Sensation and Perception

Question 1

Describe what a sensation is

Answer 1

The process by which detect and process sensory stimuli. Processing our environment through sight, smell, touch, and taste.

Question 2

Describe what perception is

Answer 2

The process by which we interpret the sensations.

Question 3

Description: Sensory receptors convert physical energy with neural responses.

Answer 3

Transduction

Question 4

What is absolute threshold?

Answer 4

The lowest level of a stimulus that an organism can detect. Ex: light, sound, touch.
50% of the time

Question 5

Difference threshold?

Answer 5

Comparison. Making slight changes and being able to know the difference.

Question 6

Sensor adaptation?

Answer 6

We don’t respond to every sense. Example, not being able to smell something until you leave and come back.

Question 7

Definition: A psychological event from the movement of ai molecules caused by the vibration of an object.

Answer 7

Sound.

Question 8

How is loudness measured?

Answer 8

By amplitudes.

Question 9

How is pitch measured?

Answer 9

By frequency.

Question 10

What is timbre?

Answer 10

The complexity of a sound wave. Distinguishes it from others of the same frequency and amplitude.

Question 11

Pinna, eardrum.

Answer 11

Outer ear.

Question 12

Vibration of eardrum sets bones in motion.
-Hammer (malleus), anvil (incus), stirrup (stapes).

Transmit and amplify motion of eardrum (x22). Stirrup vibrates against oval window.
-Amplifies waves.

Answer 12

Middle ear.

Question 13

Creates fluid waves in the cochlea. Amplification needed as fluid offers more resistance.
Cochlea: coiled spiral, snail like structure. Fluid filled.

Length of cochlea is divided in two by the Basilar Membrane.
BM vibrates in response to fluid waves.
On the BM, hair cells (receptor cells) push against rectoral membrane and they bend.
An action potential is triggered.
Message transmitted through the auditory nerve to auditory cortex.

Answer 13

Inner ear.

Question 14

What are the 4 steps of vision?

Answer 14

1. Gather light into eye.
2. Light channeled to back of eye.
3. Transduction occurs.
4. Info goes to brain to be interpreted.

Question 15

What is the role of the cornea?

Answer 15

Curved, transparent protective tissue. Curve bends (refracts) light on to lense.

Question 16

Pupil?

Answer 16

Adjustable opening that controls amount of light being able to get into eye.

Question 17

Iris?

Answer 17

Ring of muscle around pupil. Contracts and controls size of pupil.

Question 18

Lens?

Answer 18

Clear, elastic structure. Reverses and inverts image to focus on retina. Lens changes shape depending on distance of the image. Thin= distant. Thick= near.

Question 19

Retina?

Answer 19

Performs sensory function of the eye. 126 million light sensitive receptor cells. Transduces light into neural activity.

Question 20

What is transduction?

Answer 20

It occurs in the RETINA. 
Fovea is a small area in the back of the retina where acuity is best. 
3 layers:  
Ganglion cell layer (front), 
Bipolar cell layer (middle), 
Photoreceptor layer (rods and cones) 

Rods and cones contain photo pigment chemicals. Light hitting the PP causes a chemical reaction. Results in release of NT’s. NT’s trigger BP layer to fire, which triggers the ganglion cells. Then to the optic nerve and visual cortex to the brain.

Question 21

Concentrated in fovea. Few in periphery. Function when light is bright. Can retrieve acuity and colour. 6 million of them.

Answer 21

Cones

Question 22

Concentrated in periphery. More sensitive to light (permit vision in low light). Lacks colour detection and acuity . 120million of them.

Answer 22

Rods

Question 23

What is perceptual organization?

Answer 23

Proximity (elements closed together tend to be perceived as a group) 
Similarity 
Closure 
Good continuation 
Symmetry 
Simplicity

Question 24

What is perceptual constancy?

Answer 24

When we view objects from different angles, distances, lighting conditions, etc. and we see them as maintaining the same size, shape, brightness, etc.

Size constancy: perceive image as same size even when retinal image is smaller. Assume it is farther away (recognizing is is farther away).

Question 25

What is depth perception?

Answer 25

The image on our retina is 2D but we translate it in a way that we perceive depth. Can tell how far away an object is.