Midterm 1 - Unit 5, Sensation & Perception

Question 1

Color constancy

Answer 1

• Brain’s ability to recognize color of an object as being the same even under different lighting conditions
• Brain adjusts its perception of color to hold it constant, accounting for changes in lighting conditions & other contextual factors (e.g., shadow

Question 2

Stimulus

Answer 2

• something that elicits a reaction from our sensory system
• Light (vision)§Sound waves (hearing)§Mechanical pressure, vibration, temperature, pain (touch)§Chemicals in food and drink (taste)§Airborne chemicals (smell

Question 3

Sensation

Answer 3

process by which sensory organs detect environmental stimuli & convert them into electrical signals for the nervous system

• The process by which our sensory organs receive stimulus energies from the environment and transduce them into the electrical energy of the nervous system.

Question 4

Transduction

Answer 4

• The transformation of sensory stimulus energy from the environment into neural impulses.
• E.g., light entering your eyes is converted into neural impulses by specialized cells

Question 5

Perception

Answer 5

• brain’s interpretation of these electrical signals to create an internal representation of the world

Question 6

Bottom-up vs top-down processing

Answer 6

bottom-up:
- Interpretation relies both on raw sensory data

top-down:
- our prior experience, knowledge & expectation

Question 7

psychophysics

Answer 7

• study of the relationship between the physical qualities of stimuli (physics) and our mental experience of them (psyche)
• the physical qualities of of stimuli and our mental experience of those stimuli is called psychophysics
• physics for the external physical stimuli and psyche for for our mental experience

Question 8

absolute threshold of awareness

Answer 8

• minimum amount of stimulus that can be detected at least 50% of the time

Question 9

sensitivity

Answer 9

• Sensitivity in psychology refers to how good someone is at detecting a stimulus, like a sound, light, or touch.
• If you have high sensitivity, you can notice even small or faint stimuli. If you have low sensitivity, you need a stronger stimulus to detect it.
• sensitivity to the absolute threshold refers to the smallest amount of stimulus (like light, sound, or touch) that a person can detect 50% of the time. It’s the minimum level at which you become aware of something.

Question 10

signal detection theory

Answer 10

• An approach to measuring thresholds that takes into account both the intensity of the stimulus and psychological biases for a more accurate assessment.
• how we make decisions under conditions of uncertainty, such as when we are listening for a faint sound or looking for a light in the distance

Question 11

liberal bias and conservative bias (signal detection theory)

Answer 11

liberal:
- Higher rate of hits, but also false alarms

conservative:
- Lower rate of false alarms, but also hits

Question 12

just-noticeable difference/difference threshold

Answer 12

• smallest difference between two stimuli that can be detected at least 50% of the time
• The minimum difference required between two stimuli for an observer to detect a difference half the time.

Question 13

weber’s law/weber’s fraction

Answer 13

• as stimuli get larger, differences must also become larger in order to be detectable
• This means the bigger or stronger the original stimulus, the bigger the change needs to be for you to notice it.
• If you’re holding a 10-pound weight, you might notice a 1-pound increase (11 pounds total). But if you’re holding a 100-pound weight, you might need a 10-pound increase (110 pounds) to notice the difference.
• fraction: The exact ratio for each type of stimulus (like sound or weight).

Question 14

adaptation

Answer 14

• stop noticing a stimulus that remains constant over time

Question 15

properties of light

Answer 15

Wavelength: This is the distance between two peaks of a light wave. It determines the color of light. Shorter wavelengths are blue/violet, and longer wavelengths are red.

Amplitude: This is the height of the wave. It determines the brightness of the light. Higher amplitude means brighter light.

Frequency: This is how many waves pass a point in a second. Higher frequency means more waves and shorter wavelengths.

Wavelength = color
Amplitude = brightness
Frequency = how fast the waves are

Question 16

structures of the eye

Answer 16

cornea
- transparent tissue covering front of eye, focuses light

iris
- opaque, colourful muscle encircling the pupil

pupil
- hole in the iris where light enters the eye

lens
- membrane at front of the eye that focuses incoming light on the retina

accommodation
- adjustments of the lens’s thickness by specialized muscles in order to change the degree to which it bends light

retina
- surface in the back of the eye containing receptor cells specialized for transducing light (photoreceptors)

Question 17

photoreceptors (two kinds)

Answer 17

photoreceptors:
rod
- Photoreceptor cell that primarily supports nighttime vision

cone
- Photoreceptor cell that is responsible for high-resolution color vision

Question 18

visual transduction

Answer 18

• the process by which light is converted into electrical signals in the eye so that the brain can understand and interpret what we see
• Light enters the eye and hits the retina at the back of the eye.
• The retina has special cells called photoreceptors (rods and cones).
  …Rods help you see in low light and black-and-white.
  ….Cones help you see colors in bright light.
• When light hits these cells, it triggers a chemical change that creates an electrical signal.
• This signal is sent through the optic nerve to the brain, where it is processed as an image.

Question 19

rhodopsin

Answer 19

• a light-sensitive protein found in the rod cells of the retina in your eye. It helps you see in low-light conditions.

Question 20

color vision

Answer 20

• comes from cones
• Each cone has one of three distinct varieties of photopigment§Sensitive to short, medium, or long wavelengths (approximately corresponding to blue, green, or red)
• These cones work together to help you see a full range of colors. When light hits the cones, they send signals to your brain based on the combination of red, green, and blue light they detect. The brain then mixes these signals to produce the color you see.
• If red and green cones are activated, you see yellow.
  If all three (red, green, blue) cones are activated equally, you see white.
  In short, color vision is made possible by cones in the eye that detect red, green, and blue light, allowing your brain to mix and perceive different colors.

Question 21

trichromatic theory

Answer 21

• the three types of cone cells work together to produce perception of colour

Question 22

opponent-process theory

Answer 22

• stating that information from the cones is separated into three sets of opposing or opponent channels in the ganglion cell layer.
• explains color afterimages as perceptual opposites, originating from opposite sides of the color circle

Question 23

visual system is described as “hierarchical”

Answer 23

• The brain processes and organizes the data it receives from the retina through hierarchical series of steps of increasing complexity

Question 24

how visual info travels from the eyes to the brain

Answer 24

light hits the eye, turns into signals, travels thru the optic nerve, reaches the brain, processed into a pic

Question 25

feature detectors

Answer 25

• specialized neurons that respond to specific attributes of visual stimulus (e.g., edges, angles, orientation)

Question 26

visual association cortex

Answer 26

• combines incoming sensory inputs with prior knowledge & expectation

Question 27

visual agnosia

Answer 27

• damage to ventral pathway
• where subject is not able to recognize object

Question 28

prosopagnosia

Answer 28

• inability to recognize faces

Question 29

ventral and dorsal pathways

Answer 29

ventral
- processes “what” information
- Responsible for recognizing objects and faces

dorsal
- processes “where” information.
- Responsible for determining location and the perception of movement

Question 30

gestalt psychology

Answer 30

• perspective that we perceive whole, organized patterns & objects
• researchers proposed an alternative framework to explain how the human brain groups various elements together to form objects.

Question 31

gestalt principles (4)

Answer 31

proximity

similarity

closure

good continuation

Question 32

reversible figures

Answer 32

• Demonstrate how our overall perception of an object may differ from the elements from which its perception is derive

Question 33

illusory contours (in relation to top-down processing)

Answer 33

• perceived edges or shapes that are not actually present in the physical stimulus.
• they occur when the brain fills in gaps to create a complete image based on visual cues.
• Illusory contours are an example of top-down processing because your perception is influenced by your brain’s expectations, knowledge, and context rather than just the incoming sensory information. Your brain uses prior experiences and learned patterns to interpret visual input, leading you to “see” shapes or edges that aren’t physically there.

Question 34

binocular and monocular for depth perception

Answer 34

• Image projected on retina is 2-Do
• Brain uses various cues to translate this 2-D image into 3-D perception of real-world object
• Use both binocular and monocular cues

bioncular:
- depth information gathered from the separation between an individual’s two eyes

monocular:
- depth information that can be gathered using just one eye

Question 35

perceptual stability despite sensory variability (size and color constancy)

Answer 35

• Brain accounts for variation in retinal images in terms of distance, and interprets it as a cue for depth
• Objects further away project a smaller image on the retina

Question 36

functions of the components of the ear

Answer 36

outer ear:
- pinna: captures & funnels soundwaves through auditory canal towards the middle ear

middle ear:
- ossicles: tiny bones located between two membranes (tympanic membrane/eardrum & oval window)

inner ear:
- cochlea: A spiral-shaped, fluid-filled structure that converts mechanical vibrations into electrical signals. It contains hair cells that respond to different frequencies of sound.

• vestibular system: a sensory system located in the inner ear that helps us maintain balance, spatial orientation, and coordination. It provides information about head position and movement, which is crucial for maintaining stability and posture.

Question 37

Two Ways We Perceive Pitch

Answer 37

Frequency: Higher frequency = higher pitch; lower frequency = lower pitch.

Timbre: The quality or color of a sound that distinguishes different types of sound production.