Topic 1: Introduction to Perception

Question 1

In what terms can perception be described in?

Answer 1

can be defined in terms of sensory processes, like receptor activation and neural firing

or in terms of mental activity that mediates between sensation and awareness, interpreting what our senses tell us (subjective experience)

Question 2

What is the definition of sensation?

Answer 2

process of encoding energy or chemicals in the environment in terms of neural signals

a basic experience elicited by a simple stimulus

more concerned with your own physical experience (ego centric)

e.g. feeling of warmth on your skin

Question 3

What is the definition of perception?

Answer 3

organization and interpretation of neural signals, making them meaningful

more complex conscious experiences produced by integrating sensations

more concerned with identifying the stimulus

e.g. you see a glowing red stove element, producing heat you feel; you know it is 50 cm away, and it can burn you

Question 4

Why do we study perception for understanding?

Answer 4

to determine how underlying mechanisms function

first step in understanding cognition (e.g. mind-body relationship)

to know why the world looks. sounds, feels, tastes, and smells the way it does

Question 5

Why do we study perception to solve practical problems?

Answer 5

to develop solutions for the sensory impaired (e.g. Braille, glasses)

to understand the practical applications of illusions

to produce substitutes for the world (e.g., stereo sound, surround sound)

to produce substitutes for the observer (e.g. robotic vision)

Question 6

What is the central problem in perception?

Answer 6

the world is three-dimensional
the image on our retina is 2-D
yet we think of the world in 3-D

this problem is called underdetermination

Question 7

What is a distal stimulus?

Answer 7

the object in the world

e.g. an apple, a finger poking your arm, a vibrating string

Question 8

What is a proximal stimulus?

Answer 8

the pattern of energy or chemicals impinging on our receptors

e.g. pattern of photons on your retina; kinetic energy on your skin; sound energy hitting your eardrum

Question 9

How do we go from an underdetermined proximal stimulus produced by a distal stimulus, and arrive at a correct perception of the world?

Answer 9

not enough info in the proximal stimulus at our sensors to tell you what a distal stimulus actually is

2-D retinal image of an apple –> percept of 3-D apple

there are many possible interpretations of the proximal stimulus

different answers to this question define different schools of thought in the study of perception

Question 10

What is structuralism?

Answer 10

goals: analyze conscious processes into basic “elements”; specify how elements become connected

Wilhelm Wundt: first psychology lab

Edward Titchener relied on introspection: analysis of one’s own conscious experience

Question 11

What is the problem with structuralism?

Answer 11

perception is holistic, not elemental

can’t break down your conscious experience

Question 12

What is Gestalt psychology?

Answer 12

opposed structuralism: decomposition to elementary components loses information

was a holistic approach that emphasized consciousness

goal: specify the relationship among stimuli

motto: “the whole is different than the sum of its parts”

founded by Max Wertheimer

Question 13

What is constructivism?

Answer 13

perceiving is an active process, affected by our knowledge and experience

we must interpret ambiguous information provided by the environment

computations over internal representations yield percepts

Hermann von Helmholtz, Irvin Rock, Richard Gregory

Question 14

What is the ecological approach?

Answer 14

we should study perception in natural settings

enough information is available in the environment to make mental calculations unnecessary

J.J. Gibson: proposed information is directly picked up from the government

Question 15

What is the computational approach?

Answer 15

assumes the mind is an information processor that receives, stores, retrieves, transforms, and transmits information

David Marr: defined vision mathematically, using computer simulations

information processing has three levels of analysis: computational theory, representation and algorithm, and hardware implementation

Question 16

What is computational theory?

Answer 16

what is the system doing?

e.g. what does it mean to “see” something?

Question 17

What is representation and algorithm?

Answer 17

what is the percept? how is it being processed?

e.g. do the eyes function like cameras? is there an “inner screen” in our heads?

Question 18

What is hardware implementation?

Answer 18

what physical “machinery” does this?

e.g. what neural circuits allow us to see?

Question 19

What is the neurophysiological approach?

Answer 19

based on reductionism: understanding of behavior via studying the underlying biological processes

important for sensation, less effective for perception

Question 20

Perception

Answer 20

the experiences that result from stimulation of the senses

Question 21

Sensation

Answer 21

often identified with elementary processes that occur at the beginning of a sensory system

Question 22

Perceptual Process

Answer 22

a sequence of steps leading from the environment to perception of a stimulus, and action with regard to the stimulus

Question 23

Distal Stimulus

Answer 23

the stimulus “out there”, in the external environment

Question 24

Proximal Stimulus

Answer 24

the stimulus on the receptors

in vision, this would be the image on the retina

Question 25

Ciple of Transformation

Answer 25

stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception

Question 26

Principle of Representation

Answer 26

everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous systems

Question 27

Transduction

Answer 27

the transformation of environmental energy to electrical energy

Question 27

Neural Processing

Answer 27

operations that transform electrical signals within a network of neurons or that transform the response of individual neurons

Question 27

Sensory Receptors

Answer 27

cells specialized to respond to environmental energy, with each sensory system’s receptors specialized to respond to a specific type of energy

Question 27

Cerebral Cortex

Answer 27

the 2-mm-thick layer that covers the surface of the brain and contains the machinery for creating perception, as well as for other functions, such as language, memory, and thinking

Question 27

Visual Form Agnosia

Answer 27

an inability to recognize objects

Question 27

Primary Receiving Area

Answer 27

area of the cerebral cortex that first receives most of the signals initiated by a sense’s receptors

for example, the occipital cortex is the site of the primary receiving area for vision, and the temporal lobe is the site of the primary receiving area for hearing

Question 27

Knowledge

Answer 27

any information that the perceiver brings to a situation, such as prior experience or expectations

Question 28

Bottom-Up Processing

Answer 28

processing that is based on the information on the receptors

also called data-based processing

Question 29

Top-Down Processing

Answer 29

processing that starts with the analysis of high-level information, such as knowledge a person brings to a situation

also called knowledge-based processing

Question 30

Stimulus-Behavior Relationship

Answer 30

the relationship between stimuli and behavioral responses, where behavioral responses can be perception, recognition, or action

Question 31

Psychophysics

Answer 31

measures the relationships between the physical (stimulus) and the psychological (behavioral responses)

Question 32

Grating Acuity

Answer 32

the narrowest spacing of a grooved surface on the skin for which orientation can be accurately judged

Question 33

Stimuli-Physiology Relationship

Answer 33

the relationship between stimuli and physiological responses

Question 34

Physiology-Behavior Relationship

Answer 34

relationship between physiological responses and behavioral responses

Question 35

Absolute Threshold

Answer 35

the smallest stimulus level that can just be detected

Question 36

Threshold

Answer 36

the minimum stimulus energy necessary for an observer to detect a stimulus

Question 37

Classical Psychophysical Methods

Answer 37

the methods of limits, adjustment, and constant stimuli. described by Fechner, that are used for measuring thresholds

Question 38

Difference Threshold

Answer 38

the smallest difference between two stimuli that enables us to tell the difference between them

Question 39

Magnitude Estimation

Answer 39

a psychophysical method in which the subject assigns numbers to a stimulus that are proportional to the subjective magnitude of the stimulus

Question 40

Perceived Magnitude

Answer 40

a perceptual measure of stimuli, such as light or sound, that indicates the magnitude of experience

Question 41

Reaction Time

Answer 41

the time between presentation of a stimulus and the person’s reaction to it

Question 42

Phenomenological Report

Answer 42

method of determining the relationship between stimuli and perception in which teh observer described what he or she perceives

Question 43

Electromagnetic Spectrum

Answer 43

continuum of electromagnetic energy that extends from very-short-wavelength gamma rays to long wavelength radio waves

visible light is a narrow band within this spectrum