Perception, Action, & Development
Hoorcollege 1 (5-11-2019) – perception (H4):
Reality is not what we perceive, perception is a constructive act (inverse optics)
always incomplete images, we fill in what’s there (interpretations)
- Gestalt grouping rules: describing which elements in an image will
appear to group together (good continuation = two elements will tend to
Occlusion
group together if they seem to lie on the same contour) perceptual grouping
(color, proximity, size, meaningfulness, similarity, parallelism, connectedness,
symmetry, context, synchrony (common fate))
Perceptual presence X Physical presence (retinal projection):
- Attention (neglect), camouflage, fading. (no X yes)
- Hallucinations, imagination (dreaming), illusory contours/colors (a
contour/color is perceived, even there is no contour/color). (yes X no)
Illusions:
- Wrong interpretation (wrong depth perception), distraction (attention)
- Moon illusion: de maan lijkt groter aan de horizon dan hoog in de lucht.
Dit komt doordat er veel gebouwen, bomen etc. tussen staan,
waardoor de afstand tot de maan groter lijkt en je hem groter
waarneemt dan hij eigenlijk is.
Object recognition:
- Viewpoint independency: interpretation of an object does not change when the
observer’s viewpoint/projection on retina changes. Structural description from
any view.
Accidental viewpoint: a single visual position that
produces an ambiguous image. It doesn’t
provide enough information to distinguish what
the object is
- Viewpoint dependency: large set of stored images needed, not easily
distinguishable by their parts (complex/natural objects in real world)
- Figure-ground assignment: determining that some object of a figure
belong to the foreground (due to surroundedness, small size,
symmetry, parallelism) and others to the background
- Recognition by component (RBC) theory: objects are recognized by the
identities and relationships of their component parts (nonaccidental features =
feature of an object that do not depend on accidental/exact viewpoints
(geons))
- Template theory: the visual system recognizes objects by matching the neural
representation of the image with a stored representation of the same ‘shape’
in the brain & structural description: a description of an object in terms of the
nature of its constituent parts and the relationships between those parts.
- Multiple levels of categories: animals (superordinate level) dogs, horses,
fish (entry/basic level: the basic level of category for every bird (similar
shapes, similar interactions)) chihuahua & labrador, ice lander & fjord,
, sharks & salmon (subordinate level). Superordinate & subordinate level take
longer
Gestalt grouping principles & completing contours and objects, figure-ground
mechanisms, avoid interpretations of accidental viewpoints
Responsiecollege 1 (7-11-2019) – perceptual cues (H6):
Pictorial cues (monocular cues):
- Occlusion: one object obstructs the view of part of another object (completion
find discontinuities and complete an object)
- Relative size: a comparison of size between items without knowing the
absolute size of either one
- Texture gradient: items of the same size look smaller/narrower when they’re
farther away (Relative height: something higher in the visual field looks farther
away & Aerial perspective: something blurrier in the visual field looks farther
away)
- Linear perspective: parallel lines turn to one (vanishing) point in the middle
- Shadow: can make an object look different
Motion cues:
- Motion parallax: when moving, object closer to you move faster (opposite
direction) than object far away (same direction) based on head movement
Oculomotor cues:
- Accommodation of lenses: thick lens (close) & thin lens (far)
- Convergence: looking at an object nearby (the eyes turn to each other)
- Divergence: looking at an object far away (the eyes turn away from each
other)
Binocular cues:
- Corresponding retinal points: points on the retina of each eye when fixating on
a point in front of you on the horopter, are at the same distance of the fovea in
each eye
- Stereopsis: the impression of depth when viewing objects with both eyes
- Disparity: differences between the images falling on our two retinas. Crossed
disparity (object in front of the horopter) & uncrossed disparity (objects behind
the horopter) causes double vision (diplopia) the larger the disparity, the
greater the distance in depth of the object from the horopter.
Hoorcollege 2 (12-11-2019) – attention (H8 & article Simons & Wang):
Attention: filtering out irrelevant information in order to deal effectively with others and
to avoid overload (selection).
- Visual/auditory attention
- Voluntary X involuntary
Space-based X object based:
- Space-based attention: attention is directed to a specific location in a spatial
representation of the visual field
Hoorcollege 1 (5-11-2019) – perception (H4):
Reality is not what we perceive, perception is a constructive act (inverse optics)
always incomplete images, we fill in what’s there (interpretations)
- Gestalt grouping rules: describing which elements in an image will
appear to group together (good continuation = two elements will tend to
Occlusion
group together if they seem to lie on the same contour) perceptual grouping
(color, proximity, size, meaningfulness, similarity, parallelism, connectedness,
symmetry, context, synchrony (common fate))
Perceptual presence X Physical presence (retinal projection):
- Attention (neglect), camouflage, fading. (no X yes)
- Hallucinations, imagination (dreaming), illusory contours/colors (a
contour/color is perceived, even there is no contour/color). (yes X no)
Illusions:
- Wrong interpretation (wrong depth perception), distraction (attention)
- Moon illusion: de maan lijkt groter aan de horizon dan hoog in de lucht.
Dit komt doordat er veel gebouwen, bomen etc. tussen staan,
waardoor de afstand tot de maan groter lijkt en je hem groter
waarneemt dan hij eigenlijk is.
Object recognition:
- Viewpoint independency: interpretation of an object does not change when the
observer’s viewpoint/projection on retina changes. Structural description from
any view.
Accidental viewpoint: a single visual position that
produces an ambiguous image. It doesn’t
provide enough information to distinguish what
the object is
- Viewpoint dependency: large set of stored images needed, not easily
distinguishable by their parts (complex/natural objects in real world)
- Figure-ground assignment: determining that some object of a figure
belong to the foreground (due to surroundedness, small size,
symmetry, parallelism) and others to the background
- Recognition by component (RBC) theory: objects are recognized by the
identities and relationships of their component parts (nonaccidental features =
feature of an object that do not depend on accidental/exact viewpoints
(geons))
- Template theory: the visual system recognizes objects by matching the neural
representation of the image with a stored representation of the same ‘shape’
in the brain & structural description: a description of an object in terms of the
nature of its constituent parts and the relationships between those parts.
- Multiple levels of categories: animals (superordinate level) dogs, horses,
fish (entry/basic level: the basic level of category for every bird (similar
shapes, similar interactions)) chihuahua & labrador, ice lander & fjord,
, sharks & salmon (subordinate level). Superordinate & subordinate level take
longer
Gestalt grouping principles & completing contours and objects, figure-ground
mechanisms, avoid interpretations of accidental viewpoints
Responsiecollege 1 (7-11-2019) – perceptual cues (H6):
Pictorial cues (monocular cues):
- Occlusion: one object obstructs the view of part of another object (completion
find discontinuities and complete an object)
- Relative size: a comparison of size between items without knowing the
absolute size of either one
- Texture gradient: items of the same size look smaller/narrower when they’re
farther away (Relative height: something higher in the visual field looks farther
away & Aerial perspective: something blurrier in the visual field looks farther
away)
- Linear perspective: parallel lines turn to one (vanishing) point in the middle
- Shadow: can make an object look different
Motion cues:
- Motion parallax: when moving, object closer to you move faster (opposite
direction) than object far away (same direction) based on head movement
Oculomotor cues:
- Accommodation of lenses: thick lens (close) & thin lens (far)
- Convergence: looking at an object nearby (the eyes turn to each other)
- Divergence: looking at an object far away (the eyes turn away from each
other)
Binocular cues:
- Corresponding retinal points: points on the retina of each eye when fixating on
a point in front of you on the horopter, are at the same distance of the fovea in
each eye
- Stereopsis: the impression of depth when viewing objects with both eyes
- Disparity: differences between the images falling on our two retinas. Crossed
disparity (object in front of the horopter) & uncrossed disparity (objects behind
the horopter) causes double vision (diplopia) the larger the disparity, the
greater the distance in depth of the object from the horopter.
Hoorcollege 2 (12-11-2019) – attention (H8 & article Simons & Wang):
Attention: filtering out irrelevant information in order to deal effectively with others and
to avoid overload (selection).
- Visual/auditory attention
- Voluntary X involuntary
Space-based X object based:
- Space-based attention: attention is directed to a specific location in a spatial
representation of the visual field
