative size

Smaller objects are farther away

Relative height

Objects that appear higher in our visual field are farther away than objects that are lower

Texture gradient

As a texture gets further away it forms smaller visual angles or picture on the retina and is less noticeable

Familiar size

Knowledge of the normal size of certain objects can provide cues to depth

Linear perspective

Parallel lines seem to converge as they move into the distance

Aerial perspective

Objects that are farther away also appear to be hazier and bluer

Relative brightness

Brighter images are closer and more shaded images are farther away

Proximity

The closer figures are to each other, the more we tend to group them together perceptually

Good Continuation

A preference for organizing form in a way where contours continue smoothly along their original course

Closure

Filling in information to complete perceptions

Pareidolia

The tendency to organize incomplete or random images into meaningful images

Nativism

Bottom-up processing; perception that involves innate mechanisms forged by evolution and that no learning is required.

Empricism

Top-down processing; hypothesis based on our prior knowledge

Shape constancy

ability to perceive the shape of a rigid object as constant despite differences in the viewing angle.

Affordances

Meanings in an environment; the potential actions individuals perceive when interacting with objects in their environment.

what order do we see in?

optic nerve → thalamus → visual cortex

What is color theory?

How colors work together

What is Hue?

Hue is the COLOR (red, green, purple, etc..)

What is Saturation?

Intensity (vibrant or dull)

What is Value?

Darkness or Brightness of the color

What are the Color Harmony formulas?

Monochromatic, Analogous, Complementary, Split complementary, triadic, and tetradic.