PRINCPLES AND PRACTICAL APPLICATIONS OF PERCEPTION

1-AP

GROUP NO. 2

Members:

Feria, Denice N.

Planas, Bianca Wynona Alexis

Roxas, Milicent Daphnie

Sena, Princess Genevieve

ACCOMPLISHMENT REPORT

In doing the paper, we have a rough time in collecting all the details about perception. I,

as the leader of our group was very worried if we can finish the said paper before its due date. I

point out Milicent to be responsible about the principles especially about the Gestalt Principle.

Rosebelle did a great part to our paper because all of the things I needed in this paper are on the

research that she passed to me. Bianca is the one responsible for contributing in our introductory

part. Also, Princess had a rough time in researching about the factors that influence perception

but she did pass it on the exact time. I collected their research papers and combine them into one.

I’m lucky that I have members like them. They are the one representing if what they will do in

this paper. We gather many researches and data as well as images. We did not copy then paste it

but we understand first and we construct our own details according to what did we understand.

We only copy those important things that many psychologists quoted. Perception is a very

narrow subject to understand and make a paper like this out of it. Because of this paper, we have

great time in participating with each other. Princess is very thankful to me that they have a leader

like me. She said that I’m doing the best for the accomplishment of this paper. Bianca even

though she is not a regular student, she always approaches me in what is happening on our term

paper. Milicent even though she is busy, she passes any research details that has a connection on

what is the topic all about. I hope that many people will appreciate what we did. Because I and

my members did everything to put all the information we must gather in order for the others to

learn from it.

Enjoy reading it and if you have some questions to ask, only approach me and also my

members and we are willing to answer.

Denice N. Feria

ACCOMPLISHMENT TABLE FOR MARKING

NAME RESEARCH

( 30)

DISCUSSION

(20)

PAPER-

MAKING

(40)

CONTRIBUTION

(10)

TOTAL

GRADE

(100)

FERIA,

DENICE N.

IGNACIO,

ROSE BELLE

PLANES.

BIANCA

WYNONA

ALEXIS

ROXAS,

MILICENT

DAPHNIE

SENA ,

PRINCESS

GENEVIEVE

TABLE OF CONTENTS

CHAPTER 1

INTRODUCTION TO PERCEPTION

LESSON1: What is Perception?

LESSON 2: How does perception works?

LESSON 3: What is the importance of perceiving?

- Advantages and Disadvantages of Perceiving

- How is it related to Sensation

CHAPTER 2

BODY of the TERM PAPER

DEVELOPMENT OF PERCEPTION

LESSON 1: Perception in the critical period (Infancy)

LESSON 2: Childhood vs Adulthood

LESSON 3: Classification of Perception

- Depth Perception: Types of Cues

- Color Perception

- The Constancies: Size, Shape and Brightness

CHAPTER 3

PERCEPTION CONCEPTS AND ITS FACTORS

LESSON 1: Perception and Reality

LESSON 2: Perceptual Illusions

LESSON3: Perception in Action and Events

LESSON 4: FACTORS THAT INFLUENCE PERCEPTION

CHAPTER 4

GESTALT PRINCIPLES AND PERCEPTUAL APPLICATIONS

LESSON 1: Gestalt Principles

LESSON 2: Perception in Sciences

REFERENCES

Chapter 1: INTRODUCTION TO PERCEPTION

What is PERCEPTION?

There are many things here on earth that we possessed. In everyday of our living, we are

holding in all things we perceive in the way we like it. The world is filled with objects that we

can used up to be contented and to be happy with. Not only happy, but we can get information

from this through the help of the language of the mind, specifically speaking – the nervous

system. But as we used up the things we have in our environment, curiosity and awareness rise.

These two factors affect our mind, our interaction to our environment changes. This lead

ourselves to see what we must see, perceive what must we feel- so called “PERCEPTION”

born.

Psychologists always make distinction between sensation and perception. The two have

much resemblance on one’s self but there are different characteristics in how they differ.

Sensation includes the physiological processes in dealing the information. We use our eye, ears

to take the stimuli and register them in the language of the nervous system. From the brain, it

reacts and transfers it to every part of the body, transfers electrochemical messages into a rich

percept and psychological process happen. The psychological process involved in interpreting

these sensations is what we called perception.

Perception makes us in contact with the things here in our environment. The knowledge,

curiosity, awareness that making the world touchable and perceivable is caused by the perception

we possessed. Perception is a method in which we give meaning to sensation. We interpret the

things we feel and we act that in our everyday living. Perception is like we survive on some

circumstances in our life. Because like circumstances, perceiving the world is a great challenge,

if we can’t perceive what is undesirable from desirable one, we can’t merely understand how the

world works for. But perception does not require us to perfectly detailed or perceive one’s view

on the things here on earth. Perception is an achievement because through your curiosity and

knowledge about the environment, you certainly, perhaps interact with the environment out of

the world of consciousness and awareness. Take into consideration the pictures below:

BACK FRONT

What can you see at the pictures? Maybe you are conscious or maybe your distinguishing

in the pictures are wrong. How come that it is a dog and not a woman? As we say a while ago,

perception does not require us to be perfect in all we perceive. Perception is an engineered one.

Why? Because we are the one making it! As we make it, we may even misrepresent the true

picture. But remember, even though we have our misrepresentation, very much indeed it is more

important that we are interacting to the things here in our environment effectively. Chances in

taking objects are given to us so we must grab it. Perception is a fast process and no machine can

detect how fast and flexible a perception of one person is.

Like a person, every perception is unique. No perception is likely the same in common

time and place. Like individuals, no person can act in same manner and attitude in the same

instances. It is like those two men are standing on one particular place looking on a picture. The

first man will see the picture different in the way in interpretation of the other man. Our

environment generates a powerful stream of sensory information. The fact that there are many

objects and events that perception can’t possibly process and respond to each one of that object.

Perception does work. How? As we perceive, we tend to become much curious on how accurate

our perception is and then we do things to prove that. But sometimes, we doubt on what we see,

what we hear just like as thinking on what we eat and what we do. For one thing, the world is

composed of physical nature of matter and energy. These gave us many materials or subjects on

what we can possess in order to do discriminations and detection through perceiving. For

example, the light coming from our vision can bring us to see our shadows or not only shadows

but also the people in our everyday living. Vision and audition are the primary modes through

which information cycles on into the world.

On the next discussion on this topic we will see how perception works into the minds of

people especially on the information on the primary two modes of getting information on our

environment.

How Perception works?

Perceiving always require an action on the particular thing which he/ she perceive.

Perception is an active process. Why? It is because in every object or event in this world that we

perceive, we are always making a force or a work. This is what we called psychophysics. An

expert named James J. Gibson (1966) quoted that, “We must perceive in order to move, but we

must also move in order to perceive.” Being active in perceiving means that you have the goals

to successfully reach your goal to represent and interact in an object in an accurate way. In this

manner, we are using our environment in a useful way.

This picture states how perception works into the mind of people.

Perception can be interpreted in the simplest manner we know. When we are hungry, or

sleepy, even when we are angry or lonely, that is how we actively perceived our thoughts.

Perception brings intelligence to someone actively using it. Therefore, your behavior almost

depends on what you perceive. Perception works on every single moment in our life. Even a

baby can perceive his/ her own will.

Factors that influence perception

Perception is also a form of learning. Learning in such a manner that no one can teach us

what we must perceive but it is our mind which will control it. Perception’s links to action

produces an interesting distinction among our senses that has to do with the proximity of the

perceiver to the object of perception. Perception is a stage on which will develop as an infant

transform into adult. The table below shows how perception becomes a source for learning.

This is how perception works when we are reading.

Importance of Perception

Advantages of Perception

1. You will learn to exploit the nature and the regularities of nature through the help of

sensation.

2. As perception deals and uses up the environment, it simply ignores the other things

happening here on earth.

- Perception is like a person that can’t do two tasks at the same time. We can perceive

in two things with same perception but we can’t perceive in two perceptions in one

thing at the same time and place. It always requires time on which our mind regulates

in order not to misinterpret any single perception.

3. Perception is mutually interdependent with the other perception of people but it stays the

uniqueness of one’s perceiving it.

- We are capable of dealing not only in the environment itself but also to the people

who also uses the world. Even though we don’t have the same perception in some

place or time, we are mutually understanding why we uses the environment, why we

must be satisfied in our daily living and mostly why we must live in this world of

perception.

4. Perception is enjoyable to study with.

- Perception is important in solving a certain problem for some reasons. Because of the

curiosity of the people, they can perceive in an extraordinary way that others can’t do.

Disadvantages of Perception

1. Perception sometimes leads to misunderstanding and misinterpreting of one’s behavior or

picture.

Misinterpretation

2. Perception leads to pleasure.

- Lifestyle has been always traditional to us. It is always varies from tribe to tribe. It

always changes for generation to generation. Visuals, audition and many others. But

as they enjoy their selves in perceiving the world many instances just like the

limitation of perception does not exist anymore. Every little thing even the mind has

its own limitation.

Too much perception

3. Perception leads to illusions

- Illusions affect person one’s personality and even behavior. It becomes more

traditional in some manners that we can possess such things here on earth immortally

or extraordinarily. These illusions will make our perception wrong and this will lead

to mistakes which can cause breakage to one’s concentration.

How is it related to SENSATION?

A complete understanding of perception is how we perceive things using our senses. We

must know the object by seeing. We must do feel it by touching. We always use our senses in

order to achieve a complete perception. In addition to this, we must specify what limitations we

have in order to control our perception. We must also know how we can detect these limitations

for us to help other people in controlling the nature of perception. We must stand the behavioral

consequences of sensory stimulation, for our actions will modify those very patterns of sensory

stimulation. These sensory stimulations will lead us in some challenges.

Our nervous system plays a central role in our perception. A specialized brain will help us in

order to learn the neuron impulses that join in the connection of perception. This brain will then

carry sensory information including how the activity distributed among those many areas is

combined to form our unified sense of the world.

Human brain and neuron impulses

People have three basic methods of perceiving the world around them:

Visual (see the world)

Auditory (hear the world)

Kinethetic (feel the world).

Individuals have different preferred ways of thinking and communicating their experiences –

some express themselves in pictures, others talk about how things sound to them, and others

speak about how things feel. If you want to connect with your target customers, you have to:

figure out which sense they favor

use right predicates to establish rapport with them

Let the visuals see, the kinethetics feel, and the auditories hear about the unique benefits

your product/service offers to them to wake their emotions up.

Common Senses in perception:

1. Proprioception, the kinesthetic sense, provides the parietal cortex of the brain with

information on the relative positions of the parts of the body. Neurologists test this sense

by telling patients to close their eyes and touch their own nose with the tip of a finger.

2. Mechanoreception, which is the perception of pressure or vibration on the skin

3. Thermoreception, which is the perception of heat

4. Nociception, which is the perception of pain

"We are constantly bombarded with so much sensory information that it is impossible for

us to pay attention to everything. Our subconscious mind scans our environment and selects

what it deems may be important for us to notice. Even then, people not only see things the

way they are, they also tend to see what they expect to see, as well as what they want to see."

"Much of human perception is based not on information flowing into the brain from the

outside world but what the brain, based on previous experience, expects to happen next,” says

Sandra Blakeslee, an award-winning science writer for the New York Times.

Our perceptual experiences are always characterized on how our brain works. Touch and

taste require direct contact between the perceiver and the source of stimulation. The sense of

smell is also effectively a near sense for humans, but for animals it depends on what

characteristic of animal it possesses. The eyes and ears can pick up information originating from

far distances or sources. They are like “radars”. They are called far senses. The distinction

between these two senses has their own advantages and disadvantages but no matter what it is,

our perception lies in it and whichever sense we will use it depends on how our brain works for

it.

Five Senses

Chapter 2: Development of Perception

Perception in Critical Period (Infancy)

Perception is one of the oldest fields in psychology. The oldest quantitative law in

psychology is the Weber-Fechner law, which quantifies the relationship between the intensity of

physical stimuli and their perceptual effects (for example, testing how much darker a computer

screen can get before the viewer actually notices). The study of perception gave rise to the

Gestalt school of psychology, with its emphasis on holistic approach.

Philosopher Andy Clark explains that perception, although it occurs quickly, is not

simply a bottom-up process (where minute details are put together to form larger wholes).

Instead, our brains use what he calls predictive coding. It starts with very broad constraints and

expectations for the state of the world, and as expectations are met, it makes more detailed

predictions (errors lead to new learning processes). Clark says this research has various

implications; not only can there be no completely "unbiased, unfiltered" perception, but this

means that there is a great deal of feedback between perception and expectation (perceptual

experiences often shape our beliefs, but those perceptions were based on existing beliefs).

The critical period of development of perception is the time during which the infant

animal or human must have a certain experience in order to develop.

A baby playing has already a perception on what he’s doing.

It is difficult to assess infant’s perceptual abilities because their motor and verbal skills

are so limited that they cannot inform what they want to say or their perceptual capabilities.

Similarly, psychologists have been forced to invent clever methods are a major reason for our

altered assessment of the infant person in recent years. Most of the methods are variations of one

of the three basic methods: preference, habituation, and conditioning.

A baby does not know yet what he/ she perceive.

Three Common methods in which we can measure the perception of an infant:

1. Preference method- it is based on the idea of an infant on how long he/ she is looking to

the object. Two figures are to be subjected in the infant and he/ she will see that

according to the choice of the infant. Discrimination between two figures can be

distinguished by the facial expression or the manner of the infant on how they look at it.

2. Habituation Method- decrease in attention to repeated stimulation. Because of the

discrimination lead due to preference method, they adapt the picture because there is a

decrease in responsiveness from the sensory receptors. When a baby pays less attention to

an object that has been presented several times by the preference method, the baby is

demonstrating that he or she remembers seeing the object.

3. Conditioning method- the experimenter selects a response that the baby can make and

delivers a reward when the baby makes that particular response. Generalization comes

into this method and the experimenter will know what the visual perception of an infant

is.

Visual perception is important to the infants because this is the first stage they must be

aware of. How about their other senses? Infants have accommodation abilities although they are

not equivalent to adult’s abilities. Newborns have somewhat higher auditory threshold than

adults, infants as young as 2 months show musical tunes. When are touched on various parts of

the body, different reflexes are elicited. Babies can imitate adult facial gestures when they are 1

hour old. Babies are sensitive to a variety of odors but it is not clear how early this skill is

acquired. Babies can also make facial expressions to various taste stimuli; they drink more if

there are more sweets served.

GENERALIZATION

Babies have their own uniqueness in responding to this perception. But as they grow

older, they will develop end perform some perceiving techniques that are same with adults now.

Childhood vs. Adulthood

Adult- Child Interaction

CHILDHOOD ADULTHOOD

1. Testing their perceptual abilities is

difficult because of limited tasks given

and motor skills acquired

1. Acuity decreases with the old age;

decline is a particular problem for dynamic

visual acuity.

2. They show inaccuracy in copying figures

due to perceptual immaturity

2. Older adults are slower than younger

adults in visual information processing.

3. They describe figures in terms of its 3. An important consequence of presbycusis

parts, the whole and the relationship of

the two sequences.

is difficulty in speech perception, which is

magnified when speech is distorted or

when there are other loud noises.

4. They are less sensitive than adults to the

orientation of the figure.

- Dyslexia- deficiency in the

orientation of letters

4. Sensitivity to touch decreases as they get

older and older.

5. They can identify familiar objects in a

photograph; they appreciate interposition

as a distance due and sensitive in getting

information.

5. Elderly people are generally less

sensitive to odors but there are

exceptions.

6. Children under age of 5 are unsystematic

and incomplete when they scan pictures.

6. They are generally less sensitive to tastes

but their above- threshold judgments are

different from younger people.

7. They misinterpret tasks instructions. 7. They are less accurate in identifying

food flavors.

8. They are increasingly able to pay

attention to important information and

able to ignore irrelevant information

8. Some sensory receptors are certainly

disabling.

Classification of Perception

Depth Perception: Seeing the Three Dimensional World

- The visual ability to perceive the world in three dimensions (3D) and the distance of

an object.

- The distance between one object and another or between different parts of a single

object called the relative distance.

TYPES OF CUES

1. Oculomotor Cues to Depth- Whenever you are looking to an object, your eyes are

focused and converged by the amount that depends on the distance between you

and the object it. To be seen clearly, close objects require more accommodation

and convergence than do objects farther away from you.

It plays only on a restricted role in depth perception. It is this cue

provided by looking at the world through two separate eyes.

Oculomotor Cues

2. Binocular Cues visual Depth information :STEREOPSIS

- It allows you to judge relative depth with great accuracy and it also enables you to see

objects that are invisible to either eye alone.

- Two aspects: The nature of the stimulus information specifying stereopsis and the

nature of the brain processes responsible for registering that information.

- Stereopsis or retinal(binocular) disparity - Animals that have their eyes placed

frontally can also use information derived from the different projection of objects

onto each retina to judge depth. By using two images of the same scene obtained from

slightly different angles, it is possible to triangulate the distance to an object with a

high degree of accuracy. If an object is far away, the disparity of that image falling on

both retinas will be small. If the object is close or near, the disparity will be large. It is

stereopsis that tricks people into thinking they perceive depth when viewing Magic

Eyes, Autostereograms, 3-D movies and stereoscopic photos.

Binocular Cues

- The major source of binocular depth information is the stereopsis. You can easily

confirm that the world retains a real sense of depth even when one eye is closed.

Rather than collapsing into a single, depthless plane, objects in the visual field

continue to appear three- dimensional. This is possible because the monocular view

of the world contains additional sources of information about depth.

3. Monocular Cues- based on the principles of geometry and based on the conditions

of atmosphere and illumination. Some others are based on visual information

- They are called monocular because the sources of depth information can be realized

by either eye alone.

Examples:

a) Linear Perspective- can be sufficiently robust to contradict depth

information conveyed by retinal disparity.

b) Texture Gradient- provides precise and unambiguous information

about the distances and slants of surfaces, as well as about the sizes

of objects located on surfaces. It also signals the presence of edges or

corners.

c) Aerial Perspective- Objects in distances are seen less clearly than

those closer to you. It occurs because light is scattered as it travels

through atmosphere, especially if the air contains dust or excess

moisture. This scattering of light reduces the contrast and hence,

blurs the clarity of the object.

d) Shading- shadows of objects can give a clue to their distance,

allowing closer objects to cast longer shadows which will overlap

objects which are farther away.  Objects which are closer to the

bottom of our visual field are seen as closer to us due to our

perception of the horizon, where higher (height) means farther

away.  Similar to texture, objects tend to get blurry as they get

farther away; therefore, clearer or crisper images tend to be

perceived as closer (clarity).  

e) Motion Parallax- relative apparent motion of objects within your

field of view whenever you move- which provides a very effective

cue to the relative depth of objects.

f) Overlap- those objects covering part of another object is perceived as

closer.

Color Perception

The properties of color which are inherently distinguishable by the human eye are hue,

saturation, and brightness. While we know that the spectral colors can be one-to-one correlated

with light wavelength, the perception of light with multiple wavelengths is more complicated. It

is found that many different combinations of light wavelengths can produce the same perception

of color. This can be put in perspective with the CIE chromaticity diagram.

Examples of Color Perception

The Constancies: Size, Shape and Brightness

Maintaining Perceptual Constancy

 

Imagine if every time an object changed we had to completely reprocess it.  The next

time you walk toward a building, you would have to re-evaluate the size of the building with

each step, because we all know as we get closer, everything gets bigger.  The building which

once stood only several inches is now somehow more than 50 feet tall.  

 

Luckily, this doesn't happen.  Due to our ability to maintain constancy in our perceptions,

we see that building as the same height no matter what distance it is.  Perceptual

constancy refers to our ability to see things differently without having to reinterpret the object's

properties.  There are typically three constancies discussed, including size, shape, brightness.

 

Size constancy refers to our ability to see objects as maintaining the same size even when our

distance from them makes things appear larger or smaller.  This holds true for all of our senses. 

As we walk away from our radio, the song appears to get softer.  We understand, and perceive it

as being just as loud as before.  The difference being our distance from what we are sensing.

 

Everybody has seen a plate shaped in the form of a circle.  When we see that same plate from an

angle, however, it looks more like an ellipse.  Shape constancy allows us to perceive that plate

as still being a circle even though the angle from which we view it appears to distort the shape.

 

Brightness constancy refers to our ability to recognize that color remains the same regardless of

how it looks under different levels of light.  That deep blue shirt you wore to the beach suddenly

looks black when you walk indoors.  Without color constancy, we would be constantly re-

interpreting color and would be amazed at the miraculous conversion our clothes undertake.

 

CHAPTER 3: PERCEPTION CONCEPTS AND ITS FACTORS

Perception and Reality

In the case of visual perception, some people can actually see the percept shift in their

mind's eye. Others, who are not picture thinkers, may not necessarily perceive the 'shape-shifting'

as their world changes. The 'esemplastic' nature has been shown by experiment: an ambiguous

image has multiple interpretations on the perceptual level. The question, "Is the glass half empty

or half full?" serves to demonstrate the way an object can be perceived in different ways.

Just as one object can give rise to multiple percepts, so an object may fail to give rise to

any percept at all: if the percept has no grounding in a person's experience, the person may

literally not perceive it.

The processes of perception routinely alter what humans see. When people view

something with a preconceived concept about it, they tend to take those concepts and see them

whether or not they are there. This problem stems from the fact that humans are unable to

understand new information, without the inherent bias of their previous knowledge. A person’s

knowledge creates his or her reality as much as the truth, because the human mind can only

contemplate that to which it has been exposed. When objects are viewed without understanding,

the mind will try to reach for something that it already recognizes, in order to process what it is

viewing. That which most closely relates to the unfamiliar from our past experiences, makes up

what we see when we look at things that we don’t comprehend.

This confusing ambiguity of perception is exploited in human technologies such as

camouflage, and also in biological mimicry, for example by European Peacock butterflies, whose

wings bear eye markings that birds respond to as though they were the eyes of a dangerous

predator. Perceptual ambiguity is not restricted to vision. For example, recent touch perception

research Robles-De-La-Torre & Hayward 2001 found that kinesthesia based haptic perception

strongly relies on the forces experienced during touch.

Preconceptions can influence how the world is perceived. For example, one classic

psychological experiment showed slower reaction times and less accurate answers when a deck

of playing cards reversed the color of the suit symbol for some cards (e.g. red spades and black

hearts).

There is also evidence that the brain in some ways operates on a slight "delay", to allow

nerve impulses from distant parts of the body to be integrated into simultaneous signals.

Perceptual Illusions

An illusion is an error in perception such as an optical illusion or auditory illusion.

Muller- Lyer Illusion

- According to the depth theory, the arrowheads on the vertical lines can be seen as angles

formed by two intersecting surfaces.

Muller- Lyer Illusions

Moon Illusion

- Illusion that involves errors in perceived distance and size.

Moon Illusions

Motion Illusion

-seeing an object moving even though it is only stationary.

a. Autokinetic effect- a small , stationary light in a darkened room will appear to move or

drift because there are no surrounding cues to indicate that the light is not moving.

b. Stroboscopic motion- a rapid series of still pictures will seem to be in motion.

c. Phi Phenomenon- similar to the second in which light turned on in the sequence

appear to move.

Motion Illusion

Perception in Action and Events

An ecological understanding of perception derived from Gibson's early work is that of

"perception-in-action", the notion that perception is a requisite property of animate action; that

without perception action would be unguided, and without action perception would serve no

purpose. Animate actions require both perception and motion, and perception and movement can

be described as "two sides of the same coin, the coin is action". Gibson works from the

assumption that singular entities, which he calls "invariants", already exist in the real world and

that all that the perception process does is to home in upon them. A view known as

constructivism (held by such philosophers as Ernst von Glasersfeld) regards the continual

adjustment of perception and action to the external input as precisely what constitutes the

"entity", which is therefore far from being invariant.

Glasersfeld considers an "invariant" as a target to be homed in upon, and a pragmatic

necessity to allow an initial measure of understanding to be established prior to the updating that

a statement aims to achieve. The invariant does not and need not represent an actuality, and

Glasersfeld describes it as extremely unlikely that what is desired or feared by an organism will

never suffer change as time goes on. This social constructionist theory thus allows for a needful

evolutionary adjustment.

A mathematical theory of perception-in-action has been devised and investigated in many

forms of controlled movement, and has been described in many different species of organism

using the General Tau Theory. According to this theory, tau information, or time-to-goal

information is the fundamental 'percept' in perception. Two types of consciousness are

considerable regarding perception: phenomenal (any occurrence that is observable and physical)

and psychological. The difference every sighted person can demonstrate to him- or herself is by

the simple opening and closing of his or her eyes: phenomenal consciousness is thought, on

average, to be predominately absent without senses such as sight. Through the full or rich

sensations present in senses such as sight, nothing by comparison is present while the senses are

not engaged, such as when the eyes are closed. Using this precept, it is understood that, in the

vast majority of cases, logical solutions are reached through simple human sensation. The

analogy of Plato's Cave was coined to express these ideas.

Passive perception (conceived by René Descartes) can be surmised as the following

sequence of events: surrounding → input (senses) → processing (brain) → output (re-action).

Although still supported by mainstream philosophers, psychologists and neurologists, this theory

is nowadays losing momentum. The theory of active perception has emerged from extensive

research of sensory illusions, most notably the works of Richard L. Gregory. This theory, which

is increasingly gaining experimental support, can be surmised as dynamic relationship between

"description" (in the brain) ↔ senses ↔ surrounding, all of which holds true to the linear

concept of experience.

Factors that Influence Perception

Cognitive Psychology & Its Applications

One of the central assumptions of the constructivist approach to perception is that

perception is not determined entirely by external stimuli. As a consequence, it is assumed that

emotional and motivational states, together with expectation and culture, may influence people’s

perceptual hypotheses and thus their visual perception. This notion that perception is influenced

by various factors is often referred to as perceptual set. This is “a perceptual bias or

predisposition or readiness to perceive particular features of a stimulus” (Allport, 1955).

Basically, it is the tendency to perceive or notice some aspects of the available sense data and

ignore others. The factors that influence perception and create perceptual set are discussed

below.

The Influence of Motivation on Perception

There are suggestions that the extent of our motivation will affect the speed and way in

which we perceive the world. For example, there are suggestions that bodily needs can influence

perception (so that food products will seem to be brighter in colour when you are hungry).

Bruner & Goodman (1947) aimed to show how motivation may influence perception. They

asked rich and poor children to estimate the sizes of coins and the poor children over-estimated

the size of every coin more than the rich children. Solley & Haigh (1948) asked 4 - 8 year olds to

draw pictures of Father Christmas at intervals during the month before Christmas and the two

weeks after Christmas. They found that as Christmas approached the pictures became larger and

so did Santa’s sack of toys! After Christmas, however, the toys shrank and so did Santa! This

suggests that motivation (higher before Christmas than after) influenced the child’s perception of

Santa and his toys making them more salient before Christmas and less salient after.

The Influence of Expectation on Perception

This is the idea that what we see is, at least to some extent, influenced by what we expect

to see. Expectation can be useful because it allows the perceiver to focus their attention on

particular aspects of the incoming sensory stimulation and helps them to know how to deal with

the selected data - how to classify it, understand it and name it. However, it can distort

perceptions too. Some experiments (e.g. Minturn & Bruner, 1951) have shown that there is an

interaction between expectation and context. Expectation affects other aspects of perception -

for example, we may fail to notice printing errors or writing errors because we are expecting to

see particular words or letters. For example - “The cat sat on the map and licked its whiskers” -

could you spot the deliberate mistake? In each case what you perceived and what was physically

present was probably different. Another classic example, which suggests that previous

experience affects perception, is Leeper’s young woman/old crone. Expectation certainly

influenced perception.

The Influence of Emotion on Perception

Many researchers suggest that our emotional state will affect the way that we perceive.

For example, there is a term “perceptual defense” (McGinnis, 1949) which refers to the effects of

emotion on perception - findings from a number of experiments show that subliminally1-

perceived words which evoke unpleasant emotions take longer to perceive at a conscious level

than neutral words. It is almost as if our perceptual system is defending us against being upset or

offended and it does this by not perceiving something as quickly as it should. McGinnis (1949)

investigated perceptual defense by presenting subjects with eleven emotionally neutral words

(such as “apple”, “broom” and “glass”) and seven emotionally arousing, taboo words (such as

“whore”, “penis”, “rape”). Each words was presented for increasingly long durations until it was

named. There was a significantly higher recognition threshold for taboo words - i.e. it took

longer for subjects to name taboo words. This suggested that perceptual defense was in operation

and that it was causing alterations in perception.

The Influence of Culture on Perception

In the Western world rooms are nearly always rectangular and many objects in our

environment have right-angled corners and sharp edges. Such things as roads and railways in our

world are common, presenting long parallel lines which seem to converge because of

perspective. In the Western world we have a visual environment rich in perspective cues to

distance. Do people in other environments where there are few right angles and few long parallel

lines see the world in the same way as we do? Are they as susceptible, for instance, to the

illusions that are said to be associated with perspective, such as the Muller-Lyer & Ponzo

illusions?

A large comparative study was carried out by Seagull et al (1963). They compared

Africans, Philippines, South Africans and Americans on various illusions. They found that with

the Muller-Lyer illusion the Africans and Philippines were much less susceptible than the other

two groups. To explain such findings, Seagull suggested the “carpentered world” hypothesis

saying “We live in a culture in which straight lines abound and in which perhaps ninety percent

of the acute and obtuse angles formed on our retina by the straight lines of our visual field are

realistically interpretable as right angles extended in space”. In other words, we tend to interpret

illusion figures such as the Muller-Lyer in terms of our past experiences.

CHAPTER 4: GESTALT PRINCIPLES AND PERCEPTUAL APPLICATIONS

Gestalt Principles

- Connection to Gestalt Psychology

Gestalt psychology attempts to understand psychological phenomena by viewing them as

organised and structured wholes rather than the sum of their constituent parts. Thus, Gestalt

psychology dissociates itself from the more 'elementistic'/reductionistic/decompositional

approaches to psychology like structuralism (with its tendency to analyse mental processes into

elementary sensations) and it accentuates concepts like emergent properties, holism, and context.

SIMILARITY

Similarity occurs when objects look similar to one another. People often perceive them as a

group or pattern. The law of similarity captures the idea that elements will be grouped

perceptually if they are similar to each other.

 

The example above (containing 11 distinct objects) appears as as single unit because all of the

shapes have similarity.

Unity occurs because the triangular shapes at the bottom of the eagle symbol  look similar to the

shapes that form the sunburst.

 

When similarity occurs, an object can be emphasized if it is dissimilar to the others. This is

called anomaly.

 

The figure on the far right becomes a focal point because it is dissimilar to the other shapes.

 

CONTINUATION

Continuation occurs when the eye is compelled to move through one object and continue to

another object.

 

Continuation occurs in the example above, because the viewer's eye will naturally follow a line

or curve. The smooth flowing crossbar of the "H" leads the eye directly to the maple leaf.

CLOSURE

Closure occurs when an object is incomplete or a space is not completely enclosed. If enough of

the shape is indicated, people perceive the whole by filling in the missing information.

Although the panda above is not complete, enough is present for the eye to complete the shape.

When the viewer's perception completes a shape, closure occurs.

PROXIMITY

Proximity occurs when elements are placed close together. They tend to be perceived as a group.

 The law of proximity posits that when we perceive a collection of objects, we will see objects

close to each other as forming a group.

The nine squares above are placed without proximity. They are perceived as separate shapes.

When the squares are given close proximity, unity occurs. While they continue to be separate

shapes, they are now perceived as one group.

SYMMETRY

The principle of symmetry is that, the symmetrical areas tend to be seen

as figures against the asymmetrical background.

SURROUNDNESS

According to this principle areas which can be seen as surrounded by others tend to be

perceived as figures. In this figure the word is initially confused by resuming the black area

as a ground.

SMALLNESS

Smaller areas tend to be seen as figures against larger background. In these figures we are

likely to see a black cross rather than a white cross

.

Similarity refers to our tendency to group things together based upon how similar to each

other they are.  In the first figure above, we tend to see two rows of red dots and two rows of

black dots.  The dots are grouped according to similar color.  In the next figure, we tend to

perceive three columns of two lines each rather than six different lines.  The lines are grouped

together because of how close they are to each other, or their proximity to one another. 

Continuity refers to our tendency to see patterns and therefore perceive things as belonging

together if they form some type of continuous pattern.  In the third figure, although merely a

series of dots, it begins to look like an "X" as we perceive the upper left side as continuing all the

way to the lower right and the lower left all the way to the upper right.  Finally, in the fourth

figure, we demonstrate closure, or our tendency to complete familiar objects that have gaps in

them.  Even at first glance, we perceive a circle and a square.

Perception in Sciences

Photographs capturing perspective are two-dimensional images that often illustrate the

illusion of depth. (This differs from a painting, which may use the physical matter of the paint to

create a real presence of convex forms and spatial depth.) Stereoscopes and View masters, as

well as 3-D movies, employ binocular vision by forcing the viewer to see two images created

from slightly different positions (points of view). By contrast, a telephoto lens—used in televised

sports, for example, to zero in on members of a stadium audience—has the opposite effect. The

viewer sees the size and detail of the scene as if it were close enough to touch, but the camera's

perspective is still derived from its actual position a hundred meters away, so background faces

and objects appear about the same size as those in the foreground.

Articles about Perception:

Perceiving affordances for joint actions

Two individuals acting together to achieve a shared goal often have an emergent set of

afforded behavioral possibilities that may not easily reduce to either acting alone. In a series of

experiments we examined the critical boundaries for transitions in behavior for individuals

walking through an aperture alone or alongside another actor as a dyad. Results from

experiment 1 indicated that an intrinsically scaled critical boundary for behavioral transitions

was different in individuals than in dyads performing a similar task. Experiment 2 demonstrated

that observers are perceptually sensitive to the difference in action parameters for the dyad, while

still maintaining perceptual sensitivity about the boundaries of action relative to individuals. In

experiment 3, we determined that observers’ perception of critical action boundaries for

individuals and dyads has a similar informational basis (eye-height scaling). In experiment 4, we

demonstrated that observers were able to perceive critical action boundaries for other dyads

independently of membership. Together, these results suggest that individuals are sensitive to the

affordances related to a joint action, and that this process may not entirely reduce to the

perception of the affordances for each individual.

Human flavor perception: Application of information integration theory

The perception of flavor arises from the combination of inputs from several sensory

modalities, especially gestation (taste proper) and olfaction (the primary source of flavor

qualities). Both the perception of intensity of suprathreshold flavorings and, notably, the

detection of weak flavorants are consistent with a rule of additives. Thus, the detectability, d′, of

mixtures of the gustatory flavorant sucrose and the olfactory flavorant vanillin approximates the

additive sum of detect abilities of the two components, within a model that assumes pooled noise

in the flavor system that derives from both modalities. When gustatory and olfactory flavorants

are presented in isolation, however, under conditions that encourage or permit selective attention

to one modality or the other, it may be possible to filter out the noise associated with the

unattended modality, and leading thereby to a rule of vector summation.

Techniques, Perception, and Applications of Time-Compressed Speech

Abstract

There are a variety of techniques for time-compressing speech that have been developed over the

last four decades. This paper consists of a review of the literature on methods for time-

compressing speech, including related perceptual studies of intelligibility and comprehension.

Considerations

There are three variables that can be studied in compressed speech [Duk74a]:

1. The type of speech material to be compressed (content, language, background noise,

etc.).

2. The process of compression (algorithm, mono or stereo presentation, etc.).

3. The listener (prior training, intelligence, listening task, etc.).

Other related factors come into play in the context of integrating speech into computer

workstations or hand-held computers:

1. Is the material familiar or self-authored, or is it unfamiliar to the listener?

2. Does the recorded material consist of many short items, or large unsegmented chunks of

speech?

Speaking Rapidly

The normal English speaking rate is between 130-200 words per minute (wpm). When speaking

fast, a talker unintentionally changes relative attributes of his speech such as pause durations,

consonant-vowel duration, etc. Talkers can only compress their speech to about 70% because of

physiological limitations  [BM76].

Speed Changing

Speed changing is analogous to playing a tape recorder at a faster (or slower) speed. This method

can be replicated digitally by changing the sampling rate during the playback of a sound. These

techniques are undesirable since they produce a frequency shift proportional to the change in

playback speed, causing a decrease in intelligibility.

Speech Synthesis

With purely synthetic speech it is possible to generate speech at a variety of word rates. Current

text-to-speech synthesizers can produce speech at rates up to 550 wpm. This is typically done by

selectively reducing the phoneme and silence durations. This technique is powerful, particularly

in aids for the disabled, but is not relevant to recorded speech.

Vocoding

Vocoders that extract pitch and voicing information can be used to time-compress speech. Most

vocoding efforts, however, have focused on bandwidth reduction rather than on naturalness and

high speech quality. The phase vocoder, described in section 7.2, is an exception.

Silence Removal

A variety of techniques can be used to find silences (pauses) in speech and remove them. The

resulting speech is ``natural, but many people find it exhausting to listen to because the speaker

never pauses for breath'' [Neu78]. The simplest methods involve the use of energy or average

magnitude measurements combined with time thresholds; other metrics include zero-crossing

rate measurements, LPC parameters, etc. A variety of speech/silence detection techniques are

reviewed. Maxemchuk used 62.5ms frames of speech corresponding to disk blocks (512 bytes of

8kHz, 8-bit -law data). For computational efficiency, only a pseudo-random sample of 32 out of

every 512 values were looked at to determine low energy portions of the signal. Several

successive frames had to be above or below a threshold in order for a silence or speech

determination to be made. TASI (Time Assigned Speech Interpolation) is used to approximately

double the capacity of existing transoceanic telephone cables [MS62]. Talkers are assigned to a

specific channel while they are speaking; the channel is then freed during silence intervals.

During busy hours, a talker will be assigned to a different channel about every other ``talkspurt''.

The TASI speech detector is necessarily a real-time device, and must be sensitive enough to

prevent clipping of the first syllable. However, if it is too sensitive, the detector will trigger on

noise and the system will operate inefficiently. The turn-on time for the TASI speech detector is

5ms, while the release time is 240ms. The newer DSI (Digital Speech Interpolation) technique is

similar, but works entirely in the digital domain. Note that Maxemchuk's system was primarily

concerned with reducing the time a listener needed to hear a message and minimizing storage

requirements. DSI/TASI are concerned with conserving network bandwidth. More sophisticated

energy and time heuristics, summarized in are used in endpoint detection for isolated word

recognition--to ensure that words are not inadvertently clipped. The algorithms for such

techniques are more complex than those mentioned above, and such fine-grained accuracy is

probably not necessarily for compressed speech or speech scanning.

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