What is Perception

• Perception is the process through which people take raw sensations from the environment and interpret them, using knowledge , experience and understanding of the world, so that the sensation become meaningful experiences.

Factors affecting perception

• Motivation• Expectation • Emotion• Culture• Past Experience

The Influence of Motivation

• The extent of our motivation will affect the speed and way in which we perceive the world.

• For example, food products will seem to be brighter in color when you are hungry.

The Influence of Expectation

• 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.

• However, it can distort perceptions too.

• For example, we may fail to notice printing errors or writing errors because we are expecting to see particular words or letters.

The Influence of Emotion

• Emotions affect our perception on a physiological level. Physiologically our current emotion could effect our perceptions by altering how the information is taken in.

• We find people with squeaky voices who speak very rapidly as extremely annoying if we are tired, but If we are in a good we probably wouldn't find them annoying.

Influence of culture• Culture plays a major role in how we

view the world, and how we take in the things around us.

• In Russia Red revolution.• In China, brides wear Red and it is

considered a Good Luck color. To most • Asians Red means happiness and

prosperity. In India Red is a symbol of life-giving purity.

• In the Middle East the color symbolism of Red is Danger and Evil.

Influence of past experience

• Past experiences can also affect perception because those experiences were being stored in the mind of an individual.

Perception and communication

• Perception and communication are related as Perception is a necessary step toward the process of communication.

• This process of perception and communication is two-fold.

• A person first communicates with him or herself based on the way he or she perceives the sensory data from different senses through a process known as intrapersonal communication.

• In terms of interpersonal communication, perception and communication are linked in the various ways that perception guides the way people relate and communicate with each other.

Perception affects communication

• In any type of communication there is always the chance that the intended meaning is lost in the communication.

• Robert L. Scott, a communication scholar said that "Nothing is clear in and of itself but in some context for some person."

• Everybody perceives things differently. That does not mean that one person is right and the other wrong.

Perception And Psychology

Perception in Psychology• In order to receive information from the

environment we are equipped with sense organs e.g. eye, ear, nose.

• Each sense organ is part of a sensory system which receives sensory inputs and transmits sensory information to the brain

• There are several theories that psychologists have that show us how we perceive the world. These theories (except bottom-up and top down) are not in opposition to each other.

• A major theoretical issue on which psychologists are divided is the extent to which perception relies directly on the information present in the stimulus.

• This controversy is discussed with respect to Gibson (1966) who has proposed a direct theory of perception which is a 'bottom-up' theory, and Gregory (1970) who has proposed a constructivist (indirect) theory of perception which is a 'top-down' theory.

Gibson’s 'bottom-up' theory

• Gibson argues that there is enough information in our environment to make sense of the world in a direct way.

• As we move through our environment, objects which are close to us pass us by faster than those further away.

Evidence to Support Gibson’s Theory:

• ‘Light and the Environment• Changes in the flow of the

optic array contains important information about what type of movement is taking place.

• Gibson claims that the center of that movement indicates the direction in which the perceiver is moving.

• ‘The Role of Invariants in Perception’

• Gibson notes that we rarely see a static view of an object or scene. When we move our head and eyes or walk around our environment, things move in and out of our viewing fields.

• Two good examples of invariants are texture and linear perspective.

• Affordances’• Affordances are cues in the environment that

aid perception. Important cues in the environment include:

• Optical Array• Relative Brightness• Texture Gradient• Relative Size • Superimposition

Evidence against Gibson’s Theory:

• Gibson’s theory of perception provides an explanation for fast accurate perception, however he fails to explain why perceptions are sometimes incorrect.

• Gibson’s theory fails to explain naturally occurring ‘illusions’.

• One of the weakest aspects of Gibson’s theory is the concept of affordances. Humans live within a particular cultural context in which knowledge about the use of objects is learned rather than ‘afforded’.

Gregory’s Top-Down Theory of Perception

• Gregory sees perception as a hypothesis – he argues that formation of incorrect hypotheses will lead to errors in perception

• Gregory notes that a lot of information reaches the eyes but is lost by the time it reaches the brain (about 90% is lost).

Evidence to Support Gregory’s Theory:

• ‘Perception allows behavior to be generally appropriate to non-sensed object characteristics’.

• For example, we respond to certain objects as though they are doors even though we can only see a long narrow rectangle as the door is ajar.

• Perceptions can be interpreted• if you stare at a cross on the cube

the orientation can suddenly change or ‘flip’, then one pattern produces two perceptions.

• Gregory argues that this occurs because the brain develops two equally reasonable hypotheses and is unable to decide between the two.

• highly unlikely objects tend to be mistaken for likely objects

• Gregory tested this with a hollow mask he argues that although the audience was aware

• The mask was hollow (they were aware of the environment) they were still tricked by the visual illusion.

Evidence against Gregory’s Theory:

• The Nature of perceptual hypotheses’ If perceptions make use of hypothesis testing

the question can be asked ‘what kind of hypotheses are they?

• ‘Perceptual development’ If we all have to construct our own worlds

based on past experiences why are our perceptions so similar, even across cultures

• ‘Sensory Evidence’ The main criticism of Gregory’s theory is that

his evidence is not ecologically valid. The stimulus’ that he uses is artificial and does not apply to the real world. Gibson argues that his theory is more realistic because he uses real world application.

Signal Detection Theory

• This theory examines how outside influences effect our perception.

• For example, if I am really hungry for meat, I am more likely to smell a burger than if I was not. If I think I smell a burger, but it is not really there, that is called a false positive (perceiving stimuli that is not there).

Absolute Threshold

• Thresholds are the idea that our senses have limits.

• First there is the absolute threshold, which is the smallest amount you can just sense something.

• For example, If you can just barely hear a sound- then it is at your absolute threshold for sound.

Difference threshold

• Another type of threshold is called the difference threshold.

• The difference threshold the smallest amount of change needed in a stimulus before we notice the change.

• If you are watching T.V and someone is singing any song in the next room. You grab the controller and raise the volume one bar.

• That change in volume was under your difference threshold.

Visual Constancy

• Our eyes are like mirrors, reflecting information to the back of our retinas.

• Objects that are closer to us produce bigger images on our retinas.

Shape Constancy

• Objects viewed from different angles will produce different shapes on our retinas, but we know that the shape of the object remains constant.

Brightness Constancy

• We perceive objects as being a constant color even as the light reflecting off the object changes.

• A white piece of paper indoors reflects considerably less light than does a black lump of coal outside on a bright, sunny day. Yet the paper looks white, and the coal black.

Depth Cues

• The concept of depth is one of the most studied aspects of perception.

• Researcher E.J. Gibson conducted a very famous experiment called the visual cliff experiment to determine when humans are able to see depth.

Types of perception

Amodal Perception

• Amodal perception is one of the most recognizable types of perception in psychology.

• It is the observation and interpretation of things in terms of depth and motion.

Color Perception

• Color perception, on the other hand, describes the way the visual senses, denoting the eyes, observe hues and contextualize them in the environment.

Speech Perception

• The other types of perception in psychology include those that interpret verbal output.

• Speech perception, for one, helps in not only understanding one another, but deducing meaning from mere sound.

Depth Perception

• Depth perception also acts as one of the types of perception psychology

• It is the visual ability to judge the relative distance of objects and the spatial relationship of objects at different distances.

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