Lecture 2 - Processing I

Question 1

Bottom-Up Processing

Answer 1

Stimulus…to attention… to perception…to thought process…to decision…to response
Start with stimulus
Build up representation
Ex: hearing a new song and animation for the first time (no expectation about it), seeing all the control of a plane for the first time

Bottom-up processing creates representations from stimuli without expectations

Question 2

Top-Down Processing

Answer 2

Expectation…to thought process….to Perception…to attention…to stimulus (how perceive stimulus)
Ex: optical illusion (expectation affects how we see the image)
Ex: McGurk Effect (perceive the sound ba differently when expect it to sound different (from the face of a person articulating a different sound fa)
● Start with expectation/context
● Helps interpret datastream

Top-down incorporates expectations into processing

Question 3

Brain recap

Answer 3

Lobes:
● Frontal (at the front) - Reasoning,
Planning, (speech),
movement, emotions
● Parietal (at the top back)- Movement,
orientation, Recognition
● Occipital (at the back, furthest from eyes)- Visual
● Temporal (at the bottom)- Auditory,
memory, speech

If eyes are at the front on the right (West):
-Dorsal is North (top)
-Ventral is South (bottom)
-Rostral is West (toward the face)
-Caudal is East (toward the tail)

-Anterior = front
-Posterior = back

See other parts (visual system)

Question 4

Evidence for bottom-up processing in brain

Answer 4

Lesion studies on monkeys
Dorsal pathway (up)= where pathway, parietal lobe
Ventral pathway (down) = what pathway, temporal lobe

Question 5

Gestalt Theory

Answer 5

Principles:
-Similarity: similar items grouped together
-Proximity: close items grouped together
-Closure: attempt to group stimuli
-Pragnanz: reduce to simple form
-Continuity: follow curves
(see images)

Gestalt criticism:
-too theoretical
-not great for complex scenes
-no priority

Gestalt theory suggests top-down biases for processing

Experimental Gestalt
-quantitative studies on lottts of people
Ex of test: Kubovy, Wagemans, 1995,
Grouping by Proximity and
Multistability in Dot Lattices:
a Quantitative Gestalt Theory
-Established a predictive model

Question 6

Developmental Psych

Answer 6

See Vernon cognitive roadmap, about grouping and object processing
P.21, PDF 33

Question 7

Miller’s Magic Number 7 (1956)

Answer 7

Remember 7+/-2 items at a time
Suggests serial processing (one after the other, one/few signals at a time)
Other strategies to help: making a story, chunking
Stimulus… senses… short-term store…. Filter… bottleneck… further processing

Question 8

Parallel/Serial Processing

Answer 8

Ex: monkey lesions, two cortical visual systems = serial
Ex: robot brains =serial processing
Neural networks can do amazing things with massively parallel processing

Detour – ANNs
Input… Output

Parallel NNs