perspective and perception

1. SENSATION AND
PERCEPTION

2. • Sensation: is stimulation of sensory receptors and
transmission of sensory information to the central nervous
system. E.g
Feel the wind on your face or hear a car horn honking in the
distance.
• Perception: is process by which sensations are organized
and interpreted to form an inner representation of the world.
E.g One person may perceive a dog jumping on them as a
threat, while another person may perceive this action as the
pup just being excited to see them

3. Absolute threshold
▫ absolute threshold – the minimal amount of
energy that can produce a sensation
• Absolute threshold is the smallest level of
energy required by an external stimulus to be
detectable by the human senses, including
vision, hearing, taste, smell and touch.
• It is more precisely defined as the degree of
intensity of a stimulus necessary to correctly
detect that stimulus 50% of the time.

4. Sensory Adaptation
• Sensitization:
Positive adaptation – Process by which we
become more sensitive to stimuli of low
magnitude e.g
repetition of a painful stimulus may make one
more responsive to a loud noise.
• Desensitization:
Negative adaptation – Process by which we
become less sensitive to stimuli that remains
the same e.g
A very common phobia is the fear of flying.

5. Perceptual Organization
• Perceptual organization refers to the way
information is received by our senses and
interpreted to make it meaningful.
• Figure-Ground Organization:
Inborn part of a stimulus stands out as a figure
(object) against a less prominent background (ground)
• Reversible Figure:
When figure and ground that can be reversed
▫ Ambiguous, unstable figures

6. Gestalt Rules for Perceptual
Organization
• Proximity
– Nearness of objects; the perceptual tendency to
group together objects that are near one another
• Similarity
– Similarity of objects; the perceptual tendency to
group together objects that are similar in
appearance
• Continuity
– Series of points having unity; the tendency to
perceive a series of points or lines as having unity

7. • Common Fate
– Elements moving together are grouped
together
• Closure
– Perception of a complete figure, even when
there are gaps in sensory information

8. Examples of Gestalt Principles

9. Perception of Motion
• Visual perception of motion is based on
change of position relative to other objects
– Stroboscopic motion: a visual illusion in which
the perception of motion is generated by a series
of stationary images that are presented in rapid
succession
Depth perception is your ability to see
objects in three dimensions, including their
size and how far away they are from you.

10. • Relative size refers to the fact that the more
distant an object, the smaller its image will
be on the retina
• Interposition is a type in which one object
partially covers another object, giving the
perception the object that is partially
covered is farther away.

11. • Linear perspective is defined as a type of depth
prompt that the human eye perceives when
viewing two parallel lines that appear to meet at a
distance.
Location of pic in Plane
Appears Closer: Below the horizon
Appears Farther Away: Above the
horizon

12. BINOCULAR QUES
• Cues require use of both eyes
• Appears Closer: Eyes feel tug inward toward
nose
• Appears Farther Away: Eyes relax outward
toward ears
• Binocular disparity:
• Appears Closer: Huge discrepancy between
image seen by left eye and image seen by right
eye
• Appears Farther Away: Minuscule discrepancy
between image seen by left eye and image seen
by right eye

13. • Perceptual Constancies
• Perceptual constancy occurs when our
perception of an object remains the same even
when our proximal sensation of the distal object
changes (Gillam, 2000).
• Size Constancy
• Shape Constancy
• Color Constancy