Perception and Illusion

2. The word perception comes from the Latin words, “percipio” meaning
“receiving, collecting, action of taking possession, apprehension
with the mind or senses”.
 Meaning of Perception:

3. Perception:
 Perception is the process of organizing and interpreting
information to give it meaning. Perception provides a
meaningful awareness and knowledge of the world.
 To understand of something in its original position like
shape, colour, and size is called perception.
 Perception means perceiving.
 Giving meaning to the environment around us.

4. There are two key ways we process information that we perceive:
bottom-up processing and top-down processing.
 Types of perception processing:
This refers to processing sensory information from the raw environment
in the brain.
 Bottom Up Processing:
You first notice individual elements of a scene (like colors, lines,
shadows), which then come together to form a meaningful image.
Example:

5. This involves using prior knowledge, memories, experiences, or
expectations to interpret and understand sensory information.
 Top-down Processing:
If you see a vague, ambiguous image, but you expect it to be a
dog, you will likely interpret it as a dog.
 Example:

6.  Nature of perception:
Perception is clearly an outgrowth of sensation.
The sensory experience of the world, which includes how an individual
recognize and interpreter sensory information.
 Perceptual information is gathered from:
• Sight
• Hearing
• Touch
• Taste
• Smell

7. • Perception is the process by which an individual gives meaning to the
environment.
• People‘s actions, emotions, thoughts and feelings are triggered by their
perceptions of their surroundings.
• Perception has been defined in a variety of ways; it basically refers to the
manner in which a person experiences the world.
• Perception is an almost automatic process and works in the same way
within each individual, yet it typically yields different perceptions.
• It is a cognitive and psychological process.
• Perception is the process by which an individual gives meaning to
the environment.

8.  Factors that Influence Perception:
1. Characteristics of the perceiver
2. Characteristics of theTarget
3. Characteristics of the Situation

9. Several characteristics of the perceiver can affect perception. When an individual looks
at a target and attempts to interpret what he or she stands for, that interpretation is
heavily influenced by personal characteristics of the individual perceiver.
The major characteristics of the perceiver influencing perception are:
1.Attitude
2.Motives
3.Interest
4.Experience
5.Expectation
6.Self-concept
 Characteristics of the Perceiver:

10.  Attitude:
The attitude and aptitude of employees influence perception formation. If they have
positive attitudes towards the management, they directly perceive the stimuli given by
management. In the case of negative attitudes, the employees suspect the
management’s approach. Employees of high aptitude have a desire and attitude for
growth. They behave positively toward the management of an organization.
 Motives:
The motives and desires of employees cause them to view stimuli differently as per
their level and angle. Helpful motives of the employees will always assist the
management. If they desire to develop themselves and the organization, they will
perceive objects and situations positively. Employees having low motives will not work
sincerely. The perception will differ depending on different types of motives.

11.  Interest:
The interest of individuals draws more attention and recognition to stimuli. Less
attention and recognition lowers the impact of stimuli or objects on behaviour. If
employees lack interest, behaviour pattern will be less effective, and the perception will
be weak.
 Experience:
The experience of employees results in different levels of perception. A young employee
takes time to understand the object and situation. Experienced employees generally
understand objects quickly and correctly. However, in contradictory situations, it is
difficult to correct aged persons, whereas the young are easily moulded towards
achieving the objectives of the organization.

12.  Expectation:
Expectations distort perceptions. People see what they expect to see. If they see the
object and the situation differently from their expectations, they get frustrated. They are
unable to modify their behaviour.
The employees may expect more pay and so they perceive the management from that
angle. The real stimuli are not properly perceived if expectations exist there on. The
management has to evolve expectations for proper perception.
 Self-Concept:
Another factor that can affect social perception is the perceivers’ self concept. An
individual with a positive self-concept tends to notice positive attributes in another
person. In contrast, a negative self-concept can lead a perceiver to pick out negative
traits in another person. Greater understanding of self allows us to have more accurate
perceptions of others.

13.  Characteristics ofTarget:
Characteristics in the target that is being observed can affect what is perceived.
Physical appearance plays a big role in our perception of others. Extremely attractive
or unattractive individuals are more likely to be noticed in a group than ordinary
looking individuals.
Motion, sound, size and other attributes of a target shape the way we see it.

14.  Physical appearance:
Physical appearance plays a big role in our perception of others. The perceiver will
notice the target’s physical features like height, weight, estimated age, race and
gender. Perceivers tend to notice physical appearance characteristics that contrast
with the norm, that are intense, or that are new or unusual.
 Verbal communication:
Verbal communication from targets also affects our perception of them. We listen to the
topics they speak about, their voice tone, and their accent and make judgements based
on this input.

15.  Non-verbal communication:
Non-verbal communication conveys a great deal of information about the target. The
perceiver deciphers eye contact, facial expressions, body movements, and posture
all in an attempt to form an impression of the target.
Targets are not looked at in isolation; the relationship of a target to its background
influences perception because of our tendency to group close things and similar
things together.

16.  Objects:
Objects that are close to each other will tend to be perceived together rather than
separately. As a result of physical or time proximity, we often put together objects or events
that are unrelated.
People, objects or events that are similar to each other also tend to be grouped together.
The greater the similarity, the greater the probability we will tend to perceive them as a
group.
 Characteristics of Situation:
Change in situation leads to incorrect perception
about a person.

17.  Time:
The situation in which the interaction between the perceiver and the target takes
place has an influence on the perceiver’s impression of the target.
For Example, a person decked up for a party may not be noticeable but the same
dress in office would be noticed distinctly, though the person has not changed.
 Work setting:
You would have very frequently heard people say that their manager is different
during working hours and 1800 opposite while in a social setting.

18. Social setting:
The strength of the situational cues also affects social perception. Some situations
provide strong cues as to appropriate behaviour. In these situations, we assume
that the individual’s behaviour can be accounted for by the situation and that it may
not reflect the individual’s disposition. This is the discounting principle in social
perception.
For example, you may encounter an automobile salesperson who has a warm and
personable manner, asks you about your work and hobbies, and seems genuinely
interested in your taste in cars. Can you assume that this behaviour reflects the
salesperson’s personality? You probably cannot, because of the influence of the
situation. This person is trying to sell you a car, and in this particular situation, he
probably treats all customers in this manner.

19.  Kinds/Types of Perception:
We perceive objects in different manners as compared to their position in the
environment. Objects may be moving or static, when we have to perceive
motion.We may have to locate sounds and voices in the space around us.
1.Form Perception(Gestalt principles of perception)
2.Size Perception/ Perceptual Constancy
3.Motion Perception
4.Depth Perception
5.Time Perception
 Form Perception:
Our perception is a unified experience.We are familiar to organizing
things in our mind into a form, shape , a melody or a scene that makes
up a meaningful whole.

20.  Figure /Ground:
we see objects and forms of everyday experience as standing out from the background.
e.g., a clock hanging on the wall is perceived as the figure, while the wall is the ground
Our first perceptual decision is what is the image is the figure and what is the background
 Similarity:
The tendency to group together those elements that are similar in appearance
.objects similar in appearance are perceived as being part of same group.
 Proximity:
The tendency to group together those elements that are near to each other in
appearance group objects that are close together as being part of same group

21.  Closure:
The tendency to group according to enclosed or complete figures rather than
open or incomplete ones.we fill gaps in if we can recognize it.
 Simplicity:
The tendency to perceive a pattern in the most basic ,straightforward organized
manner.

22.  Perceptual Constancy:
Perceptual constancy is the tendency to perceive objects in a consistent manner despite
the changing sensations that are received by our senses. visual constancy plays an
important role in helping us adapt to our environment successfully. Learning plays an
important role in the development of constancy. Once we know that certain objects in our
environment have certain characteristics ,we tend to perceive them in the same way,
regardless of the conditions under which they are perceived.
 Perceptual Constancy:
Three types of constancy are explained briefly here:
1.Size Constancy
2.Shape Constancy
3.Color Constancy

23.  Size Constancy:
When we know that an object is of a certain size, we tend to perceive it as being that
same size, regardless of how far it is from our eyes. In Size constancy ,the perceiver
has the ability to judge true or measured size, regardless of the distance involved.
•E.g., when you finish a conversation with a friend and he begins to walk away ,the
image on retina become smaller & smaller.The knowledge that he is also farther
away, compensates for change in retinal image and you perceive him as the same size.
 Shape Constancy:
When we know that the object is a certain shape ,we tend to perceive it as the same
shape, regardless of the viewing angle.We have learned to make corrections in our
perception dependent on the angle from which we observe.
Everybody has seen a plate shaped in the form of a circle. When we see that same
plate from an angle, however, it looks more like an ellipse. Shape constancy allows
us to perceive that plate as still being a circle even though the angle from which we
view it appears to distort the shape.

24.  Color Constancy:
Colors of objects tend to remain constant in perception when we know their true
color refers to our ability to recognize that color remains the same regardless of how
it looks under different levels of light. That deep blue shirt you wore to the beach
suddenly looks black when you walk indoors.
 Depth perception:
Depth perception is your ability to see objects in three dimensions, including their
size and how far away they are from you. It’s made possible by lots of parts in your
eyes and your brain working together to process information, estimate their
location, and create the images you see.

25. Two types of cues that affect how we see things are:
• Monocular
• Binocular
 Monocular cues:
Monocular cues are the clues that allow us to see depth through
one eye. It works by judginghow big or small the object.
Example:When you see a plane fly by in the sky above you, it looks
really small. But you probably know that up close,a plane is hug
 Binocular cue:
Binocular depth cues are the images taken in by both eyes to give depth
perception or stereopsis. Binocular cues create a three-dimensional image of
the world one views.
Example: looking at an object in the distance and knowing how far away the
object is.There are two types of binocular depth cues:convergence retinal
disparity

26.  Motion perception
Motion perception refers to the brain ability to interpret and understand
movement in the visual field.
There are two types of motion perception:
• Real motion
• Apparent motion
 Real Motion:
The perception of the actual movement of the actual movement of objects in the
world is termed as real motion perception.
Example:Watching a ball being thrown and caught is a straightforward example of
real motion. As the ball moves through the air, your eyes track its path, registering its
changing position and trajectory.This tracking and perception of the ball's movement
showcase our ability to perceive real motion in the world around us.

27.  Apparent motion:
Apparent motion is an optical illusion in which a static image appears to be
moving due to the cognitive effects of interacting color contrasts, object shapes,
and position.It is also known as illusory motion or motion illusion.
E.g. In a movie, the illusion of continuous motion is created by displaying a rapid
sequence of still images.The movement of the moon across the night sky.
 Time Perception:
We take time in seconds, minutes and hours which pass into days, weeks, months ,
years and even centuries. Time is also perceived in terms of past, present and
future.It refers to the subjective experience of time, which is measured by
someone's own perception of the duration of the indefinite and continuous
unfolding of events. Another person's perception of time cannot be directly
experienced or understood, but it can be objectively studied and understood
through a number of scientific experiments.

28.  Laws of Perceptual Organization

29.  The Gestalt Laws of Perceptual Organization:
These are developed by German psychologists.The Gestalt laws describe "how
humans perceive the world around them through a psychological process known
as perceptual organization."
 Figure-Ground:
The first ofThe Gestalt Laws is known as the Figure- Ground relationship which states
that humans are able to visually separate objects on different layers of focus due to the
brain’s processing of negative space. In general, you’ll automatically perceive the larger,
lighter areas of an image as the background and the darker, lighter areas as the figure.

30. • For example:
Most humans will perceive the two faces in the left image and
the vase in the right image first. Interface designers will often
use this phenomenonin order to highlight focus points by
using semi-transparent overlays, shadows or by blurring the
elements in the background.

31.  Law of Proximity:
It refers to how close elements are to one another. Grouping subjects into a small area
will create the perception of grouping or, by putting white space between subjects, you
can create separation even when the other subject characteristics are the same. In the
image at the top of the page, the circles on the left appear to be part of one grouping
while those on the right appear to be part of another. Because the objects are close to
each other, we group them together.

32.  Law of Similarity:
Another way designers can create groupings is through the law of similarity.
This law states that subjects that have a similar visual appearance, including
their Colour , size and shape, will seem more related.You’ll probably see the
groupings of these colored circles as rows.

33.  Law of Symmetry:
One of the most common-knowledge Gestalt laws is that of symmetry. Humans
are instinctively attracted to symmetry as it creates the impression of stability
and order where as also simplifying the perception process of objects. A
symmetrical navigation menu. For example, tends to be better perceived than
an asymmetrical one.

34.  Law of Continuity:
The law of continuity holds that points that are connected by straight or curving lines are
seen in a way that follows the smoothest path. In other words, elements in a line or curve
seem more related to one another than those positioned randomly.When viewing a series
of lines, the human eye has a tendency to follow the smoothest path regardless of how
many lines there are. Any objects that reside along this path are intuitively viewed as being
related or grouped.

35.  Law of Closure:
According to the law of closure, we perceive elements as belonging to the same
group if they seem to complete some entity. Our brains often ignore contradictory
information and fill in gaps in information.You probably see the shape of a star
becauseyour brain fills in the missing gaps in order to create a meaningful image.

36.  Illusion:
Something that looks or seems different from what it is something that is false or
not real but that seems to be true or real.

37.  Type of Illusion:
There are two type of illusion:
IllusionOf motion.
The IllusionOf forms.

38.  Illusion of motion:
When a stationary stimulus is perceive as moving, it is named as illusion
of motion or movement.

39.  The Illusion of distance:
The illusion of distance occurs when the parallel lines to bend in different
directions.
 The Illusion of form:
Form perception is attained in relation to the figure and ground according
to the law of perceptionOrganization. As the figure is smaller then the
ground according to perceptual.

40.  Spiral circle illusion:
Psychologists have fail to understand this illusion. It seem that
the curving line behind the spiral have become the cause of
this illusion.The illusion is also known as the false spiral, or by
its original name, the twisted cord illusion.

41.  The Zollner Illusion:
The parallel lines seem to bend to each other instead of looking straight.
The reason of this Illusion is the smaller diagonal lines cutting the parallel
line.

42.  The Poggindorf's Illusion:
If two parallel line are dissected by another straight line separately, a large
straight line seem cutting the parallel line instead of two partial line.

43.  Herring's Illusion:
The Herring illusion can also be induced by a background of optic flow. It is two
horizontal line are cure by the line of different direction, will not look parallel.The
distance between the two lines looks greater where the lines assemble from
different direction as is found in fig

44.  The Illusion of size:
A near object is near usually perceived larger and farther object is perceived
smaller but in the moon illusion, moon is perceived larger on horizon where the
earth and sky seem to meet.

45. ThankYou