Biological Psych - Sensation and perception

Question 1

Perception

Answer 1

Involves the processing, organization, and interpretation of sensory signals in the brain, which results in an internal representation of the stimuli - and your conscious experience of it

Question 2

Sensation

Answer 2

Involves the detection of external stimuli (ex. light, pressure), responses to those stimuli, and the transmission of these responses to the brain

Question 3

Transduction

Answer 3

Process by which sensory receptors pass impulses to connecting neurons when they receive stimulation (ex. pressure on the skin from touch)

Question 4

Absolute threshold

Answer 4

The minimum intensity of stimulation that must occur before you experience a sensation (or the stimulus intensity detected above chance)

Question 5

Difference threshold

Answer 5

The just noticeable difference between two stimuli (the minimum amount of change required for a person to detect a difference 50% of the time)

Question 6

Taste

Answer 6

• Every taste experience is composed of a mix of five basic qualities (sweet, salty, sour, bitter, umami/savoury)
• Smell and texture are also important (remember the taste experience occurs in your brain)

Question 7

Olfactory epithelium

Answer 7

A thin layer of tissue embedded with smell receptors, which transmit information to the olfactory bulb, which is the brain center for smell

Question 8

Orbitofrontal cortex

Answer 8

• Receives info from smell, taste, and visual systems
• Flavour perception

Question 9

Mechanoreceptors

Answer 9

• Respond to mechanical distortion or pressure
• The most sensitive mechanoreceptors are found in the cochlea (responsible for sound transduction)

Question 10

The primary somatosensory cortex

Answer 10

• Connected parts of the body tend to be represented beside each other
  -> Somatotopic organization
• More sensitive regions tend to have more cortical area devoted to them (ex. lips, fingers)
  -> Sensory homunculus

Question 11

Myelinated fibers

Answer 11

“A delta”
Sharp, immediate pain (protection)

Question 12

Lightly/non-myelinated fibers

Answer 12

“C”
Dull, steady pain (recuperation)

Question 13

Gate control theory of pain

Answer 13

For pain to be experienced, pain receptors must be activated AND the neural “gate” in the spinal cord must allow the signals through to the brain
- If the gate is “open”, pain is experienced
- If the gate is “closed”, pain is reduced/prevented

Question 14

Accomodation

Answer 14

Muscles change the shape of the lens, flattening it to focus on distant objects, and thickening it to focus on closer objects

Question 15

Photoreceptors

Answer 15

Convert the energy from light particles (photons) into a chemical reaction that produces an electrical signal

Question 16

Rods

Answer 16

Retinal cells that respond to low levels of light, and result in black and white perception. About 120million in each retina, located along the edges.

Question 17

Cones

Answer 17

Retinal cells that respond to higher levels of light, and result in color perception. About 6million in each retina, located in the fovea.

Question 18

Types of cones

Answer 18

• According to the trichromatic theory, the perception of colour is determined by the ratio of activity among these three types of receptors
  □ S cones -> short wavelengths -> blues
  □ M cones -> medium wavelengths -> greens
  □ L cones -> long wavelengths -> reds

Question 19

Opponent-process theory

Answer 19

• Hering 1920
• Focus on ganglion cells in the retina
• Three opposing pairs (if one colour in the pair is stimulated, the other is inhibited)
  -> Red/green
  -> Yellow/blue
  -> White/black

Question 20

Motion sensitive neurons

Answer 20

Fatigue of certain motion sensitive neurons leads to motion after-effects (the waterfall illusion)

Question 21

Visual transmission

Answer 21

Rods and cones -> bipolar, amacrine, horizontal cells -> ganglion cells/optic nerve -> thalamus (LGN) -> primary visual cortex

Question 22

Dorsal stream

Answer 22

“where”
Specialized for spatial perception, determining where an object is and its spatial relation to other objects

Question 23

Ventral stream

Answer 23

“what”
Specialized for perception and recognition of objects, such as determining color and shape

Question 24

Gestalt principles of perceptual organization

Answer 24

• Figure-ground relationship
• Illusory contours
• Proximity
• Similarity
• Continuation
• Closure

Question 25

Figure-ground relationship

Answer 25

Whatever is not the figure (the focus of visual field) is automatically assigned as background

Question 26

Illusory contours

Answer 26

We tend to perceive contours, even when they don’t exist (but something in the stimulus suggests that they ought to be present)

Question 27

Proximity

Answer 27

The closer two figures are, the more likely we are to group them together and see them as being part of the same object

Question 28

Similarity

Answer 28

We tend to group figures according to how closely they resemble each other

Question 29

Continuation

Answer 29

We tend to interpret intersecting lines as continuous rather than as changing direction radically

Question 30

Closure

Answer 30

We tend to complete figures that have gaps

Question 31

Retinal disparity

Answer 31

Important cue of depth perception, caused by the distance between the eyes, which provides each eye with a slightly different image. The brain uses the disparity between these two retinal images to compute distances.

Question 32

Monocular depth cues

Answer 32

Include occlusion, relative size, familiar size, linear perspective, texture gradient, and position relative to horizon

Question 33

Motion parallax

Answer 33

Objects that are farther away seem to move more slowly that objects that are closer

Question 34

Bottom-up processing

Answer 34

Information is sent from lower-level processing areas to higher level processing areas

Question 35

Top-down processing

Answer 35

Information from higher-level areas can also influence lower, “earlier” levels in the processing hierarchy

Question 36

Hemisphere study

Answer 36

• Left hemisphere vocalizes a response, and it sees what is on the right side of the visual field
• Left hemisphere doesn’t know what the right hemisphere has seen (the rubber duck), so it interprets the left hand’s response (pointing to the bathtub) in a manner consistent with the knowledge it has

Question 37

Interpreter

Answer 37

• A left-hemisphere process that attempts to make sense out of events
• Creates a comprehensible story out of events, provides a narrative, tries to find patterns, relationships

Question 38

Fusiform face area

Answer 38

• Area of the brain that becomes particularly active when people look at faces (some evidence that it is an “expertise” area and not just for faces)