Perception involves both bottom-up and top-down processing. Bottom-up processing refers to perceptions being built from sensory input, while top-down processing refers to how our interpretations are influenced by knowledge and experiences. Sensory adaptation means we often don't perceive constant stimuli over long periods. Attention also plays a role, as we tune out unattended stimuli. Perception is the organization, identification and interpretation of sensory information to understand our environment. It is influenced by characteristics of the perceiver, perceived target, and situation.

1. Perception
By
Dr. S. Baranidharan
Dept. CS & AF

3. Perception is the organization, identification,
and interpretation of sensory information in
order to represent and understand the
presented information or environment.
Note: All perception involves signals that go
through the nervous system, which in turn
result from physical or chemical stimulation of
the sensory system.

5. Perception refers to the way sensory
information is organized, interpreted, and
consciously experienced. Perception involves
both bottom-up and top-down processing.

6. Bottom-up processing refers to the fact that
perceptions are built from sensory input.
On the other hand,
how we interpret those sensations is influenced
by our available knowledge, our experiences,
and our thoughts. This is called top-down
processing.

7. Although our perceptions are built from sensations, not
all sensations result in perception. In fact, we often
don’t perceive stimuli that remain relatively constant
over prolonged periods of time. This is known
as sensory adaptation.
Eg: Imagine entering a classroom with an old analog
clock. Upon first entering the room, you can hear the
ticking of the clock;
as you begin to engage in conversation with classmates or
listen to your professor greet the class, you are no
longer aware of the ticking.
The clock is still ticking, and that information is still
affecting sensory receptors of the auditory system.

8. There is another factor that affects sensation
and perception: attention. Attention plays a
significant role in determining what is sensed
versus what is perceived.
Eg: Imagine you are at a party full of music,
chatter, and laughter. You get involved in an
interesting conversation with a friend, and you
tune out all the background noise. If someone
interrupted you to ask what song had just
finished playing, you would probably be
unable to answer that question.

9. Keywords
• bottom-up processing: system in which
perceptions are built from sensory input
• inattentional blindness: failure to notice
something that is completely visible because of a
lack of attention
• perception: way that sensory information is
interpreted and consciously experienced
• top-down processing: interpretation of
sensations is influenced by available knowledge,
experiences, and thoughts

11. Features of Perception:
1. Intellectual process through which a person
selects the data from the environment,
organises it and obtains meaning from it.
• 2. Basic cognitive or psychological process.
Peoples actions, emotions, thoughts or
feelings are triggered by the perception of
their surroundings.
• 3. A subjective process.

13. Factors Influencing Perception:
• The factors which affects perceptual
mechanism are of three kinds:
• 1. Characteristics of the Perceiver
• 2. Characteristics of the Perceived or target,
and
• 3. Characteristic of the Situation

15. Characteristics of the Perceiver
(Internal Factors)
• Needs & Motives
• Self Concept
• Beliefs
• Past Experience
• Current Psychological State
• Expectations

16. Characteristics of the Perceived or
Target
• Size- The bigger is the size of the perceived stimulus, the
greater the possibility that it is perceived & vice versa.
• Intensity- More intense the external stimulus is, the more
likely it is to be perceived e.g. a loud sound, bright colour
etc.
• Frequency- The greater the frequency of repetition of
things, the greater will be the perceptual selectivity.
• Status- Perception is also influenced by the status of the
perceiver.
• Contrast – The stimulus which is in contrast with the sur-
rounding environment attracts more attention as compared
to the stimuli that blends in.

17. 3. Situational Factors:
• (i) Physical setting- This includes place, location, light,
heat, ventilation, basic amenities etc. If all these things
are proper then people may perceive positively and
vice versa.
• (ii) Social setting- This includes human resources i.e.
the people around you or the affected parties or the
people concerned about you or the persons you are
concerned about or the people who you work with.
• (iii) Organizational setting- This includes the hierarchy
in the organization, organizational setup, structure etc.
All these influence the perception.

19. Thank
You