Modules 18-19

Modules 18-19

Visual Organization

Open Ended

What are the two key theories of color vision? Are they contradictory or complimentary? Explain.

Feature Detection

• thought brain was like a movie screen at one time - eye just protecting images

• David Hubel and Torsten Wiesel (1979) - visual processing deconstructs visual images and reassembles them

Feature Detection

• Hubel and Wiesel receive Nobel prize for research

• Feature Detectors - nerve cells in the occipital lobe's visual cortex that respond to a scene's edges, lines, angles, and movements

Feature Detectors

• Experiment with cat showed that some neurons fired actively with one angle and some another

• Feature detectors pass specific information to other cortical areas where teams of cells (supercell clusters) respond to more complex patterns.

Feature Detectors

• experiment when applied to temporal lobe - fusiform face area

• you will spontaneously see faces!

• ability to see faces can be disrupted by magnetic pulses

• brain's face perception occurs seperately from object perception

Poll

Does your brain process recognizing a face differently than a flower?

• Yes

• No

Parallel Processing

• processing many aspects of a problem simultaneously - brain's natural mode of information processing for many functions, including vision

• when viewing a visual scene, brain divides it into subdimensions (motion, form, depth, color and works on each aspect simultaneously

Parallel Processing

• then we construct our perceptions by integrating (binding) the separate but parallel work of the different visual teams

• ex. recognize a face - brain integrates information projected by your retinas to several visual cortex areas and compares it with stored information - grandmother cells

Parallel Processing

• scientists have debated whether or not grandmother cells are one supercell or a network

• some supercells are called grandmother cells - respond selectively to 1 or 2 faces out of 100

• whole face recognition requires tremendous brain power - 30% of cortex - 10x more than use of brain for hearing

Open Ended

This or that: Choose one - Why do you think supercells for facial recognition are called grandmother cells?

Do you think wearing masks increases or decreases facial recognition?

Open Ended

What was blindsight or give an example of it?

Blindsight

• when a section of the neural workstation for a visual subtask is damaged, weird results can happen - blindsight

• report seeing nothing

Visual Perception pg. 184

Open Ended

What is the rapid sequence of events that occur when you see and recognize a face?

Poll

Do you enjoy organizing or watching organizational shows?

• Yes

• No

How would you organize this room?

Respond in chat or out loud

Perceptual Organization

• gestalt psychology - an organized whole

• emphasizes our tendency to integrate pieces of information into meaningful wholes

• gestalt - form or whole

• In perception - whole may exceed the sum of its parts

• Our brain does more than register information about the world

• We filter incoming information and construct perceptions