Psych : Sensation And Perception

Front 1

Sensation

Back 1

What you see. You may not know what you’re looking at.

Front 2

Sensory transduction

Back 2

The process of turning physical input (such as light) into the electrochemical language of your nervous system.

Front 3

Perception

Back 3

The process of assignment meaning to that stimulation

Front 4

Visual transduction

Back 4

“Visible” light forms just one part of the spectrum of electro-magnetic radiation

Front 5

Visual transduction

Back 5

“Visible” light forms just one part of the spectrum of electro-magnetic radiation

Front 6

What is the wavelength of visible light?

Back 6

Just below 400nm to just above 700nm

Front 7

What is wavelength?

Back 7

The distance from one energy peak to another

Front 8

What is intensity?

Back 8

Amplitude. How much energy is transmitted. How bright something is.

Front 9

The colour white ____ all radiation

Back 9

Reflects

Front 10

The colour white ____ all radiation

Back 10

Reflects

Front 11

The colour black ____ all radiation

Back 11

Absorbs

Front 12

How do we perceive colour?

Back 12

As light hits a surface or object, some wavelengths are absorbed while others are reflected. The wavelengths that are reflected enter our eyes and we perceive the colour the wavelength produces

Front 13

What does your retina contain?

Back 13

Light-sensitive receptor cells which are sensory neurons called photoreceptors

Front 14

What do photo-receptors in the retina contain?

Back 14

Photo-pigments that react to light, causing a chemical change in the cell that results in neural activity.

Front 15

How do the lens of your eyes change to focus light onto your retina?

Back 15

For near objects, the lens become shorter and fatter to focus light onto your retina.

For farther objects, the lens become taller and thinner to focus light onto your retina.

Front 16

What is the reflex called that changes the shape of your lens?

Back 16

Accommodation.

Front 17

Receptor cells: rods

Back 17

- more sensitive than cones

- night vision, work in low-light conditions

- you can see slightly better out of the corners of your eyes at night than straight on.

- make up 120 million rod cells out of 126 million receptor cells in your eyes

- they are located around the edge of your eyes

Front 18

Receptor cells: cones

Back 18

- make up 6 million of the 126 million receptor cells in your eyes.

- central vision (straight on)

- less sensitive than rods

- allow you to see fine details because you can only see details if the object is right in front of you

- colour vision

- cone cells don’t work well in the dark therefore, it’s harder to tell the colour of things

Front 19

Describe the visual information pathway

Back 19

Information passes through the optic nerve, over the optic chiasm (where signals cross between the hemispheres) and to the lateral geniculate nucleus (LGN). The LGN is a relay centre in the thalamus for the visual pathway. It receives sensory input from the retina.

Front 20

Prosopagnosia

Back 20

The inability to process faces.

Front 21

Visual agnosia

Back 21

Inability to recognize certain types of objects, despite seeing their shape

Front 22

Akinetopsia

Back 22

Inability to perceive movement. The item disappears when it moves and reappears when it stops moving.

Front 23

Akinetopsia

Back 23

Inability to perceive movement. The item disappears when it moves and reappears when it stops moving.

Front 24

Different cone cells responsible for colour vision

Back 24

One that is responsive to short wavelengths of light (420nm~ blue) one to medium wavelengths (530nm~ green) and one to long wavelengths (560nm~ red)

Each type contains a different type of photopigment

Front 25

Explain After-images and how they work

Back 25

When you stare at certain colours for long enough, when they disappear, an after-image of another colour appears.

For one colour, that colour will increase while another decreases.

Front 26

Why can’t we see infrared even though its wavelengths are so close to those of visible light?

Back 26

Our eyes only have the photopigment that react to visible light.

Snakes can see infrared.

Front 27

Explain bottom-up processing

Back 27

Taking the sensory input and building up a recognizable image from the combination of lines, corners and colours

Front 28

Describe top-down processing

Back 28

Taking our knowledge, beliefs and expectations about the visual scene and using them to help construct a meaningful image.

Front 29

The Gestalt principles : the law of proximity

Back 29

Things that are close together are grouped together.

Front 30

The Gestalt principles : the law of similarity

Back 30

Things that share the same form are grouped together.

Front 31

The Gestalt principles : the law of closure

Back 31

There is a tendency to perceive things as complete objects (wholes not parts)

Front 32

The Gestalt principles : the law of good continuation

Back 32

We prefer to think of objects as having smooth continuous contours, rather than outlines that abruptly change.

Front 33

The Gestalt principles : the law of common fate

Back 33

Objects that move together are grouped together

Front 34

The perception of depth

Back 34

Depth perception is early to develop. We receive only 2D images on our retinas yet our perception is of a world in 3 dimensions

Front 35

Monocular cues to depth : linear perspective

Back 35

Parallel lines converge as they get farther away

Front 36

Monocular cues to depth : atmospheric perspective

Back 36

Far away objects are bluish and hazy

Front 37

Monocular cues to depth : texture gradients

Back 37

The texture of closer objects is coarser and rougher than the texture of objects that are farther away.

Front 38

Monocular cues to depth : Relative height

Back 38

Objects that are higher up in the visual field tend to be further away (at least, below the horizon)

Front 39

Monocular cues to depth : motion parallax

Back 39

In front of the focal point, closer objects appear to move faster than ones that are further away. These objects move against the direction of motion. Objects behind the focal point move with the direction of motion.

Front 40

Binocular cues to depth : retinal disparity

Back 40

The image from your right eye differs slightly from the image from your left eye. This can be used to judge depth.

Front 41

Binocular cues to depth : convergence

Back 41

Your eyes turn inwards to focus on objects that are closer to you.

Front 42

Size perception

Back 42

The size that you perceive something as being depends on a combination of its retinal size (bottom-up processing) and how far away you perceive it as being (based on top-down assumptions)

Front 43

Perceptual illusions : apparent size

Back 43

Because perceived size is a combination of something’s retinal size and how far away it seems, by manipulating various depth cues, we can create illusions that fool your system into “seeing” objects as larger than they really are.

Front 44

What is sound?

Back 44

A form of physical energy caused by vibrations causing waves of molecules in some substance (usually air)

Front 45

How is the frequency of sound determined?

Back 45

It is determined by the rate of vibration. This is experienced as pitch and measured in Hertz.

High frequency = short wavelength and higher pitches

Low frequency = long wavelengths and low pitches

Front 46

Amplitude

Back 46

A measure of the energy imparted to the medium’s molecules. Amplitude is experienced as loudness and measured in decibels.

Front 47

What does the pinna in the human ear do?

Back 47

It helps to focus sound into the auditory canal.

Front 48

How does sound travel through the human ear?

Back 48

The sound reaches the eardrum (tympanic membrane) and causes it to begin vibrating. The vibration is transferred to the 3 bones of the middle ear (hammer, anvil and stapes). These bones magnify the vibration and pass it to the inner ear where the cochlea receives it.

Front 49

Describe the steps of transduction in the cochlea

Back 49

When the stapes vibrates and passes that vibration into the cochlea through an opening, the vibration in the cochlea causes fluid to move which stimulates receptor cells. This starts turning into electrochemical messages.

Front 50

What happens in the basilar membrane within the cochlea when vibrations enter the ear?

Back 50

High frequencies will cause a peak that happens right at the beginning of the cochlea. It peaks and dissipates quickly.

Medium frequencies will travel past the high frequency receptors, stimulating them a little and then peaking in the middle of the cochlea and dissipates before it gets to the low frequency receptors.

Low pitches and slow frequencies travel through the medium and high frequency receptors, stimulating them but only peaking later into the cochlea and then dissipating.

Front 51

The auditory cortex

Back 51

Neural activity produced in the cochlea eventually reaches the auditory cortex.

Crossing over happens which is when auditory input from your left ear is processed in your right temporal lobe and vice versa.

There is bottom-up processing happening as cells in the auditory cortex combine input to recognize more complex sounds such as human speech.

Front 52

Describe the process of sound localization.

Back 52

The brain uses the fact that we have 2 ears to help us to localize sources of sounds. Sounds that come from the side will reach our ears at different times with different intensity levels. The difference in timing can be as small as 6 hundredths of a second.

Sounds are much harder to tell the direction of when they come from directly in front of behind us since the sound waves will reach both of our ears at the same time.

The shape of the pinna also helps us to work out where sounds are coming from vertically.