2. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
Three Questions
1. Are there things that we perceive but are not aware
of, and can they affect our behavior?
2. How big or how unusual do objects have to be for
our senses to notice?
3. How much are the things we perceive influenced or
biased by our cultural, learning, emotional, and
personal experiences ?
These three questions are the key to understanding
how we perceive our world.
3. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
Sense and Perception
• Sense: tells something is there
• Perception: it tells us what it is
• Threshold: It is a limit on whether a stimulus can be
perceived or not. The threshold determines when we
become aware of a stimulus.
4. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTIONAL THRESHOLDS
• recognizing a stimulus
– Gustav Fechner
• defined the absolute threshold as the smallest
amount of stimulus energy (such as sound or light)
that can be observed or experienced.
– absolute threshold
• The intensity level of a stimulus such that a person
has a 50% chance of detecting it
5. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
p122 Threshold Graph
Absolute threshold: 50%
chance to hear the stimulus
Unconscious
stimulus: 0-
49% chance
of hearing
the stimulus increase in intensity
100%
chance to
hear the
stimulus
6. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTIONAL THRESHOLDS Continued
• The intensity of the unconscious stimulus has less
than 50% chance for the person to notice it.
• Example: Mammography reading-lowering threshold
• Accuracy issue: Radiologists' lack of experience
7. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTION THRESHOLDS (CONTINUED)
• EH Weber
– worked on the problem of how we evaluate whether a
stimulus such as loud music increases or decreases in
intensity
– Just noticable difference (JND): It refers to the smallest
increase or decrease in the intensity of a stimulus that a
person can perceive.
• Weber's law
– The increase in intensity of a stimulus required only to
make a noticeable difference increases in proportion to
the intensity of the initial stimulus.
8. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTION THRESHOLDS (CONTINUED)
• He found that when very low-intensity stimulants
were used – for example, when he asked them to
compare a 60 gram weight with a 90 gram weight –
the difference in people was easily detected.
• But when high-intensity stimuli were used, for
example, when asked to compare a 20-pound weight
with a 21-pound weight, he found that people could
no longer detect the difference.
9. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTION AGAINST SENSATİON
• Key Differences
– Sensation
• Our first awareness of stimuli
• External stimuli activate the sensory receptors
and these produce electrical signals that are
converted by the brain into meaningless bits of
information.
– Perception
• It is the experience we get after our brain
combines thousands of separate and
meaningless senses and turns them into a
meaningful pattern or image.
• Our perceptions are rarely exact copies of the
original stimulus.
• It is often altered, distorted, colored, or change by
our own unique experiences.
• Perceptions are personal interpretations of the
real world.
10. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTION AGAINST EMOTION (CONTINUED)
• Turning sensation into perception
1. Stimulant
• energy change in the medium, such as light waves,
sound waves, mechanical pressure, or chemicals
• Stimulants trigger the sensory receptors in our sense
organs.
2. Adaptation
• Light waves reaching the eyes focus on the retina,
where the light-sensitive photoreceptors are located.
• Light waves are absorbed by their photoreceptors and
converted from physical energy to electrical current, this
is called ADAPTATION.
• Electrical signals are converted into currents that are
sent to the brain.
11. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTION AGAINST EMOTION (CONTINUED)
3. Brain: Primary areas:
• Currents from the sense organs first go to different primary areas in
the brain .
4. Brain : Associative Fields
• Each sense sends its currents to different primary areas in the brain.
• currents are transformed into meaningless sensory particles such as
shape, color and texture.
• The "sense " currents are sent to the relevant association area in the
brain.
• meaningless particles into meaningful images called perceptions.
5. Personalized perceptions
• Each of us has personal experiences, emotions, and memories that
are automatically added to our perceptions by different parts of the
brain.
• As a result, our perceptions; they are a changed, distorted or even
distorted reflection of the real world.
• Perceptions are personalized interpretations rather than real
12. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES
• Structural versus Gestalt psychologists
– structuralists
• believed that you put together hundreds of
fundamental elements to form complex
perceptions
– Gestalts
• We believe that our brain follows a set of rules
that determine how individual items are
organized into a meaningful pattern or
perception.
• 'The whole , the parts from the total more is
more ''.
14. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
• organization rules
– organizational rules: determined by Gestalt
psychologists
• our brain determines how it combines and
organizes individual parts or elements into a
meaningful perception
15. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
figure-ground
• The most primitive feature of
perceptual regulation is to see the
focused object ahead of the others
and clearly . seeing visible objects
further back and more ambiguously
.
• to which we direct our attention
Things come forward more than
other objects , others stay in the
background. to which we direct our
attention and The object we see is
called the figure , and the objects
or parts in the background are
called the ground.
16. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
• innate ability to separate the figure
from the ground
• blind from a young age and in
adulthood people who have
regained their sight no ̧ without
working Distinguish between shape
and ground shown (Senden, 1960).
• • The figure-ground rule is for our
brain to organize stimuli as
perception . It is one of the first
rules he used ( Vecera , 2002).
17. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
Similarity
• we group similar-looking items together
18. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
– Completion
• We fill in the missing parts of a shape and see the shape as
complete
• Lack of sensory information review We tend to miss it and
perceive it as a whole when it does n't really exist .
• Best shape of parts to create we complete for Symmetry is
an important clue in this regard.
19. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
Proximity
• we group objects that are physically close
together
20. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
Simplicity
• stimuli are arranged
in the simplest
possible way
• It tells us that we
tend to view complex
shapes as a few
simpler shapes.
21. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ORGANIZATION RULES (CONTINUED)
continuity
• Prefer smooth or continuous paths when
interpreting a series of points or lines.
22. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
STABILITY IN PERCEPTION
• Object's perspective, illumination, proximity-distance
when it changes we tend to perceive that object as
relatively fixed and unchanging .
dimension constancy
• Perceiving that objects remain the same size
even as their images on the retina continually
grow and shrink
23. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
STABILITY IN PERCEPTION
shape constancy
• Perceiving an object as if it maintains the same
shape even though it constantly changes its
image on the retina when viewed from different
angles.
24. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
PERCEPTIVE STABILITY (CONTINUED)
brightness constancy
• Perception of brightness as
the same in changing
lighting
color constancy
• Perceiving colors as
remaining constant despite
differences in lighting
25. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH PERCEPTION
• Binoculars (two eyes) depth tips
– depth perception
• Although the images projected onto the retina
are only in two dimensions, height and width, it
refers to the ability of your eye and brain to add
a third dimension, depth, to all visual
perceptions.
• Depth perception cues fall into two large
classes:
– Binocular depth cues ( based on the
movement of both eyes)
– Monocular depth cues (connected to one
eye)
26. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH PERCEPTION
– Convergence
• stands for a binocular cue for depth perception
based on signals sent from the muscles that
turn the eyes
• To see near or oncoming objects, these
muscles turn our eyes inward, towards our
nose.
• The brain determines the distance of the object
using the signal sent from the muscles.
27. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH PERCEPTION
• retinal disparity:
– binocular depth cue based on the distance
between the eyes .
– Due to their different positions, each eye takes on
a slightly different image.
– The difference between the right eye and the left
eye is the retinal separation.
– The brain interprets a large retinal gap as near to
the object, and a small retinal gap as far away
from the object.
28. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
p129 RETINAL DIFFERENCE
1. The left eye
sees the fly
slightly
differently
2. The right eye
sees the fly
slightly
differently
3. The brain
creates depth
perception by
combining
images from the
right and left
eyes
29. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
Monocular depth tips
– produced by signals
from a single eye
linear perspective
• Distant
convergence of
parallel lines
resulting in
convergence
monocular depth
cue
30. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
Relative size
• monocular depth cue that occurs
when two objects are the same size
when we expect them to be the
same size .
• larger of the two objects appears
closer, and the smaller one appears
further away .
31. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
intervening
• objects top on top appearing when _ is a monocular
tip.
• upper object appears closer and the lower object
appears further away .
32. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
– light and shadow
• monocular depth cues where brightly lit objects
appear closer, while objects in shadows appear
farther away
33. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
– texture gradient
• Monocular depth
marking, in which
areas with sharp,
detailed texture are
interpreted as closer,
and areas with less
sharpness and weaker
detail are perceived as
farther
34. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
– atmospheric perspective
• monocular depth marking created by the
presence of dust, fog, clouds or water vapor
• We perceive clearer objects as closer and
more obscure objects as farther away.
35. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
DEPTH SENSE (CONTINUED)
– motion parallax
• (Parallax, Observer 's durus ̧ _ relative that occurs at
the location of an object, depending on change )
• • We perceive objects moving at high speed to be
closer to ourselves than objects that seem slower
and stationary .
• https :// isle.hanover.edu
/Ch07DepthSize/Ch07MotionParallaxExpl.html
36. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
ILLUSION
• strange perceptions
– Illusion
• a perceptual experience in which you perceive
an image to be so strangely distorted that it
cannot and does not exist in reality.
– impossible shape
• perceptual experience in which a drawing
appears to defy basic geometrical laws
37. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
p132 IMPOSSIBLE SHAPE
Does this impossible shape have
two ends or three?
42. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
Extrasensory PERCEPTION
• Definition
– a group of psychic experiences that involve
perceiving or sending information (images) outside
of normal sensory processes or channels
43. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
• four general abilities
• Telepathy: Sending one's own feelings and thoughts to
another the ability to send messages or read someone
else 's feelings and thoughts
• Intuition : Foreseeing future events .
• Hearing unseen voices, indirect clear vision ̧: Being aware
of an unknown object or event, the ability to perceive
events and objects outside the sensory field .
• Telekinesis: the mind 's power to influence matter , eg to
move objects without touching them.
44. Introduction to Psychology, 7th Edition, Rod Plotnik
Module 6: Perception
Extra-SENSIOUS PERCEPTION (CONTINUED)
• Prudence
– ability to detect events or objects out of sight
• psychokinesis
– the ability to apply the mind on matter; moving
objects
