it is about the psychological mechanism of perception

2. TOPIC OF
PRESENTATION

3. WHAT IS
PERCEPTION???
“Perception can
be defined as our
recognition and
interpretation of
sensory
information.”

6. .
FOR EXAMPLE:-
Lets look at our perception of words.
Each letter of alphabet is in itself a
singular letter. When we perceive
words, we think of them as one
singular unit that is made up of smaller
parts called LETTERS. It is through
this organization of letters into words
that we are able to make something
meaningful. That is, we perceive an
entire word and this word has a
specific meaning that can be found in

9. Although intimately related,
sensation and perception play
two complimentary but
different roles in how we
interpret our world.
Sensation refers to the
process of sensing our
environment through touch,
taste, sight, sound and smell.
This information is sent to our
brains in raw form where

10. And

11. Perception is the
way how a person
understands
something
Reality is the
truth and actual
existence of
something

12. 12
Perception’s three basic processes:
Selection
Organization
Interpretation

13. • Objects change in
our eyes constantly
as we or they
move….but we are
able to maintain
constant
perception
• Shape Constancy
• Size Constancy
• Brightness
Constancy

14. It is recognition that
an object remains the
same size even
though the retinal
image of the object
changes
14

15. Flat Front
View
3D Side
View

16.  The perceived size of an object remains
constant, despite changes in its retinal size
16

17. 17
We perceive an object as
having a constant
brightness even while its
illumination varies

18. Types Of Perception :
Form
Perception
Depth
Perception

20. Form perception
is the recognition of objects
in a particular form within a
certain environment.
An object is perceived by the retina as a two
dimensional image, but the image can vary
for the same object in terms of the context
with which it is viewed, the apparent size of
the object, the angle from which it is viewed,
how illuminated it is, as well as where it
resides in the field of vision.

21. Figure and ground
 The organization of the visual field into objects (the
figures) that stand out from their surrounding (the
ground)
Grouping
 The perceptual tendency to organize stimuli into
coherent groups
 Grouping principles: proximity, similarity, continuity,
closure etc
21

22. Figure and ground
Organizational Behavior / Perception 22

23. •Gestalt psychologists focused on
how we GROUP objects together.
•We innately look at things in groups
and not as isolated elements.
- group objects that are
close together as being part of same
group.
- objects similar in
appearance are perceived as being
part of same group.
- objects that form a
continuous form are perceived as
same group.
- like top-down
processing…we fill gaps in if we can
recognize it.

24. DEPTH PERCEPTION

25. WHAT IS DEPTH PERCEPTION
The visual ability to
perceive the world in three
dimensions (3D) though
the images formed on our
retina are two
dimensional.
Eleanor Gibson and
Richard walk regarded the
ability of depth perception
as innate.

26.  The ability to see
three dimensional
space and to
accurately judge
distances
 Depth cues for
depth perception:
binocular cues,
monocular cues
26

27. EXAMPLE
EVEN though this painting is
on a flat canvas you still
percieve it in 3D. Why???

28. Types of depth or distance perception
1)Binocular cues
2) Monocular cues

29. Binocular Cues
Binocular depth information is dependent
on information from both eyes, not one..
Binocular depth cues are clues about
distance based on the differing views of the
two eyes
There are two types of
binocular cues :-
Retinal disparity
convergence

30. Retinal
Disparity:- The
image your right eye sees is
different than your left eye
because they are a small
distance apart. The image
you see using both eyes is the
two images merged.

31. Convergence
Because the two eyes converge on an
object when we are viewing it, the brain
can use the angle of convergence as a cue
to how far away that object is.
For example ,

32. Monocular cues:-
Cues received by one eye.
When we have to judge a person wheter he is
100 feet or 100 yards away, the retinal
disparity is slight, we have to depend on
monocular cues.
Monocular cues are the following:-
1) Relative size
2)Linear perspective
3)Overlap and interposition of objects
4)clearness of details
5)Change in colour
6)Relative height
7)Relative brightness
8)Accommodation of the eye

33. 1)Relative size
According to law of visual angle,
.
As an object
moves farther
away its image
becomes
smaller.
The object
itself is of
same
size.....
BUT
The size of retinal
images is shortening
relatively.

34. Example
If we see the same
cars from the top of
Minar-e-Pakistan or
Shahi mosque, the
apparent size of
those cars looks
smaller.

35. 2)Overlap or interposition of objects
If one thing covers other,
the covered thing is
perceived farther and the
coverer seems nearer .

36. Example
If a tree covers
some position of a
house , the tree is
perceived nearer
and house farther.

37.  Light and shadow
Nearby objects
reflect more light to
our eyes. Thus,
again two similar
objects, the dimmer
one seems further
away
37

38.  Relative height
Near objects are low in
the visual field; more
distant ones are higher
up
38

39.  Relative size
If separate objects
are expected to be
of the same size,
the larger one are
seen as closer
39