5.1 - How Do We Sense and Perceive the World Around Us?

Question 1

Sensation

Answer 1

detection of physical stimuli and the transmission of this info to the brain
- takes external stimuli and turns it into something understandable for the brain

Question 2

Perception

Answer 2

processing, organization and interpretation of sensory signals in the brain

Question 3

Bottom-up processing

Answer 3

Perception based on the physical features of a stimulus

Question 4

Top-down processing

Answer 4

Perception based on previous knowledge, expectations, and past experiences
(ex. we don’t see a blue apple shaped object as a real apple because we know they aren’t blue)

Question 5

Transduction

Answer 5

How sensory stimuli are converted into neural signals that the brain can interpret

Question 6

Sensory receptors

Answer 6

Specialized cells in the sense organs that receive stimulation and pass that info to the brain in the form of neural impulses

Question 7

What brain structure does most sensory info first go to?
And which sense doesn’t?

Answer 7

The Thalamus to the specific region of the cerebral cortex
- Except for smell which goes directly to the cortex

Question 8

Qualitative information about a stimulus

Answer 8

• most basic qualities of a stimulus (ex. salty tastes vs sweet) (the colour of a traffic light)

Question 9

Quantitative information about a stimulus

Answer 9

• degree or magnitude of those qualities (ex. how loud a honk is or how salty something tastes compared to something else) (how bright the traffic light is)

Question 10

Sensory pathways

Answer 10

sensory neurons that carry impulses from the receptors to the CNS

Question 11

Q: What is transduction?

Answer 11

the translation of physical stimuli received by sensory receptors into neural signals that the brain can interpret

Question 12

Sensory areas

Answer 12

Specific areas of the cerebral cortex designated for analyzing/organizing sensory info

Question 13

Absolute threshold

Answer 13

minimum intensity of stimulation that must occur before you experience a sensation
- is correctly guessed 50% of the time

Question 14

What did Fechner suggest about stimulis

Answer 14

Just Noticeable Difference (JND)
More commonly known as the difference threshold
- the smallest difference between 2 similar stimuli that can be distinguished 50% of the time

Question 15

What did Ernst Weber think about JND

Answer 15

• size of a JND depends on the intensity of the stimulus
  ex. in order for someone to notice a difference in volume of a choir, you would need to add a lot more than 1 singer to the group)

Question 16

What is a Weber fraction?

Answer 16

equation to determine the size of a JND c=1/10

Question 17

Signal Detection Theory (SDT)

Answer 17

theory of perception based on the idea that the detection of a stimulus requires a judgement and that it is not an all or nothing process

Question 18

Sensory adaptation

Answer 18

if a stimulus is presented constantly (ex a weird smell or the sound of a fan) there is a decrease in sensitivity to that stimulus (ex. you eventually get used to the weird smell or tune out the fan noise)

Question 19

Synesthesia

Answer 19

• people experience unusual combinations of sensations
• hearing what a food tastes like, seeing each letter as a different colour, etc.

Question 20

what is the process of transduction? (the order)

Answer 20

physical stimulus
sensory neurons
neural impulses
brain