Psychology Unit 2

Definition of sensation?

The transduction of the physical world into neural impulses

Definition of perception?

Binding sensory impulses into a representation of the world

What is the sensory system?

A reality detecting device

What is the perceptual system?

A reality manufacturing device

What is the visible spectrum of light waves for humans?

380-740nm

What does wavelength determine?

Colour

What does amplitude determine?

Brightness (low a = dim light)

What determines the colour of something?

The wavelength of light it does not absorb.

What is the sclera?

White part of the eye that maintains eye shape

What is the cornea?

Transparent & focuses 66% of light

What is the aqueous humour?

• Fluid between the cornea and iris

• provides corneal shape

What is the iris?

Colour & regulates the light entering the eye

What is the function of the pupil?

Allows light into the eye

What is the lens?

• Changes shape

• Focuses 33% of light

What is pupillary response?

• Dilates in dim light (large pupil)

• Constricts in bright light (small pupil)

What is the factor that the visual system is senstive in light levels

100 million

How does the lens accomodate for near objects?

becomes thick

How does the lens accomodate for far objects

becomes thin

What is presbyopia?

• Lens no longer thickens (can’t see close)

What are cones?

Light detecting cells (ability to percieve colour)

What are rods?

• Involved in vision of dimly lit environments

• Perception of movement in periphery of visual field

What is the optic nerve?

Where axons from the retinal ganglion converge

What is the function of the optic nerve?

Carries visual info from the retina to the brain

What is the dorsal stream?

Where/how pathway → location in space

What is the ventral stream?

What pathway → object identification & recognition

What is the route to vision?

Retina -→ lateral geniculate nucleus → primary visual cortex →association cortex

What colour do short cones see?

blue

What colour do medium cones see?

green

What colour do long cones see?

Red

What are the types of photoreceptors?

Rods & Cones

What is the pigment in rods?

Rhodopsin

What is the pigment in cones?

Photopsin

Where in the eyeball is there a high density of photoreceptors?

In the fovea

What is the trichromatic theory of colour vision?

That all colours in the spectrum can be produced combining red, green, & blue

What disproved the trichromatic colour theory?

After image

What is the opponent-process colour theory?

That colour perception is controlled by opposing pairs

What does Gestalt psychology reveal?

How the brain binds features together for perception

What is size consistency?

Different retinal image size, but same perceived object size

What is the absolute threshold?

The intensity of a stimulus that allows an organism to just barely detect it

What is sensitivity?

The ability of an individual to detect presence or absence of signal?

What is the response bias?

The tendency to respond “yes” to trials

What is the difference threshold?

Measures the minimal change required to tell 2 different stimuli apart

What are subliminal stimuli?

Events that occur below the absolute threshold of which we are not conscious

What is blindsight?

People who are blind can respond to visual stimuli without consciously seeing them

What is bottom-up processing?

Integrating sensory info from environmental stimulus

What is top-down processing?

Integrating info from knowledge & expectancy

What is sensory adaptation?

The lack of percieving stimuli that remains constant over period of time

What is inattentional blindess?

The failure to notice something compeltely visible due to the person attending to something else

What is timbre?

A sound’s purite

What is frequency?

The number of waves that pass a given point in a certain time period (higher amplitude = louder sounds)

What is an afterimage?

The continuation of a visual sensation after removal of the stimulus

What is depth perception?

Ability to percieve spatial relationships in 3D space

What is binocular vision?

• The ability to integrate information to produce a 3D image

• Produced in the visual cortex

What is binocular disparity?

Different view of the world each eye recieves