Lecture 4

Question 1

What are the types of processing?

Answer 1

Bottom-up and Top-down

Question 2

What is bottom-up processing?

Answer 2

Bottom-up processing: starts at sensory receptors and works up to higher levels of processing

Question 3

What is top-down processing?

Answer 3

Top-down processing: constructs perceptions from sensory input by drawing on our experiences and expectations

Question 4

What is Sensation?

Answer 4

• Sensation (the biological “hardware”)
• The receipt of external (environmental) stimuli
• World full of stimuli: Light waves, sound waves, physical objects, chemicals…
• Need systems that are sensitive to these stimul

Question 5

Sensation: How do we detect stimuli?

Answer 5

We have structures that change in response to stimuli
Example: anemometer – responds to wind, not light
We have cells that change in response to light, but to nothing else
So, some cells change in response to stimuli
How does that translate into a recognizable image, voice, taste, feeling, or smell?

Question 6

What is Transduction?

Answer 6

Transduction
Conversion of energy from one form into electrical impulses in nervous system
Example: Telegraph converts pressure into electricity
Receptor cells do the same!

Question 7

What is Perception

Answer 7

Now we have a neural signal…
Perception (the “mental software”): Creating meaning from transduced sensory information
Job of specialized brain areas
Look for patterns, compare to memory, integrates information across senses

Question 8

Perceptual Set

Answer 8

Ambiguous stimulus: Same sensation, multiple perceptions
Context activates a perceptual set
Perceptual set:
Assumptions, based on expectations, that bias perception to see perceive one thing and not another.
What we expect to perceive influences how we actually perceive things.
Makes us notice some aspects of the available sensory data and ignore others

Question 9

Perceptual Set : What is Ambiguous stimulus?

Answer 9

Ambiguous stimulus: Same sensation, multiple perceptions

Context activates a perceptual set

Question 10

Perceptual set:

Answer 10

Perceptual set:
Assumptions, based on expectations, that bias perception to see perceive one thing and not another.
What we expect to perceive influences how we actually perceive things.
Makes us notice some aspects of the available sensory data and ignore others

Question 11

Why do we care about perceptual set?

Answer 11

Because marketers influence our perceptual set to make us buy things.
Study: California wine versus North Dakota wine
Study: Brownies
Study: Menu descriptions
Take home message: Perceptual set influences how things taste

Question 12

What is Sensory Adaptation?

Answer 12

Diminished sensitivity as a consequence of constant stimulation. E.x. High heels hurt your feet, but they are fashionable so you will eventually think they don’t hurt anymore.

Question 13

Take home message of Sensation, Perception, Transduction…

Answer 13

What we perceive is NOT a perfect representation of the world around us.
It’s influenced by the limitations of our sense organs and our expectations.

Question 14

The Visual System – Color Vision

Answer 14

-Colour Vision
-Young-Helmholtz trichromatic theory
-Three “kinds” of cones (retina):
Red
Green
Blue

Question 15

The Visual System – Color-Blindness

Answer 15

• Color-blindness
• Monochromatic
• Total color blind
• Black-and-white
• Often caused by damaged / missing cones

Question 16

The Visual System – Color Vision

Answer 16

-Hering’s opponent–process theory
-Three sets of processes in the retina:
Red / green
Yellow / blue
White / black
-Phenomenon: Adapt to one color, then remove it, it’s opposite activates relatively more

Question 17

The Visual System – Color Vision: What is Phenomenon?

Answer 17

Phenomenon: Adapt to one color, then remove it, it’s opposite activates relatively more

Question 18

The Visual System – Color Vision

Answer 18

• Trichromatic vs. opponent-process theories
• Which one is right?
• Both!
• Trichromatic process happens in cones
• Opponent-process happens later on in the brain

Question 19

The Visual System – Organization

Answer 19

Gestalt: The whole is greater than the sum of its parts

A whole that is organized, meaningful

Question 20

The Visual System - Grouping

Answer 20

Proximity: We group things together that are near each other

Continuity: We group together objects whose contours form a continuous straight or curved line

Closure: We live in a world of whole objects, and therefore fill in gaps to complete figures

Question 21

The Visual System - Grouping: What is Proximity?

Answer 21

Proximity: We group things together that are near each other

Question 22

The Visual System - Grouping: What is Continuity?

Answer 22

Continuity: We group together objects whose contours form a continuous straight or curved line

Question 23

The Visual System - Grouping: What is Closure?

Answer 23

Closure: We live in a world of whole objects, and therefore fill in gaps to complete figures

Question 24

The Visual System - Motion

Answer 24

• Apparent motion
• Shape and color information play a role in perceiving motion
• Phi phenomenon
• We “fill in the blanks” and infer motion from location change

Question 25

Subliminal Messages

Answer 25

Means below one’s conscious awareness
You sense it (the stimulus is processed by your sensory receptors)
But you perceive it (organize and interpreted it) automatically – without being aware that you are doing so

Question 26

Can people absorb subliminal messages?

Answer 26

Yes!
Subliminal messages can’t control our behaviour
But in an unstructured situation, they can influence our behaviour somewhat