Is a psychological process
which happens in our brain
during which the brain
makes sense of the visual
image detected by our eyes.
Retina
The light
sensitive
layer at
the back of
the eye.
Rods
A visual receptor that is sensitive to dim light
Cones
A visual
receptor that
is sensitive to
bright light
and colour.
Vision
Our eyes work by
detecting rays of light that
are reflected or emitted
by objects. This is a
biological process that
happens in our eyes.
Perceptual
Processes
The unconscious way
people interpret and
understand what
they see or notice.
The optic nerve
and the brain
What causes
the blind spot?
Blind Spot
The point in
the retina
where the
optic nerve
leaves the
eye, and as
there is no
room for rods
and cones, no
light is
detected.
The blind
spot contains
no rods and
no cones
Optic
chiasma
The cross - shape
where some of the
information from
the left and right
eye crosses over to
pass into the
opposite side of the
brain.
Visual
cortex
The area at
the back of
the brain
that
interprets
visual
information.
Seeing Depth
Depth cues
Monocular
One eye -
there are five
monocular
cues.
Size constancy
We perceive
an object as
the same size
even when its
distance from
us has changed.
Distant things
are scaled UP
Nearby
things are
scaled
DOWN
Relative size
Smaller
objects are
perceived
as further
away than
larger ones.
Texture gradient
When you look at
a scene, close up he
textured surface is
very detailed.
Further away it is
less clear.
height-in-the-plane
The objects at the bottom
of your field of view is
close to you. In the area at
the top of the field, the
objects are further away.
Superimposition
When one object is covering
another it tells us that the thing
you can see must be nearer
than the partly hidden object.
Linear perspective
Parallel lines appear to converge
(meet) in the distance
Binocular
Uses two eyes
to perceive
distance
Stereopsis
The greater the difference
between the view seen by the
left eye and the right eye, the
closer the viewer is looking.
The visual
'cues' that
we use to
understand
depth or
distance.
Gestalt Laws
'The whole is worth
more than the sum
of its parts'
Figure -
ground
A small, complex, symmetrical object
(the figure) is seen as separate from
a background (the ground)
Similarity
Figure sharing size, shape or colour are grouped
together with other things that look the same.
Proximity
Objects which are close together
are perceived to be related
Continuity
Straight lines, curves and shapes are
perceived to carry on being the same.
Closure
Lines or shapes are perceived as complete figures even if parts are missing.
Illusions
Visual
illusions
A conflict
between reality
and what we
perceive.
Fiction
Illusory
contour
An illusion caused
when a figure is
perceived even
though it is not
present in the
stimulus.
Colour
after-effects
An illusion
caused by
focusing on a
coloured
stimulus and
perceiving
opposite colours
immediately
afterwards.
Distortion
Where our
perception is
deceived by
some aspect
of the
stimulus.
This can
affect the
shape or
size of an
object.
Ambiguous
figure
A stimulus with
two possible
interpretations, in
which it is possible
to perceive any one
of the alternatives
at any time.
Gestalt theory of illusions
Muller-Lyer
Closure
This works with circles as well
as fins. This suggests that in
perceiving the figure as whole,
we tend to 'add' the fins/circles
to the central lines. This can pull
the shape together, so it looks
smaller, or (if it extends beyond
the central line) stretches it out
and makes it look longer.
Kanizsa
triangle
Fiction
Closure
Our perception makes a 'whole'
shape using closure. We complete
the edges to make a familiar
shape (a triangle). This is the
'figure' of the figure-ground
relationship.
Rubin's Vase
Ambiguous Figure
Figure -
ground
When we identify a 'figure', it is
separate from the 'ground'.
Normally any part of the image
cannot be both; it can only be figure
or ground. If we encounter a
situation where something could be
either figure or ground, it becomes
ambiguous so we see an illusion.
Experiments and design
Descriptive
statistics
Mode
An
average
that is
the most
common
score or
response
in a set
Mean
An average that is
calculated by
adding up all the
scores in a set and
dividing by the
number of scores
Bar
chart
A graph with separate bars.
Usually there is one bar for each
condition in an experiment
Median
An average that is
the middle number
in an ordered set of
data
Range
Shows the spread of a set of
data by looking at the biggest
and smallest scores
Ways to summarise results
from a study. They can
show a typical average
score of how spread out
the results are.
IV
The factor
which is
changed by the
researcher in
an experiment
to make two or
more
conditions
DV
The factor
which is
measured in
an experiment
Experimental
(Participant)
design
Independent
groups
design
Different
participants
are used in
different
conditions in
each
experiment..
Repeated measures
design
The same
participants are
used in all the
conditions in an
experiment
Hypothesis
A testable
statement
of the
difference
between
the
conditions
of an
experiment.
It describes
how the IV
will affect
the DV
Controls
Ways to
keep
variables
constant
in all
conditions
Palmer (1975): Schemas
and perception
Schemas
We have a
framework of
knowledge
about
objects/people
that affects our
perception of
information
and memories.
Perceptual
set
The tendency to notice some things more than others.
This can be caused by experience, context or expectations.
Reconstructive
memory
Recalled material is not just a 'ccpy'. Information is stored
and when it is remembered it is 'rebuilt', so can be affected
by extra information and schemas we might already have.
AIM
To find out
whether
context
would affect
perception
PROCEDURE
64 Students
tested in a
laboratory
experiment
were shown
visual scenes
like a kitchen
for 2 seconds
(to provide
context)
Appropriate
Inapproproate
Inappropriate,
different object
No context
RESULTS
The participants correctly
identified the most objects after
seeing an appropriate context
(82%) and the least after seeing
an inappropriate context (40%)
CONCLUSION
Expectations affect perception.
People have a perceptual ser based
on context which affects how
accurately they recognise objects.
EVALUATION
Strengths
Controlled how
long participants
saw the object for.
Clear instructions
so they knew
exactly what to do.
Weaknesses
As some data
couldn't be used,
there were
fewer results
The participants were
told what they would
be doing, this may
have caused them to
try harder.
Bartlett
(1932):
Schemas and
remembering
stories
Serial Reproduction
A task where a piece of information
is passed from one paticipant o te
next in a chain or 'series'
Repeated
Reproduction
A task where the participant is given a
story or picture to remember. They then
recall it several times after time delays.
AIM
To investigate how
information changes with
each reproduction and to
find out why it changes.
PROCEDURE
All participants read 'The War
of the Ghosts' (deliberately
unfamiliar story).
RESULTS
Form
Once a story has a
particular outline it
sticks. eg. the
order of events
Details
Information such as
names & numbers are
lost. If remembered they
become stereotyped.
Simplification
Events are made less complex.
This can change the meaning.
Addition
Inaccurate details are
added to the story.
CONCLUSION
Unfamiliar material changes when it is
recalled. It becomes shorter, simpler
and more stereotyped. This may be due
to the effect of schemas on memory.
Strengths
Both tests were
repeated to
show patterns
Other stories
used were not
individual
Weaknesses
By using unfamiliar
material, he could not
be sure the changes
would always occur
Not always
retested
over the
same time
gaps, so
could not be
compared
fairly.