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Perception > W2: Body Senses > Flashcards

W2: Body Senses Flashcards

1
Q

What are the different modalities of body senses?

A

Body Senses
Somatosensation (touch), proprioception (body position), kinesthesis (body movements), nociception (pain) and equilibrioception/vestibular sense (balance & spatial awareness)

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2
Q

What is the one body sense has different neural pathways and processing than the other body senses?

A

Body Senses
Vestibular sense (equilibrioception)

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3
Q

Somatosensation

A

Body Senses
‘Touch/haptics detects “physical properties” of a stimuli’s surface (e.g. texture and temp)
Very sensitive system - lips and finger tips most sensitive
Loss of touch is dangerous as hazardous surfaces will damage tissue without feeling it
^more unaware of kinesthesis and proprioception (loss is even more impairing)

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4
Q

Mechanoreceptors

A

Body Senses: Somatosensation: Physiology
Are receptors that detect mechanical properties which contributes to somatosensation, proprioception, kinesthesis, nocioception and equilibrioception.

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5
Q

Tactile Receptors

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors
underneath the skin (+deeper) and sense pressure, vibration and stretch. ‘Each receptor structure reflects its “response to mechanical stimulation” and closes off nerve endings

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6
Q

Pacinian Corpuscles

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: Tactile
onion appearance w/ fluid btwn layers - receptor response occurs when deformed from stimulation in the form of vibration - high freq response (250-350 Hz) to dynamic stimulation. Specialisation to higher thresholds (as location is deep under skin) - senses pressure and stretch of skin

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7
Q

Ruffini’s Corpuscles

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: Tactile
respond slowly and to more stable stimuli. Specialisation to higher thresholds (as location is deep under skin) - senses stretch of skin

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8
Q

Merkel’s disks

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: Tactile
respond slowly and to more stable stimuli. Specialised to light touch (low thresholds due to being right under skin)

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9
Q

Messiner’s Corpuscles

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: Tactile
average temporal response (30 - 50 Hz). mod detects dynamic stimulation. Specialised to light touch (low thresholds due to being right under skin)

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10
Q

Proprioceptors

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors
“in muscles (muscle spindles), tendons, and joints mediating perception of body position (proprioception) and movement (kinesthesis).”

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11
Q

Muscle Spindles

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: proprioceptors
‘4-8 specialised fibers encapsulated in tissue - sensory nerves axons connect to fibers to send info on muscle contraction (determined by distance between loops of spindles) and length - The more precisely and accurately a muscle needs to move, the more spindles it has’. Contraction spikes spindles activity.

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12
Q

Golgi Tendon Organs

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: proprioceptors
activated by muscle tendon

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13
Q

Joint receptors

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: proprioceptors
“respond to joint position”

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14
Q

Thermoceptors

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors
are free nerve endings embedded in skin which detect temperature. Combination of activity between the two fibers reflect the level of temperature

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15
Q

Warmth vs Cold Fibers

A

Body Senses: Somatosensation: Physiology: Mechanoreceptors: Thermoceptors
indicate rise vs fall in temperature

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16
Q

Dorsal root ganglia

A

Body Senses: Somatosensation: Physiology: Pathways
houses sensory neurons that convey neural responses from mechanoreceptors. Receptor potential travels along the axon and transfers down one of the following routes to the brain.

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17
Q

Spinothalamic Pathway

A

Body Senses: Somatosensation: Physiology: Pathways
slowly transfers thermoreceptive signals from free nerve endings to thalamus and primary somatosensory cortex

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18
Q

Lemniscal Pathway

A

Body Senses: Somatosensation: Physiology: Pathways
group of axons stop in spinal cord, others end in the brainstem -> send projections to the thlamus -> “thalamic neurons send axons to the primary somatosensory cortex for cortical processing”.
Mechanoreceptor axons are much faster (“conduction velocities = 20m/s) in this pathway as theyre myelinated (covered in plastic) - *why you feel contact of water drop before temp
The additional pathway for mechanoreceptors uses info independent of the brain and quickly sends it straight to the muscles for quick reflexes that remove us from hazards

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19
Q

Knee jerk reflex

A

Body Senses: Somatosensation: Physiology: Pathways
each pathway projects to spinal cord for reflexes such as the knee jerk or “withdrawal from painful stimuli”

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20
Q

Microneurography

A

Body Senses: Somatosensation: Physiology: Cortical Rep
using microelectrode to record different mechanoreceptors in nerves of arm or hand - fibers have different receptive fields across the hand

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21
Q

Primary Somatosensory Cortex

A

Body Senses: Somatosensation: Physiology: Pathways
“The primary somatosensory cortex occupies a long, thin strip of cortical surface running from ear to ear across the head”

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22
Q

What are the brain areas involved in somatosensation?

A

Body Senses: Somatosensation: Physiology: Cortical Rep
“The primary somatosensory cortex occupies a long, thin strip of cortical surface running from ear to ear across the head” - ‘thalamic axons project to Brodmanns area 3 and adjacent areas’
^broadmanns area 3 shows highly selective and organised neurons

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23
Q

Receptive field properties for somatosensation

A

Body Senses: Somatosensation: Physiology: Cortical Rep
cells only respond to one receptor.
“Receptive fields cover small area of the body“ - areas overlap which allows you to maintain haptic sense across skin even if brain cells die
Brainstem and thalamus’ synapses of cortical cells connects to axes of neural projections
Cells are direction sensitive
*size of receptive field reflects size of body part

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24
Q

Center surround antagonism/ lateral inhibition

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Receptive Field Properties

Area A = receptive field that excites neural responses when stimulated
Area B = area surrounding receptive field that inhibits neural responses
Point where area A and B converge = no alterations to neural responses.
“the cell’s response is sensitive to very small changes in the position and/ or size of the stimulus.”
If area A and B are both stimulated = slight change of response

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25
Q

Cortical organisation of the somatosensory cortex

A

Body Senses: Somatosensation: Physiology: Cortical Rep
(shaped like a headband from ear to ear) has high degree of order and organization reflected by high levels of processing. Receptor neurons project to the opposite hemisphere of brain.

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26
Q

Somatosensation: vertical organisation

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Organisation
6 layers which differ by “cell number, density and morphology”. Thalamic axons end in layer 4 of brodmanns area 3 to project cells to surrounding areas.

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27
Q

Somatosensation: cortical column

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Organisation
“A group of cells lying within a block extending perpendicular to the surface of the cortex that share a common response property, such as receptive field location or stimulus preference - therefore responding to the same receptor.” neighbouring cells receptive field locations overlap.

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28
Q

Somatosensation: somatotopic organisation

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Organisation
adjacent cortical areas reflect adjacent receptive fields/body parts. ‘“Neighbouring cells have closely related properties”.

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29
Q

Somatosensation: horizontal Organisation

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Organisation
travelling horizontally across the somatosensory cortex “there is a very orderly progression in the part of the body covered by the neurons’ receptive fields.”

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30
Q

Somatosensation: Detection

A

Body Senses: Somatosensation: Perception
type of fibers present determines what frequency level of vibration that the receptor responds to - ‘fiber type reflects a “specialised channel” which conveys info about a specialised frequency range’ (4 channels - 4 fibers)

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31
Q

Somatosensation: Channels

A

Body Senses: Somatosensation: Perception: Detection
specified processing routes that carry specified information

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32
Q

Somatosensation: JND/Discrimination threshold

A

Body Senses: Somatosensation: Perception
between touch varies among different body parts.
Lowest threshold/JND on tongue and hands - discriminate between points 2-3mm apart
Highest threshold/JND on back and legs (50mm diff)
^reflects cortical magnification/representation and receptive field size

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33
Q

Somatosensation: Two point acuity

A

Body Senses: Somatosensation: Perception: discrimination
Testing discrimination of two points of pressure on the skin using 2AFC or yes/no procedure (intervals of one poke and two point poke to prevent participants bias) - increase distance between two points until discrimination threshold (usually getting it right after 75%) is established

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34
Q

Somatosensation: Sensation

A

Body Senses: Somatosensation: Perception
fibers relate to different sensations. - cant assume causation
Depending on freq., stimulation to the RA and PC fibers = tapping, flutter, vibration or tingling
SAI stimulation = sustained pressure
SAII (stretching) stimulation = no sensation

35
Q

Somatosensation: Population Coding

A

Body Senses: Somatosensation: Perception: Sensation
sensation results from combo of activity across fibers (e.g. high freq PC stim and low freq RA stim = vibration)

36
Q

Somatosensation: Texture Perception

A

Body Senses: Somatosensation: Perception
texture is perceived by spatial and temporal features. Freq and amplitude of vibration conveys the textures features

37
Q

Somatosensation: Tactile Texture Perception: spatial vs temporal

A

Body Senses: Somatosensation: Texture Perception
Spatial: size shape and density of individual features that make texture
Temporal: sensed by the vibration created when moving skin across surface. Features include bumps and grooves
Tactile texture perception: theory which proposes that “coarse textures are only encoded by their spatial features and fine textures are only encoded by temporal features - *tested and only applies to coarse textures

38
Q

Somatosensation: Object Recognition

A

Body Senses: Somatosensation: Perception
Object Recognition: high and quick recognition rates independent of visual aid
Ventral: regions are involved in recognising object (front and lower parts of brain, e.g. temporal lobe)
Dorsal: regions are involved in locating object (back and higher parts of brain, e.g. parietal lobe)

39
Q

Somatosensation: Haptic Perception

A

Body Senses: Somatosensation: Perception: Object Recognition

Haptic Perception: “The perception of shape, size, and identity on the basis of touch and kinesthesis.”

40
Q

Equilibrioception

A

Body Senses
“Information about the orientation and movement of the body (aka balance) with respect to the external environment is vital for normal bodily function.”

41
Q

Equilibrioception: Vestibular stimuli

A

Body Senses: Equilibrioception/Vestibular Sense
axes and planes of head movement
Gravity: “orientation with respect to gravitational vertical (up and down)” (tilt)
Acceleration: “change of velocity/speed or direction” (linear or rotational)

42
Q

Vestibular Organs

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology
“A fluid-filled organ (with canals and otolith organs) lying in a deep cavity on the side of the skull (one on each side); it houses receptors that provide information about the orientation and movement of the body relative to the external environment.”

43
Q

Vestibular Receptors

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology
mechanoreceptor hair cells that responds (“about movement and body location in relation to external environment”) when cilia is displaced by external forces around the head. Each receptor consists of one kinocilium and a group of stereocilia.
*hair cells axons dont create action potentials - “Instead, presynaptic active zones around the base of each hair cell make synaptic connections with afferent nerve cells forming part of the VIIIth cranial nerve.” hair cells send neurotransmitter along synaptic connection when stimulated which creates action potential in sensory neurons
Spontaneous activity = 110 spikes/sexond

44
Q

Vestibular Receptors: kinnocilium and stereocilia

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology
Kinocilium: “The single, tall, hair-like structure projecting from each vestibular receptor.”
Stereocilia: “The small, hair-like structures projecting from each vestibular receptor to one side of its kinocilium; they are connected to the kinocilium by fine filaments.” ‘they decrease in size as they distance away from kinocilium’
*stereocilia moves towards kinocilium = depolarize hair cells, increase sensory neurons activity
stereocilia moves away kinocilium = hyperpolarize hair cells, decrease sensory neurons activity
^”deflection to the left causes excitation, and deflection to the right causes inhibition.”
High level of spontaneous activity “so the firing rate of vestibular nerve fibers can accurately reflect the change in receptor potential, increasing or decreasing in accordance with the movement of the cilia.” - this response reflects the acceleration/tilting of head

45
Q

Vestibular labrynth

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology
Each organ/vestibular labyrinth in each inner ear (name for connected canals and otolith organs). Vestibular organs connect to cochlea via the 8th cranial nerves. Cilia in vestibular canals convey neural responses when displaced by fluid (caused by acceleration of head). Gravity displaces cilia in otolith organs
Vestibular labrynth: in the inner ear include the otolith organs (utricle and saccule) and three semicircular canals (posterior, anterior and lateral/horizontal) surrounded by fluid.

46
Q

Otolith Organs

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth
utricle and saccule. Known for transducing equilibrioception. Each have a Sensory epithelium that takes up a small area in each structure, to hold hair cells which release neurotransmitters when displaced

47
Q

Macula

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: OO
patch of hair cells in otolith organs covered by otolithic membrane. Otoconia are weights on hair cells, displacing macula when gravitational force puts pressure on it
Linear acceleration = shift btwn membrane and hair cells = friction displaces hair cells = response about acceleration and tilt.
Hair cells are split in half in utricle and saccule- direction of hair movement reflects excitation/inhibition (direction for e and i alternate on each half of hair cells) - utricle otolithic membrane is horizontal, and vertical for saccule - “arrangement allows the otolith organs to distinguish between opposite directions of shear on the basis of the pattern of excitation.”

48
Q

Otolith organs response to linear acceleration

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: OO: Macula
otolith organs respond to linear acceleration as inertia diplaces hair cells. Friction stops when speed steadies, hair cells decrease to resting potential. Otolith organs send identical info about x axis linear acceleration and pitch head back as it produces the same direction of shearing against macula/hair cells (applies to all tilts and acceleration) - creates oculargravic problem.

49
Q

Semicircular canals (posterior, anterior and lateral/horizontal)

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: canals
The Crista: bundle of hair cells (Crista) in each semicircular canal located inside a gelatinous mass (The cupula - sends rotation signals) along the canal filled with fluid (endolymph). Rotational acceleration = deflect cupula and crista (10 milimicrons of deflection for slow rotation)

50
Q

Semicircular canals: response to rotational acceleration

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: canals
signaled by fluid moving up the canal as it “lags behind”, displacing cupula as it catches up with the head/canal. Three canals help indicate any combo of components. Canals are at right angles to easily signal movement along the axes (also at right angles). Kinocilia in this canal move one way for excitation and inhibition as the fluid passes through. Canals on each side of head work in pairs (kinocilia moves in opposite directions on opposite sides - meaning one side is inhibited and the other is excited to indicate the direction of head movement.)
Canals only respond to angular/rotational acceleration and deflection between fluid and canals ease as rotational accelerations velocity steadies.

51
Q

vestibular stimuli: axes of head movement and components of translation

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: planes & axes

Axes of Head Movement: acceleration
X axis: from front to back of head
Y axis: side to side of head
Z axis: vertical
Three Components of translation: “Linear (translatory) head movements can be split into three components, corresponding to translation along each of the three axes:”
X axis: back and foward
Y axis: sideways
Z axis: up and down

52
Q

vestibular stimuli: planes of head movement and rotational components

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: planes & axes

Planes of Head Movement: tilt
Median Plane: vertical plane from front to back of head
Frontal Plane: vertical plane crossing through each side of head
Transverse Plane: horizontal plane
Three Components of Rotation: “three rotational movements corresponding to the rotation of planes
“Pitch: rotate medium plane around y axis = nod of head
Yaw: rotate transverse plane around z-axis = shake head side to side
Roll: rotate frontal plane around x axis = tilt sideways”

53
Q

vestibular stimuli: natural head movements/degrees of translation

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: labrynth: planes & axes
6 components/degrees of freedom which can be used individually and in combinations when moving head around (e.g. moving head down to tie shoelace = “combines linear downward motion along the x - and z -axes, and rotational movement in the median plane as the head rotates downward.”)
*identifying movements by its components are helpful - signals from translatory components = adjust balance; signals from rotational components = move eyeline
Vestibular responses to natural head movements:
“Otolith organs = info about linear/translational components
Semicircular canals = info about rotational components”

54
Q

vestibular pathways

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways

55
Q

vestibular nuclei

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways
“Large groups of neurons in the brainstem” most fibers terminate here

56
Q

vestibulo-cerebellar system

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways
“regulates the movements that control posture and bodily equilibrium by detecting and reducing differences between intended and actual movements.” Vestibular organs send some straight projections to cerebelllum.

57
Q

The vestibulo-spinal system

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways
sends projections along two tracts to spinal cord
Medial: semicircular canals to neck muscles (controls body posture and head position)
Lateral: Otolith organs to limb muscles (control limb movements that maintain balance)
*synapses connecting motor neurons and vestibular organs = rapid reflexes

58
Q

The vestibulo-occular system

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways
mediates following reflex
Vestibulo-occular reflex: “eye movements that compensate for head movements… caused by imbalance of firing rates between left and right vestibular organs” nothing to do w/ higher brain areas

59
Q

vestibular perception

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
Small cortical representation in comparison to other senses but works with vision to understand body position and movement relevant to the environment.
‘Conscious experience only happens when theres a discrepancy between visual and vestibular info (can = confusion, disorientation and nausea”)’

60
Q

Vertigo

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
perception of movement when stable. “Cause = mismatch between somatosensory, vestibular and visual responses in CNS”. dizziness, nausea, postural instability and vomiting.
Height Vertigo: lack of motion parallax/visual signals at certain heights which interferes with posture corrections, causing nausea.
Motion Sickness: “some responses indicate motion while others indicate stationary”
Postural Alcohol nystagmus: small involuntary eye movements and vertigo occur when lying down after acute alcohol consumption as the alcohol thins out the fluid. (think about when youre drunk and lie down)

61
Q

Oculogyral Illusion

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
when rotation stops and the “illusionary sense of body movement, loss of equilibrium, visual movement in stationary objects and reflexive movement of the eyes”. Caused my semicircular canals - “forward” momentum of fluid deflects cupula when head stops rotating (last 30-40 secs while vestibular system decreases to resting potentially)

62
Q

Coriolis Effects

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
when head rotates at different axis to body when spinning causes mismatch of info between vision and otolith organs = nausea and false feeling of head tilting.

63
Q

Oculogravic Illusion

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
“Illusory tilt that is perceived during linear acceleration” due to otoliths organs inability to distinguish between tilt back and vertical linear acceleration.

64
Q

Vection

A

Body Senses: Equilibrioception/Vestibular Sense: Perception
“The illusion of body motion caused by visual stimulation, resulting in nausea”

65
Q

Somatosensory homunculus: Cortical magnification and somatotopic organisation

A

Body Senses: Somatosensation: Physiology: Cortical Rep: Organisation
Somatotopic Organisation: adjacent cortical areas reflect adjacent receptive fields/body parts. ‘“Neighbouring cells have closely related properties”.
Cortical Magnification: Cortical surface size devoted to body part reflect the the importance of the body part rather than the size.
Somatosensory Humunculus: is a diagram of somatotopic organisation & cortical magnification of the somatosensory and motor cortex (showing similar organisation - may reflect their important connection in everyday movements)

66
Q

Illusions

A

use of “colour, light and patterns” to create a perception that doesn’t match the true image. It tell us how vision works.

67
Q

After Effects

A

is the effect on a second stimulus when perceived as different than the true image due to previous adaptation to the first stimulus. Short time to adapt, aftereffects can last from seconds to minutes - effects fade when you move eyes to another stimulus.

68
Q

Size Illusion

A

Size illusions: depth is perceived by the size it takes up on the retina. The component that takes up more space on retina due to closer distance is perceived as smaller than the component further away “compensates for distance related changes in image size“. misapplied constancy scaling = when illusions cause you to incorrectly apply constancy scaling, which is the cause of the illusion itself (this applies to size and shape illusions)
Ponzo Illusion:
Muller-Lyer illusion

69
Q

Shape illusions

A

Shape illusions: strategic placement of lines make people perceive a bend or tilt in a straight line (form of misapplied constancy scaling).
Hering Illusion:
Poggendorff Illusion:

70
Q

orientation illusions

A

lines are falsely perceived as tilting more than they actually are.

71
Q

The Troxler Effect

A

staring at the dot in the sharp circle causes cells that are tuned to the dark surrounding area of the circle to rapidly fire, indicating that the stimulus’ colour intensity has altered across the space. The gradual shift in shade of colour with the blurred line causes a much more reduced rate of firing. When fixating your gaze on the black dot, cells will adapt by further lowering of the firing rate to the same rate as the cells tuned to the darker background, causing the same colour to appear throughout the blurred circle. Moving your gaze resets the aftereffect as moving your eyes around an image is supposed to prevent adaptation (as it makes sure that different cells are being stimulated by different parts of the stimulus - otherwise things we look at would always eventually disappear from out perception).

72
Q

Motion Aftereffect

A

removing a stimulus that has been adapted to with motion moving inwards leaves the cells tuned to the opposite motion at a higher firing rate (because inward cells have dropped to below baseline firing level) making the test stimulus appear to be expanding in the opposite direction. This is because motion detectors are in pairs - whatever is firing more causes that motion its tuned to to be perceived.

73
Q

Orientation (Tilt) Aftereffect

A

looking at a stimulus that has tilts one way fire the cells tuned to that angle. Once adapted and the tilted stimulus is removed the firing rate of the these decreases to below baseline level - because they are now firing lower than baseline, the cells tuned to the opposite angle are now firing at a higher rate causing the test stimulus (straight lines) to be perceived as tilted in the opposite angle to the initial stimulus.

74
Q

Colour Aftereffect

A

adapting to the three different colour channels (red/green, blue/yellow, black/white - cell firing increase = one colour, decrease = opposite colour ) - once adapted stimulus is removed, the cell firing rates increase or decrease to the opposite end of the scale, causing the paired colour to appear in its place (why the black background turns white when looking at a white surface)

75
Q

The vestibulo-thalamic system

A

Body Senses: Equilibrioception/Vestibular Sense: Physiology: Pathways
transfers cortical projections about conscious equilibrious perception (parietal lobe processes these signals). “strong right hemispheric dominance, consistent with this hemisphere’s role in spatial attention and orientation”

76
Q

Ambiguous illusions

A

Ambiguous illusions: are actively reconstructed into the most plausible percept based on prior knowledge (top-down processing of visual images - prev knowledge and higher thought processes influence the way an image is perceived)
Bistable figures
Illusory Contours

77
Q

Bistable figures

A

ambiguous images that can be interpreted as two different percepts - brain selects most plausible percept

78
Q

Illusory Contours

A

images where shapes are strategically placed so that people the edges allow us to perceive a shape that is not there. ambiguous illusion

79
Q

Ponzo Illusion:

A

the differing distances between the end of each horizontal lines and the parallel lines surrounding them influences the mind in perceiving them at different depths. Image is supposed to shrink as it furthers distance from retina (to be perceived as maintaining size) - therefore same length lines at “differing distances” make it appear that the above line is larger than the closer line. size illusion

80
Q

Muller-Lyer illusion

A

direction of arrow on ends of lines makes regular structured arrow appear shorter than inverted arrow in order for them to be perceived as being at different depths. size illusion

81
Q

Hering Illusion

A

when the background appears close to the top and bottom of the parallel lines, but distant from the middle of the parallel lines, this causes a misapplied constancy scaling , which causes the parallel lines to be perceived as bulging in the middle or by overestimating the size of the angles in the middle. shape illusion

82
Q

Poggendorff Illusion

A

shape illusion. a straight line crossing through parallel lines are both trigger a misapplied constancy scaling, causing the two intersecting lines to appear to not line up when the actually do. This is due to people overestimating acute angles, perceiving the intersecting lines as slightly angled upwards - meaning that they wouldn’t connect at a proper 180 degree angle.

83
Q

Zoner illusion

A

Orientation (tilt) Illusion: our tendency to overestimate acute angles makes parallel lines appear tilted.

Perception (5 decks)

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