did you know?

chapter 6>>
visual perception
POSSIBLY THE BEST ILLUSTRATION OF THE WAY BODY AND MIND
INTERACT TO ENABLE US TO PERCEIVE THE WORLD AROUND US IS IN
THE PROCESS OF VISION. OUR EYES RECEIVE THE STIMULUS ENERGY
OF LIGHT, REFLECTED FROM AN OBJECT IN THE OUTSIDE WORLD,
LIGHT-SENSITIVE CELLS IN THE EYE SEND MESSAGES TO THE BRAIN
AND THEN WE INTERPRET AND UNDERSTAND WHAT WE SEE.

six stages of visual perception
>>key knowledge>>
Application of psychological perspectives to explain
visual perception:
> characteristics of the visual perceptual system and
the visual processes involved in detecting and
interpreting visual stimuli
> the effect of psychological factors on perceptual set
> distortions of visual perceptions by illusions.
(VCE Study Design 2009)
A study of the way in which we perceive the world around
us through the sense of vision is a wonderful example of the
way the brain and body work together, depend on each other
and help each other as we go about our everyday activities.
One of the key objectives of this chapter is to help
you to understand how the physical reality of light from
the object in the environment—referred to as the distal
stimulus—is cast as an image on the retina—called the
proximal stimulus—and nerve impulses travel to the brain
where higher mental processes enable us to organise and
interpret what we see.
fig 6.1>> The eye
>>chapter overview>>
Six stages
of visual
perception
The processes
of visual
perception
The principles
of visual
perception
Distortions of
perception
> Reception
> Transduction
> Transmission
> Selection
> Organisation
> Interpretation
Reception and light energy
Reception and absolute threshold
The role of the eye in visual perception
Selection and organisation of visual
stimuli
> Perceptual constancies
> Size constancy
> Shape constancy
Gestalt principles of perceptual
organisation
> The phi phenomenon
> Figure-ground organisation
> Camouflage
> Closure
> Similarity
> Proximity
Depth perception
> Binocular depth cues
> Retinal disparity
> Convergence
> Monocular depth cues
> Accommodation
> Pictorial depth cues
> Linear perspective
> Interposition
> Texture gradient
> Relative size
> Height in the visual field
The effect of psychological factors on
perceptual set
The Ponzo Illusion
The Müller-Lyer Illusion
> The carpentered world hypothesis
> The perceptual compromise
theory
The Ames Room Illusion
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chapter 6>> visual perception
The actual image on our retina is:
> upside-down
> back-to-front
> blurred
> crisscrossed by a network of veins
> patched by holes.
Yet when this image has been sent to the brain, it
is processed so that we see a crystal-clear picture! The
process itself—from receiving an image to ultimately
interpreting what we see—is complex and has been studied
extensively by a number of psychological perspectives as
discussed in Chapter 5.
The processes involved in sensation and perception
are also thought to be adaptive. From an evolutionary
perspective, the ability to see, hear, touch, smell and
taste has developed over thousands of years and through
millions of changes—leaving our senses perfectly suited
to our environment and to help us survive and reproduce
(Tooby & Cosmides 1992, cited in Westen et al. 2009). Just
like frogs, which have an inbuilt ‘bug-detecting’ function
in their visual system designed to activate when a tasty
insect is in view, humans have specialised areas in the brain
that allow the perception of faces and facial expression.
This can be seen in infants, who have an innate or inborn
tendency to show greater interest in objects that look like a
human face (Adophs, Damasio, Tranel & Damasio 1996).
The eye is a fantastic organ—it is very complex in
construction, but we only need to know about a few of its
structures.
fig 6.2>> Movement of light entering eye
112
From the time we receive an image to when we can
identify what we see, six stages have been identified, some
of which occur at about the same time. Essentially these
six stages progress, in sequence, from being reflexive
physical functions of the eye and nervous system to being
psychological functions of the brain, involving memory
and thought processes.
sensation and
perception
1 Reception: Light enters the eye through the cornea,
a tough transparent tissue covering the front of the
eye. It then passes through the pupil—the hole in
the middle of the coloured part of the eye (the iris).
The lens then focuses the light on the retina, which
contains the photoreceptors—light-sensitive cells called
rods and cones.
2 Transduction: The electro-magnetic energy that we
know as light energy is converted by the rods and cones
into electro-chemical nerve impulses. This allows the
visual information to travel along the fibres of the optic
nerve to the brain.
3 Transmission: The next task for the rods and cones
is to send the nerve impulses along the optic nerve to
the primary visual cortex in the occipital lobes, at the
very back of the brain where specialised receptor cells
respond as the process of visual perception continues.

fig 6.3>> The brain makes sense of what we see.
4 Selection: We can’t possibly pay attention to all the
millions of stimuli that enter the eye at the same time,
so we pick out the ones that are important to us and
pay attention to those. At this stage of the process, the
image is broken up by specialised cells called feature
detectors. Feature detectors are cells that individually
respond to lines of a certain length, lines at a certain
angle or lines moving in a certain direction. Feature
detector cells are found in the optic nerve and in the
primary visual cortex.
5 Organisation: When visual information reaches the
brain (visual cortex), it is reorganised so that we can
make sense of it. We do this by using certain visual
perceptual principles:
> perceptual constancies
> Gestalt principles
> depth and distance cues
These are explained in the next section of this
chapter.
Once the image is reassembled using these principles,
it travels along two pathways simultaneously: to the
temporal lobe, to identify the object, and to the parietal
lobe, to judge where the object is in space (in relation to
our visual field and ourselves).
6 Interpretation: This is the process whereby the visual
stimulus/object is given meaning. The temporal lobes
identify what the object is by comparing incoming
information with information already stored in memory.
Past experience, motives, values and context help us
understand what we are looking at by contributing to
our perceptual set (as discussed later in this chapter).
At the same time as information is sent to the temporal
fig 6.4>> Do you know why a person cannot see clearly
underwater? The cornea of the eye is designed to refract or bend
light rays travelling through the air—not through water. So when
you put on swimming goggles or a diving mask, the layer of air
between the water and cornea allows you to see more clearly.
lobes, it also travels to the parietal lobes, which assist in
judging where the object is in space (in relation to our
visual field and us).
Patients who have damage or tumours in parts of
the temporal lobe responsible for identifying a visual
stimulus may be unable to recognise an object or a
familiar face (prosopagnosia). Patients who have damage
to the parietal lobe will be able to recognise an object but
may constantly bump into furniture or misjudge picking
up their knife and fork.
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chapter 6>> visual perception
Wavelength in
nanometres
Wavelength in
metres
review 6.1
Copy this table into your workbook or use a computer. Complete the table using the information
provided for each stage of the visual perception process. (Note that the image prior to entering
the eye during the reception stage is the correct way up but by the time it reaches the retina, it has
been turned upside down and back to front.)
Gamma
rays
Reception Transduction Transmission Selection Organisation Interpretation
the processes of visual
perception
reception and light energy
The process of light entering the eye is an important part of our ability to receive and interpret
a visual stimulus. However, before the eye can receive the visual stimulus, there are a couple of
elements that must be in place.
First, the light energy must be within the visible part of the electromagnetic spectrum.
Wavelengths of between 360 and 760 nanometres form the visible spectrum (1nm = 1 billionth
of a metre). The energy that enables us to see is what we call light energy, the visible part of the
electromagnetic spectrum.
400 500 600 700
The Visible Spectrum
Ultra-
Infrared
X-rays violet
Radar
rays
rays
Wavelength in nanometres
400 500 600 700
Perceived colour
FM Television
Short
wave
Radio waves
Broadcast
bands
10 – 12 10 – 10 10 – 8 10 – 6 10 – 4 10 – 2 102 1 104 106 fig 6.5>> Electromagnetic spectrum, including the visible spectrum
114
Violet
Indigo
Blue
Green
Yellow
Orange
Red
AC circuits

eception and absolute
threshold
The second important element in the eye detecting the light stimulus is that
the light energy that falls within the visible light spectrum must be intense
enough for the human eye to see. In other words, it must reach absolute
threshold. The absolute threshold is the minimum amount of light energy
needed for an observer to perceive a stimulus, in ideal conditions, 50 per cent
of the time.
One method psychologists use to measure absolute threshold is by
presenting light stimuli at different intensities to see what level of intensity
is needed for a person to detect the light. If that person detects it during the
experiment about 50 per cent of the time at a particular intensity (the point
at which they actually perceive it), then absolute threshold has been reached.
Absolute threshold for the senses are:
> Hearing: ticking of a watch six metres away.
> Smell: one drop of perfume in a large house.
> Taste: one teaspoon of sugar dissolved in 10 litres of water.
> Touch: the wing of a fly falling on the cheek from a height
of one centimetre.
> Vision: the flame of a candle 50 kilometres away on a dark, clear night.
These are based on sound scientific research but may not be the same for
everyone and can vary depending on a range of environmental factors (noise,
amount of light) and psychological factors (fatigue, motivation, stress,
expectations). For example, if a person has had someone break into their
house, they will be more highly attuned to sounds at night, and this may
affect their usual absolute threshold for sound.
the role of the eye in visual
perception
As already mentioned, light enters the eye through the cornea, a tough
transparent tissue covering the front of the eye. It then passes through the
pupil, the hole in the middle of the iris. The lens then focuses the light onto
the retina, which contains photoreceptors (light-sensitive cells).
The retina is nerve tissue that covers more than 50 per cent of the
inner surface of the back of the eye. The retina contains two types of
photoreceptors: rods and cones.
Rods: There are 125 000 000 in each eye.
> They are responsible for vision in low light (that is, they are very
sensitive to light).
> They are responsible for peripheral vision (out of the corner of the eye).
They are concentrated at the edges of the retina.
> They have low visual acuity (they can’t register detail).
> They can register only in black and white.
> They are most sensitive to light of approximately 500 nm wavelength.
fig 6.6>> Your eyes can detect a
candle flame up to 50 km away on a
clear dark night.
fig 6.7>> Your tastebuds can detect one
teaspoon of sugar in 10 litres of water.
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chapter 6>> visual perception
fig 6.8>> Structure of the retina
Cones: There are 6 500 000 in each eye.
> They are concentrated in the middle of the retina.
> They are responsible for vision of detail.
> They are responsible for colour vision (and black-andwhite
vision in daylight).
> They require high levels of light to enable them to respond.
did you know? Psychologists have
learnt a great deal about our vision through
experimentation on animals. They discovered how
receptive fields in ganglion cells respond to an image
after it has been transduced (converted to nerve
impulses) by inserting a tiny electrode into the
brain or retina of an animal. By holding the animal’s
head still and flashing light to different sections of
the visual field, they were able to identify and map
the receptive fields of ganglion cells of the retina
(Westen et al. 2009).
116
review 6.2
1 What is the range of the visible light spectrum in
nanometres?
2 Draw a visible light spectrum in colour and show where
ultraviolet and infrared rays are situated.
3 Explain what happens in transduction.
4 In a table, write down the characteristics for rods and
cones (number, whether they are for daytime vision
and so on).
5 You have soccer practice after school during winter
and your coach wants you to play till it’s almost dark.
Which photoreceptor is better suited to low light
conditions?
6 Grandma is busy knitting you a pair of woollen socks.
She is sitting in her lounge with her spectacles and a
bright light. She needs to focus on what she’s doing.
Which photoreceptors are best suited to activities that
require clear vision in bright light?

the principles of
visual perception
selection and
organisation of visual
stimuli
At any given moment, vast amounts of visual stimuli enter
the eye—far more than we can pay attention to. The brain
selects and organises visual information according to a
number of visual perceptual principles.
Perceptual constancies
Perceptual constancies enable us to maintain a stable
perception of a stimulus although the image on the retina
may change (e.g. in size or shape). The more familiar we
are with the observed object, the more likely it is that
we will maintain perceptual constancy of it. Perceptual
constancies are usually learnt early in childhood.
Size constancy
This term refers to the fact that we maintain a constant
perception of an object’s size even though the size of the
image on the retina alters as the object moves nearer to
or further from us. For example, when we look at a friend
from a distance of five metres, he produces a retinal
image twice the size of the one he produces when he is ten
metres away. Because we are familiar with his height we
don’t change our perception of it, but we use the size of
the image as a cue to provide information about how far
away he is.
Shape constancy
An object is perceived to maintain its known shape despite
the changing perspective from which it is observed. This
is a learnt skill—a toddler may have difficulty perceiving a
familiar toy if it is viewed from an unusual angle. Objects
that are familiar to us can be accurately interpreted when
viewed from any direction. For example, as a door opens,
its retinal image changes shape from a rectangle to a
trapezium, but we easily maintain our perception of a
rectangular door.
gestalt principles
of perceptual
organisation
Gestalt is a German word that means ‘good form’. Gestalt
psychology developed early in the twentieth century and
is based on the principle that ‘the whole is greater than
the sum of its parts’. In terms of sight, it deals with the
tendency for our visual system to perceive what we see as a
meaningful whole.
How can this be? This answer is described in the
Gestalt principles of visual perception.
The phi phenomenon
Although less common than they used to be, you can still
find some local stores—often ‘Fish and Chip’ shops—with
a line of light bulbs round the outside of the window. At
night these bulbs light up one at a time, and as you watch
it looks as if one light is running around the window. It’s
not doing that, of course, but the property of motion is
present in the whole, rather than in any of the individual
parts (the light globes).
fig 6.9>> Size constancy—the person casts a larger image on
the retina as he moves closer, but we know he remains the same
size, so we use the information to establish his distance from us.
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chapter 6>> visual perception
did you know?
Animals such as leopards need to
hide in trees so they can surprise
their prey. Thinking about the
principle of figure-ground,
complete this sentence:
‘The leopard’s black spots on
its yellow fur mean that when
it is in a tree its is
broken up, it no longer stands
out as a against the
fig 6.11>> Can you see the soldier in
camouflage? The contour is broken up
to enable the figure to blend with the
background.
of the leaves and
speckles of sunlight, and as long
as it remains still it will be very
hard for other animals to see.’
118
fig 6.10>> Rubin’s vase. Figure-ground—a special case. This figure may be seen as either
a vase against a dark background or two faces in profile, depending on which is chosen as
figure and which is chosen as the ground.
This can also be seen outside Crown Casino in Melbourne, where lights
look like bubbles flowing out of the top of a champagne bottle.
This effect is known as the phi phenomenon. Have you seen it
anywhere else? Of course you have! It is the principle that makes cartoons,
movies and television work. One still picture after another gives us the
impression of movement on the screen.
Figure-ground organisation
The first Gestalt principle of visual perception that develops in infants is
figure-ground organisation. The part of the visual field being attended
to and focused on is the figure and its surroundings are the ground. Figure
and ground are separated by an imagined contour (line). The contour
is ‘owned’ by the figure. In children’s drawings, we often see a black line
around a figure emphasising the separation of figure and ground.
Camouflage is where the Gestalt principle of figure-ground is used to
‘blend’ the contour of the figure (which usually stands out) against the
ground (background), making it more difficult to see. We not only see
camouflage in nature, with leopards, tigers and giraffes; the army uses
camouflage uniforms to enable soldiers to blend in to their surroundings
and avoid detection.
Closure
Closure is when we perceive an object as being whole despite its actually
being incomplete. Many company logos use such incomplete figures in
their designs.

Similarity
Similarity is when the individual parts of a stimulus
pattern are similar (e.g. in size, shape or colour).
We tend to group them together as a meaningful
‘whole’—a single unit.
A
X X X X X
O O O O O
X X X X X
O O O O O
We tend to perceive rows of ‘X’ and ‘O’ in group A
and columns of ‘X’ and ‘O’ in group B.
Proximity
When the individual parts of a stimulus pattern are
close to each other, we tend to group them together as
a meaningful ‘whole’—a single unit.
A
X X X X X
X X X X X
X X X X X
depth perception
B
X X X X X X X
X X X X X X X
X X X X X X X
The point made above about Gestalt principles also
holds for depth cues: there are many other depth cues
besides those listed below. These examples show us
how depth and distance are perceived.
Depth and distance cues are vital to us. This is
because we exist in a three-dimensional world but
have only two-dimensional images on our two retinas
from which to judge depth and distance.
Depth cues may be binocular (using both eyes) or
monocular (using one eye alone or both
eyes together).
B
X O X O X
X O X O X
X O X O X
X O X O X
You can choose how to perceive a group of shapes
(as rows or columns) but tend to perceive the ones
on the right as rows, not columns.
> Many other Gestalt principles of visual
perception exist but these examples show how
they work.
fig 6.12>> Cartoonists use the principle of closure when they
draw characters with little detail.
6.1 investigate
1 Make your own animation!
> You will need three sheets of A4 paper cut
into 12 equal rectangles. This will give you a
total of 36 pages for your animation.
> Place the 36 pieces together to create a
small booklet and secure one end with a clip
or staple.
> Draw a stick figure of your choice on each
sheet, with each figure slightly different.
Think of each piece of paper as the different
frame of a cartoon or movie.
> Once you have drawn a progression of
pictures on the 36 pages, hold the secure
end
and flick through to watch your animation
come to life. You have just created your own
phi phenomenon!
2 Use of Gestalt principles
Look through magazines, newspapers and the
Yellow Pages. How many company logos can you
find where one or more Gestalt principles is used
in a clever way in the design? Make a table of
your findings using these headings: ‘Company’,
‘Logo’, ‘Gestalt principle used’.
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chapter 6>> visual perception
Binocular depth cues
Retinal disparity
Retinal disparity is a cue that comes about because our
eyes are set about 6–7 centimetres apart. When an object
is within about 20 metres of a viewer (with the strongest
depth cue occurring within 7 metres), each eye receives a
slightly different image on the retina, resulting from the
different angles of view from each eye to the object being
observed. The brain fuses these two images together in
stereoscopic vision. The more different the two images,
the closer the object will be to the viewer.
Try this yourself:
> Hold a pen at arm’s length and look past it at the other
side of the room.
> Close one eye and then the other and watch how far the
pen ‘jumps’ from side to side.
> Now bring the pen closer—about 40 cm from your
eyes—and repeat the process. What do you notice?
The process of retinal disparity is artificially recreated in
‘magic eye’ pictures from two flat, two-dimensional patterns
fig 6.13>> Magic eye picture—what can you see?
120
viewed from about 20 centimetres. Each eye observes a
slightly different view of the same scene and the brain fuses
the two images together in the same way it would when
observing a real (three-dimensional) scene.
If you can look ‘through’ the picture below, you will see
a ‘three-dimensional’ star in the middle of it.
Convergence
Convergence is also a binocular depth cue. As an object
comes closer to us, the eyes turn inwards to keep the
object centred on the retina. This cue, again, operates
for objects within about seven metres. The brain reads
the amount of turning from the tension of the muscles
that move the eyes and uses this to make judgments of
distance. The more the turning, the closer the object is to
the viewer. Try this yourself:
> Hold your pen vertically at arm’s length and slowly
bring it closer to your nose, watching it with both eyes
all the time.
> As the pen gets close to your nose, you can feel your
eyes turning and soon you go ‘cross-eyed’.
© 2009 Magic Eye Inc.

Monocular depth cues
Two types of monocular depth cues enable us to judge
depth and distance using one eye: accommodation
(a monocular cue) and pictorial cues.
Accommodation
Accommodation involves the lens of the eye (located
behind the iris) changing shape so that it can focus light
rays onto the retina. Small muscles called ciliary muscles
control whether the lens bulges (for closer objects) or
flattens (for more distant objects). At the same time, the
tension in the ciliary muscles is received by the brain
to confirm the location of the object being viewed. The
greater the tension, the closer the object.
Try this yourself. Take a pen and close one eye. Move
the pen as close to you as you can whilest maintaining
focus. You should be able to focus on a close object
(between 8 and 10 cm away—depending on your eyesight).
Keep focusing on the pen until you feel the tension within
your eye. That’s your ciliary muscles at work keeping your
brain informed.
Pictorial depth cues
Pictorial depth cues are named ‘pictorial’ because they are
used by artists to create a three-dimensional perception of
something that exists on a two-dimensional surface.
> Linear perspective (first described by Leonardo da
Vinci) is one of the most basic skills an artist uses
to create apparent depth. Parallel lines are made
to converge as they extend along the page to an
imaginary point (where in theory they meet) at the
horizon, as shown in Figure 6.14.
> Interposition (overlap) is based on the partial
blocking or obscuring of one object by another.
The obscured object appears to be further away
than the object obscuring (overlapping) it. This
is an effective cue for determining which objects
are closer than others, but it is not as effective for
actually judging distance.
> Texture gradient is used to make surfaces in a
picture appear to recede into the distance. Artists
draw less and less detail as a surface is more and more
distant, the same way we see it in real life. This is
shown in the boardwalk at Rhyll, Phillip Island. In the
foreground we can see every detail of the wood and
the mesh, but as the boardwalk gets further away it
becomes much less detailed (Figure 6.15).
fig 6.14>> Linear perspective shows parallel lines converging in
the distance.
fig 6.15>> Rhyll boardwalk
> Relative size is a pictorial depth cue based on our
tendency to perceive the object producing the largest
retinal image as being the nearest, and the object
producing the smallest retinal image as being the
farthest. For this cue it is necessary to know the real
size of the objects so that accurate comparisons can
be made. Think about watching a game of football
from behind your team’s goal—you realise that the
players at the opposite goal are far away; you don’t
think they are tiny!
> Height in the visual field is a pictorial depth cue
that shows depth by portraying objects further away
as being closer to the horizon. In a picture, objects in
the sky, such as aeroplanes, clouds and birds, will be
perceived as further away as they become lower in the
visual field (closer to the horizon). On the other hand,
trees, houses and people (objects on the ground) will be
perceived as further away as they become higher in the
visual field (closer to the horizon).
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chapter 6>> visual perception
fig 6.16>> Which of these animals is being hunted by the
warrior?
6.2 investigate
122
because of what we have seen in the past.
You be the artist
1 Draw a picture using the following pictorial depth
cues. (Alternatively, find a picture on the Internet
and use that instead.) Label your picture with the
pictorial cues, making sure that you explain each
one to illustrate your understanding.
> linear perspective
> overlap/interposition
> texture gradient
> relative size
> height in the visual field.
2 What is the key difference between monocular
and binocular depth cues?
3 Why do we receive a slightly different image on
each retina?
4 Create a poem or a song using monocular and
binocular depth cues. Make sure that each
term is either defined or explained in some way
and that your poem/song makes sense. Tune
suggestions:
> School anthem
> Mary had a little lamb
> Itsy bitsy spider
> Come up with one of your own!
> Present your creation to the class!
A picture similar to Figure 6.16 was used by
researchers to discover that members of some African
tribes did not use the last two cues to estimate depth
and distance. The Africans were very surprised at what
they thought was a picture of a hunter attempting to
spear a very small rhinoceros!
> We know that a rhino is much bigger than a zebra,
so we apply our knowledge to judge that the zebra
is much closer to us—at about the same distance as
the hunter.
> We would apply the depth cue of ‘height in the
visual field’ to judge that the hunter is about to
spear the zebra, not the rhinoceros, which is in the
distance.
Cross-cultural research has allowed psychologists
to understand that even though every human being
with normal vision receives exactly the same visual
information, our individual and cultural experiences
can influence our interpretation of what we see
the effect of
psychological factors
on perceptual set
Expectations that are created by our previous
experiences, the environment in which a stimulus is
seen, our motivation and even our emotional state can
combine to predispose us to perceive the world in a
certain way.
Perceptual set:
Perceptual set is:
1 A predisposition to perceive stimuli in a specific way,
i.e. interpreting what we see according to certain
preconceptions (interpretation).
2 A predisposition to attend to only certain features or
aspects of our field of view (selection).
Several factors can influence perceptual set,
including:
Previous experience: Previous experience can affect
visual perception, especially if the experience holds
significant personal meaning. The same stimulus can
be interpreted differently by different people.
Context: Context sometimes has an immediate effect
on our expectations. Context refers to the environment
in which a perceived stimulus is observed.

PREVIOUS EXPERIENCE
MOTIVATION
EMOTION
CONTEXT
fig 6.17>> Factors affecting our perceptual set
Motivation: Very often we see what we want to see. On a long drive in the
country, running low on petrol, a sign that reads ‘FOOD AHEAD’ may well
be interpreted as ‘FUEL AHEAD’.
Emotion: We could interpret someone’s facial expression as showing
laughter or crying, depending on how we are feeling ourselves.
fig 6.18>> Quickly look at this illustration. Close your eyes and recall what you saw.
did you know? Researchers found that when they
presented a picture of a farmyard to a group of subjects and then
asked them to describe it from memory, they were able to do so
quite well. However, when shown the picture above, the subjects
were surprised by the picture of a giant squid outside the barn—it
is out of context, so they concentrated on this and failed to pay
attention to the other items in the picture.
PERCEPTUAL SET
Bugelski & Alampay (1961) performed the very famous rat-man experiment.
One group of participants was shown a series of line-drawings of faces and
then the ambiguous rat-man stimulus—the majority identified it as an old
man. The other group was shown a series of line-drawings of animals and
then the ambiguous stimulus—the majority identified it as a rat or mouse.
This shows how the perceptual set, created by prior experience, influences
perception.
fig 6.19>> Rat-man. Can you see the rat
and the man?
SELECTION
INTERPRETATION
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chapter 6>> visual perception
review 6.3
1 Describe how the brain uses certain principles to
organise visual information.
2 What theory underlies all of the Gestalt principles?
3 Explain the phi phenomenon using local examples.
4 What is figure-ground organisation? Why is a
‘contour’ important to this principle?
5 Why do we find it so difficult to see animals
camouflaged in their environment?
6 Explain how ‘closure’ works.
7 Give an example of similarity and explain why the
example is seen as a single unit.
6.3 investigate
124
Try the rat-man experiment
1 Trace the drawings below onto pieces of card or paper.
8 What is retinal disparity and why is it important to
depth perception?
9 Convergence is also a binocular depth cue. Explain
how this works.
10 Why are depth cues so important to us?
11 What techniques have been developed by artists to
show visual representations of three dimensions on a
two-dimensional surface?
12 Do these visual clues apply to all humans? If not why
not?
13 List the groups of psychological factors that influence
our visual perception.
2 Show either the ‘faces’ group of cards or the ‘animals’ group, one at a time, to volunteer participants.
3 Show the ambiguous rat-man stimulus (Figure 6.19, page 123) to each volunteer and record the response.
4 Compare the responses of the two groups. Did the ‘faces’ group identify an old man more than the ‘animals’ group?
5 Repeat the experiment with other volunteers, but this time show them a mixture of three ‘faces’ and three
‘animals’ before showing the rat-man stimulus.
> Step 5 is an important step in the research. Why should this be done?

distortions of perception
Visual illusions are mistaken perceptions of visual stimuli. We may misjudge length, curvature,
position, speed or direction in a visual illusion. It is the brain that is tricked, not the eye!
A visual illusion occurs when perception consistently differs from objective reality.
the ponzo illusion
In the Ponzo Illusion, for example (Figure 6.20), the upper horizontal line is perceived to be longer
than the lower horizontal line. Why? We mistakenly perceive this because of the depth cues of linear
perspective and height in visual field—both of which make the upper line appear to be further from us.
Because it casts the same-size image on the retina, we perceive the ‘more distant’ line to be longer.
fig 6.20>> The Ponzo Illusion
the müller-lyer illusion
Another illusion, the Müller-Lyer Illusion (Figure 6.21), consists of two lines of equal length, each
having opposite-shaped patterns on the ends. One line has regular arrowheads; the other has
inverted arrowheads (feather-tails). The line with feather-tails is perceived as being longer than the
arrow-headed line.
There are two theories to explain the Müller-Lyer Illusion.
The carpentered world hypothesis
The carpentered world hypothesis (Figure 6.22): British psychologist Richard Gregory believes that
the illusion involves the ‘misapplication of size constancy’. In a three-dimensional world, we maintain a
constant perception of the size of a familiar object by considering its distance from us. Gregory argues
that we mentally make a three-dimensional form of each figure, using familiar features of buildings to do
so. This causes the observer to perceive the arrow-headed line as the leading vertical edge of a building’s
outer wall (closest to the observer). The line with the feather-tails is perceived as being further away
(the inside corner of a room). Because it is perceived as being the more distant of the two, and each line
produces an equal length image on the retina, we interpret the line with feather-tails to be longer.
Evidence to support this theory came when the illusion was shown to country-dwelling Zulu
people who live in round huts with rounded doors and windows. They did not perceive the lines to
be different lengths as they had never learnt to judge distance from corners and angles. Zulu people
living in cities in South Africa were fooled by the illusion like everyone else.
The perceptual compromise theory
Ross Day, an Australian psychologist, proposes a different theory.
1 Both parallel lines cast identical-sized images on the retina.
2 The arrowhead or feather-tail lines at the ends of the figures create ‘open’ figures that cause us to
apply the Gestalt principle of closure.
fig 6.21>>
The Müller-Lyer
Illusion—which
vertical line is
longer?
125

chapter 6>> visual perception
fig 6.22>> Which room has the higher walls?
3 This creates a more ‘solid’ figure as shown by the blue
lines in Figure 6.23.
4 Because of the perceptual compromise made, we
perceive each figure to be the length of the average
between the internal (black) line and the external (blue)
lines (see Figure 6.24).
5 As a result of this, figure A is perceived to be much
shorter than figure B, each being perceived to be as
long as the distance between the green lines shown
in Figure 6.24.
Evidence in support of this theory is that the illusion
occurs even when the ends of the lines are ‘U’-shaped or
completed circles.
6.4 investigate
126
Extend your knowledge
Isn’t it amazing how we often look at the full moon
on the horizon and it appears to be huge—yet that
same night, if we look at the moon when it’s high
in the sky, it looks normal size! Perform an Internet
search for ‘Moon Illusion’. Explain how this illusion
occurs.
fig 6.25>> If the arrow ends are replaced with ‘U’ shapes
or circles, the illusion still occurs.
A B A
B
fig 6.23>> The blue lines
show how our mind applies the
Gestalt principle of closure so
that Figure B appears larger.
fig 6.24>> Our mind averages
out the black and blue lines
and we perceive the length as
shown by the green lines.

the ames room illusion
The Ames Room shows that we maintain shape constancy (of the
room) at the expense of size constancy.
The room is constructed in a trapezoidal shape, but made to
appear square when observed through a peephole. It is necessary
to prevent the use of both eyes, so that the strongest (binocular)
depth cues do not work. The rear wall actually runs from right to
left, away from the viewer. The far-left corner is twice as far from
the peephole as the far-right corner. To add to the illusion, the
ceiling is not parallel to the floor. It slopes upwards from right
to left, while the floor slopes downwards from right to left, so
that the height of the room at far left is double that at far right.
When a person walks from the left corner to the right corner, the
observer maintains shape constancy, but cannot also maintain size
constancy—so the person appears to be growing rapidly in size.
review 6.4
1 Describe the Ponzo Illusion.
2 Draw some of your own Müller-Lyer illusions and
try them out on your fellow students.
3 Do these visual clues apply to all humans? If not why not?
4 Explain why the Ames Room Illusion occurs.
5 Why does the person who is viewed through the peep-hole
appear to grow and shrink before your eyes?
6 Go to www.illusionworks.com. Create a PowerPoint
presentation of one other illusion and explain why this occurs.
7 M.C. Escher is a famous lithographic artist who created many
impossible figures. Perfom an Internet search for M.C. Escher
and prepare a presentation on his work.
6.5 investigate
Visual illusions
1 How do visual illusions occur?
2 There are two theories to explain the Müller-Lyer Illusion. Choose one
of these theories and briefly outline the key points.
3 How does the Ames Room work? Describe the construction and how
this influences what is seen when looking through the peephole.
4 Using the Internet, search ‘visual illusions’ and create a PowerPoint
presentation of the illusions you have found to share with the class.
Make sure that you define ‘Visual Illusions’ at the beginning of your
presentation and create at least 10 slides.
fig 6.26>> The Ames Room is not really rectangular,
but because of our lifetime of experience with
rectangular rooms, we perceive it to be bounded by
right-angles. In fact the ‘smaller’ person is simply twice
as far from the observer as the ‘larger’ person. The
shape of the room is shown below.
127

chapter 6>> visual perception
chapter summary
> We come to interpret the reality of our visual world
through the body and mind working together to
enable the process of visual perception.
> Perceptual processes are considered to be adaptive—
our sensory systems (smell, taste, touch, vision, hearing)
have evolved to ensure our survival as a species and to
assist us in reproduction.
> The six stages of visual perception are:
1 Reception: when light energy enters the eye and
is focused on the retina
2 Transduction: when the light energy is converted into
nerve impulses by the rods and cones of the retina
3 Transmission: when the nerve impulses travel via
the optic nerve to the occipital lobes at the rear
of the brain
4 Selection: when the image is pulled apart by cells
called feature detectors that respond to lines of a
certain length, orientation or direction of movement
5 Organisation: when visual information reaching
the brain’s visual cortex is reorganised using three
groups of visual perceptual principles
6 Interpretation: when the brain’s temporal lobes
identify the object by comparing incoming
information with information already stored in
memory, and the parietal lobes assist in judging
where the object is in space.
> The energy that enables us to see (light energy) is
the visible part of the electromagnetic spectrum—
wavelengths between approximately 360 and 760
nanometres (1 nm = 1 billionth of a metre).
> For a visual stimulus to be perceived by a person, it
must reach absolute threshold. This is the minimum
128
amount of light energy needed for an observer to
perceive a stimulus in ideal conditions 50 per cent of
the time.
> The retina, which covers over 50 per cent of
the back of the eye, contains two types of
photoreceptors. The 125 000 000 rods in each
eye are responsible for vision in low light and for
peripheral vision; they only register black and white.
The 6 500 000 cones in each eye are responsible for
vision of detail, and colour vision (and black-and-
white vision in daylight).
> The visual perceptual principles include perceptual
constancies, which enable us to maintain a stable
perception of a stimulus in terms of size or shape;
Gestalt principles (the phi phenomenon, figure-
ground, closure, proximity and similarity), which
relate to the tendency for our visual system to
perceive what we see as a meaningful whole; and
depth and distance cues, which govern our ability
to view the world in 3-D.
> Binocular (requiring two eyes) depth cues are retinal
disparity and convergence. Monocular (one eye)
depth cues are accommodation and pictorial depth
cues (linear perspective, interposition/overlap,
texture gradient, relative size, height in the
visual field).
> Previous experience, motivation, emotion and
context can influence the way we perceive a visual
stimulus. This is referred to as perceptual set.
> Visual illusions are mistaken perceptions of visual
stimuli that occur consistently. They may include
misjudgments of length, curvature, position, speed
or direction. The Ponzo, Müller-Lyer, Ames Room
and Moon illusions are well-known examples.

test your understanding
1 Which of the following statements concerning the
stimulus energy for vision is incorrect?
a Electromagnetic energy of about 380
nanometres is perceived as blue or violet.
b Electromagnetic energy of about 760
nanometres is perceived as red.
c Electromagnetic energy of about 380
nanometres is not visible to humans.
d Electromagnetic energy of about 800
nanometres is not visible to humans.
2 Rods are most responsive to electromagnetic energy
of which colour?
a violet/blue
b blue/green
c green/yellow
d orange/red
3 Which of the following lists the groups of visual
perceptual principles that we use to organise and
help interpret stimuli?
a perceptual constituencies; Gestalt principles;
depth and distance cues
b perceptual set; Gestalt principles; expectancies
c depth and distance cues; perceptual
constancies; Gestalt principles
d visual illusions; Gestalt principles; depth and
distance cues.
4 Which of the following correctly pairs the names
of two sets of visual perceptual principles with
examples from those sets?
a Gestalt principles—linear perspective; depth
and distance cues—convergence
b perceptual set—expectancies; Gestalt
principles—closure
c depth and distance cues—retinal disparity;
Gestalt principles—orientation constancy
d Gestalt principles—figure-ground; depth and
distance cues—texture gradient.
5 As I was driving along the freeway a huge truck
came hurtling up behind me. It seemed to take ages
for the long body to get past as it overtook me.
Afterwards it gradually disappeared up the road in
front of me. Which of the following principles would
I have applied to help me realise that the truck
remained the same object although its image on my
retinas changed?
a shape constancy and size constancy
b size constancy and orientation constancy
c brightness constancy and orientation constancy
d brightness constancy and size constancy.
6 In the figure below, we tend to perceive a building,
rather than a series of disjointed lines.
Which two Gestalt principles are mainly responsible
for this perception?
a closure and similarity
b closure and figure-ground
c figure-ground and similarity
d similarity and figure-ground.
7 The binocular depth cues are:
a linear perspective and convergence
b retinal disparity and accommodation
c relative size and linear perspective
d convergence and retinal disparity.
8 The strongest depth cues are:
a convergence and retinal disparity
b linear perspective and convergence
c pictorial cues
d monocular cues.
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chapter 6>> visual perception
test your understanding
9 One evening I saw a crowd of tiny dots in the sky.
These dots became larger and suddenly a large flock
of mutton-birds began to land. I was not surprised
that the dots I had seen in the distance were actually
big sea-birds because I had applied the principle of:
a shape constancy
b orientation constancy
c brightness constancy
d size constancy.
10 Jack and his team were doing fielding practice,
catching a ball that the coach hit high in the air.
After a few people had dropped catches, the coach
insisted that all players hold their hands in front of
their face and watch the approaching ball through
their fingers. Jack was surprised that his success
rate improved using the new technique. What is the
reason for his improved performance?
a Using the new method, he could use
convergence and retinal disparity cues to help
him judge depth and distance.
b Using the new method, he could use
accommodation and convergence cues to help
him judge depth and distance.
c Using the new method, he could use pictorial
cues to help him judge depth and distance.
d Using the new method, he could use monocular
cues to help him judge depth and distance.
11 In drawing a landscape, John used the cue of height
130
in the visual field to give the impression of depth and
distance. This meant that:
a objects that were further away were drawn
higher up in the plane of the picture
b objects that were further away were drawn lower
down in the plane of the picture
c objects that were further away were drawn
closer to the horizon in the picture
d objects that were nearer the horizon were drawn
smaller than similar objects in the foreground.
12 As her family was driving across to Perth from
Melbourne, seven-year-old Jodi called out, ‘Look
Mum, there’s hundreds of rabbits!’ As they gradually
got closer, Jodi said ‘Oh! They’re actually great big
kangaroos!’ What had caused Jodi’s initial error of
perception?
a previous experience with rabbits, causing a
perceptual set that led to selection of specific
parts of the scene to be attended to
b previous experience with rabbits, causing
a perceptual set that led to a particular
interpretation of the scene
c the context in which the animals were seen,
causing a perceptual set that led to selection of
specific parts of the scene to be attended to
d the context in which the animals were seen,
causing a perceptual set that led to a particular
interpretation of the scene.
13 Psychologist Colin Turnbull took a pygmy from the
rainforests of South America to the plains of Kenya in
Africa. The pygmy looked at the herds of thousands
of wildebeest in the distance and perceived them to
be a large colony of ants a few metres from him. The
reason for this error in perception is:
a previous experience with ants, causing an
expectancy that led to selection of specific
parts of the scene to be attended to through
perceptual set
b previous experience with ants, causing an
expectancy that led to a particular interpretation
of the scene through perceptual set
c the context in which the animals were seen,
causing a perceptual set that led to selection
of specific parts of the scene to be attended to
through perceptual set
d the context in which the animals were seen,
causing a perceptual set that led to a particular
interpretation of the scene through perceptual
set.

14 The Ames Room Illusion is one in which we
mistakenly perceive a person to change in size as
they cross a room. The illusion is caused by the fact
that we:
a maintain size-constancy for the room at the
expense of size-constancy for the person
b maintain shape-constancy for the room at the
expense of shape-constancy for the person
c maintain size-constancy for the room at the
expense of shape-constancy for the person
d maintain shape-constancy for the room at the
expense of size-constancy for the person.
15 The Müller-Lyer Illusion is one in which we mistakenly
think that one parallel line is longer than the other
because of the pattern on the end of each of the
lines. The best description of the illusion is that:
a the line with the arrowheads on the ends is
perceived to be shorter than the line with the
feather-tails on the ends
b the line with the arrowheads on the ends is
perceived to be longer than the line with the
feather-tails on the ends
c the two lines are perceived to be the same
length but at different distances from us
d the two lines are perceived to be the average
length of the outermost and innermost
measurements.
16 When we are in broad daylight looking at an object,
we like to look straight at it and hold it in the centre
of our visual field. When it is almost dark, we cannot
pick out colours and we see objects better when they
are on the edge of our field of view. With reference
to the retina and photoreceptors, explain why this is
the case.
17 The processes that are carried out by the
photoreceptors during visual perception include
reception, transduction and transmission.
Explain what is meant by transduction.
Explain what is meant by transmission.
18 With reference to the picture shown below, identify
four depth cues that are shown and describe how
each one enables us to perceive depth in this
picture.
19 Explain, using an example, the Gestalt principle of
similarity.
20 Explain what is meant by the term ‘perceptual set’.
Give an example that shows your understanding of
this principle.
21 The Ames Room Illusion is a visual illusion.
a Define ‘visual illusion’
b i Describe the Ames Room Illusion.
(Be careful to state what is perceived.)
ii Why does the illusion occur?
131

unit 1 aos 1>> research methods and ethics
research methods and ethics
132
1 case study
Tuskegee Study of Untreated Syphilis in Negro Males
Syphilis is a sexually transmitted infection and can
affect both men and women. It is transmitted through
close skin-to-skin contact and is highly contagious. It
can also be passed on by an infected mother to her
unborn child. If left untreated, it can damage the heart,
brain, eyes and bones with fatal consequences.
The Tuskegee Study of Untreated Syphilis in Negro
Males was a clinical study that began in 1932 and
ended in 1972 and recruited 399 males with syphilis
and 201 males without syphilis (the control group).
The main organisations involved in the study were
the Tuskegee Institute (a historically black college)
and the Public Health Service Venereal Disease Clinic
in Arkansas. Most of the African American males
recruited to be in the study were poor and illiterate
and were told they had ‘bad blood’. As an incentive to
participate, they were offered free medical treatment,
transportation to the clinic, meals and burial insurance
in case of death.
Questions
Complete the following with reference to this research.
1 When did the Tuskegee experiment begin?
2 How were participants selected?
3 How many participants were involved in the study?
4 What experimental design was used (e.g. matched participants, independent groups,
repeated measures)?
5 Were participants offered any incentive(s) to participate in the study? If so, what ethical
principle was breached?
6 What year did the experiment begin?
7 Explain what ‘syphilis’ is and how it is acquired. Use the Internet to give additional
information to answer this question.
8 What was the aim of the experiment?
9 How did the researchers track the effects of syphilis on the participants?
10 Why is this experiment considered unethical by today’s standards? Explain your answer with
reference to the ethical principles outlined in Chapter 1.
11 What were the long-term problems caused by this experiment?
When the study began in 1932, treatment of syphilis
was often unreliable and many of the medications
used were toxic. The researchers wanted to observe
the progression of the disease and subjected the
participants to dangerous and painful procedures
without actually treating their syphilis. The study also
required all participants to undergo an autopsy after
their death in order for their families to receive the
funeral benefits promised. In 1947, penicillin became
the standard treatment for the disease with excellent
results. However, the participants in the study who
were diagnosed with syphilis were not given treatment.
Some were given a placebo (not the real treatment).
At the end of the study, only 74 of the original
test subjects survived. Twenty-eight of the men died
directly of syphilis, 100 died of related complications,
40 of their wives had been infected and 19 of their
children were born with congenital syphilis.
Reference:

2 case study
The Aversion Project
Aversion therapy is a treatment which has sometimes
been used to stop people smoking or engaging in
other unwanted behaviours. The patient is exposed to
the stimulus (the source of unwanted behaviour, e.g.
smoking cigarettes) and at the same time subjected
to something unpleasant (e.g. electric shock, physical
pain or a nausea-inducing drug). This process is
repeated until the patient begins to associate the
stimulus (cigarette) with the unpleasant consequence.
This method was used in the South African armed
forces to ‘cure’ homosexuality.
From 1971 to 1989 South Africa’s apartheid army
wanted to eliminate homosexuality in their army.
White lesbian and gay soldiers were forced to undergo
‘sex-change’ operations and many were subjected to
Questions
Complete the following with reference to this research.
1 What was the aim of the Aversion Project?
2 Write a hypothesis on which such a project is based.
3 Explain what aversion therapy involves.
4 What methods were used on soldiers to change their sexual preference?
5 What ethical principles were breached in this experiment? Identify as many as you can and
explain them in terms of the experiment (refer to Chapter 1).
6 Could this experiment be replicated/repeated today? Explain your answer.
7 MKULTRA was the code name for a covert CIA research program run by the Office of
Scientific Intelligence on mind-control and chemical interrogation. Using the Internet
to research, write approximately 250 words outlining the aim of the project and what it
involved. What ethical principles were breached in this experiment? Outline as many as you
can and explain each one in relation to this program.
chemical castration, electric shock, and other invasive
medical procedures. According to former apartheid
army surgeons, approximately 900 people were forced
to have ‘sexual reassignment’ operations at military
hospitals as part of a top-secret program to get rid of
homosexuality from the armed forces.
Army psychiatrists and chaplains were instructed
to expose suspected homosexuals in the armed
forces and send them to military psychiatric units
for ‘treatment’. Those who could not be ‘cured’ with
drugs, aversion shock therapy, hormone treatment and
other ‘radical’ psychiatric methods, were chemically
castrated or given sex-change operations. Most of the
victims were white males aged 16 to 24 years who were
drafted (forced) into the apartheid army.
133

unit 1 aos 1>> assessment activities
assessment activities
The following assessment tasks cover a range of topics from
chapters 2 to 6 and are designed to assist you in gaining a
deeper understanding of the information covered.
research investigation
Investigate people’s perception and understanding of the
roles of psychologists and psychiatrists.
Working in pairs, construct a short survey to find out what
people actually know about psychiatry and psychology.
>
>
>
>
>
Each pair is to survey at least five people.
Think of at least 7–10 different statements that relate
to either a psychiatrist or a psychologist. (Note: do
not write statements that are relevant to both.)
Note both correct responses and incorrect responses.
Collate the data.
Formally write up this research investigation,
following the criteria outlined on page 36.
annotated folio of practical
activities
Guided by your teacher, select a range of activities from
chapters 2 to 6 to present for assessment, for example:
>
>
one research investigation per chapter
written responses to the Review items in chapters.
The activities should be presented in the manner as
instructed within the text or by your teacher.
media response
Using a range of sources, such as newspapers, the
Internet or magazines, find an article on psychology
research related to the biological approach.
>
>
>
>
>
>
>
134
What is the article about?
Is it about human or animal subjects?
Is the information presented in a scientifically valid
and accurate manner? Explain.
What was the aim of this research?
Suggest a research hypothesis.
What did the researchers conclude?
How reliable was the source? Explain.
oral presentation
Select one of the following topics and present your findings
using a PowerPoint presentation or podcast.
>
>
Career options for psychologists. Include the range
of specialties and statistics on their numbers.
The cognitive approach. Include the focus of this
approach, the main researchers and their contribution
to knowledge of mental processes and behaviour.
visual presentation
Create a concept map, graphic organiser or poster on
one of the following:
>
>
essay
The biological, cognitive, behavioural and
sociocultural approaches in psychology and what
each has contributed through its research.
The differences between psychology as a science
and pseudo-sciences.
Write an 800-word essay on one of the following topics.
Refer to relevant theories to support your statements.
>
>
Write a persuasive essay on the question ‘Are
pseudo-sciences dangerous or is the scientific
community simply closed-minded?’
Psychology is said to have developed from the
discipline of philosophy. Explain this in terms of the
contributions made from ancient times.
debate
Choose one of the following topics for your debate:
>
>
Violent video games and movies have little effect on
adolescent behaviour.
Animal research is necessary for furthering our
knowledge in psychology.
data analysis
Using the data collected in the research investigation
above, calculate the mean, median and mode. Draw
appropriate table(s) and graph(s) to show your results.

assessment rubric
Possible total = 20 marks
Criterion 4 marks 3 marks 2 marks 1 mark
1 Communication
clear and concisely written
information
persuading effectively
reading independently
listening and understanding
2 Planning and organisation
collecting, analysing and
organising information
planning the use of resources
time management
3 Presentation of task
use of technology to organise
and present data
speaking clearly and directly
visual presentations
written work follows the
conventions of formal writing
4 Understanding
historical beginnings and
different approaches of
psychology
differences between
psychology and pseudosciences
processes visual perception
5 Analysis
analysis of topic
ability to compare and contrast
different information
6 Research
a range of resources have
been identified and used
resources are all cited using
correct format within the text
and in the reference list
All of the relevant
aspects of this
criterion have been
fully and effectively
addressed and
expressed
Effective planning, use
of time, and use of
resources to maximise
completion of the task
Appropriate and
effective use of
relevant format to
present the task
Clear and complex
understanding of the
topic as evidenced
in the standard of
information in the task
Evidence of complex
analysis of the topic
and competent
contrast/comparison
of information or
concepts
Effective use of a
comprehensive
range of relevant
and appropriate
resources to address
the requirements of
the task, and correct
citation of sources
N.B. For all criteria, 0 marks are awarded for ‘not shown’.
Some of the relevant
aspects of this
criterion have been
fully and effectively
addressed and
expressed
Some effective
planning, use of time,
and use of resources
to complete the task
Appropriate and some
effective use of the
relevant format to
present the task
Clear understanding
of the topic shown
in the standard of
information included
in the task
Evidence of analysis of
the topic and sound
contrast/comparison
of information or
concepts
Use of a range
of relevant and
appropriate resources
to address the
requirements of the
task, and correct
citation of sources
Some of the relevant
aspects of this
criterion have been
addressed
Partial evidence
shown of planning,
use of time, and use of
resources
Appropriate use of
the relevant format to
present the task
Some understanding
of the topic and basic
information evident in
the task
Some evidence
of analysis of the
topic and basic
contrast/comparison
of information or
concepts
Use of some relevant
sources to address
the requirements of
the task, with some
attempt to cite
sources
Some of the relevant
aspects of this
criterion have been
vaguely addressed
Insufficient evidence
shown of planning,
use of time, and use of
resources
An attempt has been
made to use the
relevant format to
present the task
Partial understanding
of the topic and
limited accurate
information evident in
the task
Little evidence of any
analysis and basic
contrast/comparison
of information or
concepts
Limited use and
citation of sources
Your teachers will indicate which aspects of each criterion are applicable to the relevant assessment task that has been set for their class.
135