Lesson 1: INTRODUCTION TO
PSYCHOLOGY
PSYCHOLOGY
 It is the scientific study of thought, behavior
and mental processes.
 The systematic study of behavior and
experience
 Behavior : overt/outward action and
reactions.
 Mental Processes : internal, covert activity
of our minds.
root word psyche is a Greek word for “soul” or
“mind,” logos means “word”
modern psychology is as likely to study the brain
and behavior as it is the “mind.”

both a clinical practice and a science.
 clinical practice side encompasses the
services provided in therapists’ offices,
schools, hospitals, and businesses.
GOALS OF PSYCHOLOGY
Describe - the different ways that organism behave
Explain - the causes of behavior
Predict - how organisms will behave in certain
situations
Developmental Psychology
o The study of how thought and behavior
change and remain stable across the life
span.
o explores how thought and behavior change
and show stability across the lifespan.
o allows us to appreciate that organisms –
human or otherwise – change and grow.
Developmental psychologists ask questions like:
“How do our reasoning skills or emotional skills
change as we age? Does old age bring wisdom?”
Biological Psychology
o The study of the relationship between
bodily systems and chemicals and how
they influence behavior and thought.
o includes research on all areas of
connection between bodily systems and
chemicals and their relationship to
behavior and thought.
Research about stress and health, studying the
effects of stress on hormones and behavior is an
example of research in this field.
It is an older term that is being replaced by
behavioral
neuroscience
in
contemporary
psychology.
Control - an organism’s behavior positively, or
negatively
SUBDISCIPLINES OF PSYCHOLOGY
Psychology is divided into various areas of
investigation.
 The field of psychology is divided into
more than 25 distinct, but increasingly
interrelated, subdisciplines.
Cognitive Psychology
o study of how we perceive information,
how we learn and remember, how we
acquire and use language, and how we
solve problems.
o The study of how people perceive,
remember, think, speak, and solve
problems.
a researcher who is concerned with how people
remember their new mobile number is studying
cognitive psychology.
Experimental Psychology
o Deals with research studies on cognition
and learning
experiments are conducted in laboratory to address
their research questions.
Personality Psychology
o The study of what makes people unique
and the consistencies in people’s behavior
across time and situations.
o considers what makes people unique, as
well as the consistencies in people’s
behavior across time and situations.
A question from this area, for example, might be
whether the tendency to be friendly, anxious, or
hostile affects one’s health, career choice, or
interpersonal relationships.
Social Psychology
o The study of how living among others
influences thought, feeling, and behavior.
o considers how real or imagined presence of
others influences thought, feeling, and
behavior.
Social psychologists ask questions like: How does
the presence of other people change an
individual’s thoughts, feelings, or perceptions?
Why are we attracted to particular kinds of
people?
Clinical Psychology
o The diagnosis and treatment of mental,
emotional, and behavioral disorders and
the promotion of psychological health.
o focuses on the diagnosis and treatment of
mental, emotional, and behavioral
disorders; and
o ways to promote psychological health.
Clinical psychologists also conduct research and
teach, and they work in universities, medical
settings, or private practice.
Counseling Psychology
o deals with less severe psychological
disorders.
Counseling psychologists treat and assess relatively
healthy people and assist them with career and
vocational interest.
Health Psychology
o The study of the role psychological factors
play in regard to health and illness.
o examines the role of psychological factors
in physical health and illness.
Topics in this area range from studies of how
stress is linked to illness and immune function to
studies on the role of social factors in how people
interact with health care professionals.
Educational Psychology
o The study of how students learn, the
effectiveness of particular teaching
techniques, the social psychology of
schools, and the psychology of teaching.
o studies how students learn, the
effectiveness of particular teaching
techniques, the social psychology of
schools, and the psychology of teaching.
attempts to understand special population of
students such as the academically gifted and those
with special needs.
Industrial/Organizational (IO) Psychology
o The application of psychological concepts
and questions to work settings.
o It is an applied science that involves
understanding real-world rather than
laboratory behavior(Aamodt, 2010)..
Industrial side: involves matching employees to
their jobs and uses psychological principles and
methods to select employees and evaluate job
performance.
Organizational side: aims to make workers more
productive and satisfied by considering how work
environments and management styles influence
work motivation, satisfaction, and productivity.
Sports Psychology
o The study of psychological factors in
sports and exercise.
o It examines the psychological factors that
affect performance and participation in
sports and exercise.
sports psychologists might focus on improving
athletic performance through techniques as
relaxation and visualization.
Forensic Psychology
o a blend of psychology, criminal justice,
and the law (Adler, 2004).
Forensic psychologists make legal evaluations of a
person’s mental competency to stand trial, the
state of mind of a defendant at the time of a
crime, the fitness of a parent to have custody of
children, and allegations of child abuse.
They also do criminal profiling to identified who
might have committed a particular crime
Brief History of Psychology
Prehistoric views
 is the period where humans tried to cure one
another
 they have shamans as their “doctors” ; and
 they believe that a person with mental illness is
possessed by evil spirits kaya nagpe-perform
sila ng exorcism, incantations, and prayers
 Trephination is drilling a small hole
in a person’ skull
Ancient Views
 period where people moved away from
supernatural explanations to natural and
physiological explanations (Tseng, 1973).
 made connections between a person’s
bodily organs and emotions
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
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The heart housed the mind; the liver for
the spiritual soul; the lung for the animal
soul; the spleen for ideas and intelligence;
and the kidneys for will and vitality.
Ancient Egyptians apparently used
narcotics to treat pain
Greek physician Hippocrates (460–377
BCE) was the first to write about a man
suffering from a phobia of heights—now
called acrophobia.
Medieval views
 attributed the psychological disorders to
natural causes as people were thought to
be possessed by demons, spirits, and the
devil – not by physical disorders
 In this period, asylums were established to
house the mentally ill.
Modern views
 consider psychological disorders as illness
and that they should be treated as medical
conditions, with appropriate diagnosis and
therapy.
 period when Emil Kraepelin, a German
psychiatrist collected data on various kinds
of psychological disorders and began
systematically classifying and diagnosing
them.
 Other views of psychological disorders
and psychotherapy approaches have
emerged in this period namely:
psychoanalysis, drug therapy, and modern
criteria for diagnosing mental disorders.
Brief History of Scientific Psychology
Philosophy of Empiricism
o It is the view that all knowledge and
thoughts come from experience.
o John Locke, an English philosopher
argued that the mind begins as a tabula
rasa, or blank slate, onto which experience
writes the contents of the mind
Psychophysics of Human Perception
o Psychology of physical sensations
o study of how people experience physical
stimuli such as sound, light, waves, and
touch.
o One important principle here is that the
perception of physical properties is not the
same as the physical properties themselves.
Structuralism (Wilhelm Wundt)
o Breaking down experience into its
elemental parts offered the best way to
understand thought and behavior.
o Structuralists believed that a detailed
analysis of experience as it happened
provided the most accurate glimpse into
the workings of the human mind.
o Introspection – a method they use to look
into one’s own mind for the information
about the nature of consciousness and
experience.
Functionalism (William James)
o Argued that it was better to look at why
the mind works the way it does that to
describe its parts.
o Also relied on introspection as a primary
method of understanding how the mind
worked.
Behaviorism (John Watson)
o Psychology can be a true science only if it
examines observable behavior, not ideas,
thoughts, feelings, or motives.
Humanistic and Positive Psychology (Martin
Seligman & Mihaly Csikszentmihalyi)
o Humanistic psychology is a theory of
psychology that focuses on personal
growth and meaning as a way of reaching
one’s highest potential.
o Positive psychology is a scientific
approach to studying, understanding, and
promoting
healthy
and
positive
psychological functioning.
Gestalt Psychology (Max Wertheimer)
o Perception occurs in unified wholes, where
the whole is more than the sum of its
parts.
o Your ability to perceive something in
more than one way
Behavioral Genetics, Behavioral Neuroscience, and
Evolutionary Psychology
o Who we are and what we do and think are
very much influenced by genetic factors,
and brain activity, with a long evolutionary
past.
Psychology Then:
1.
-
2.
3.
4.
5.
-
Structuralism (Edward Titchener)
Experience could be broken down into
individual, emotions & sensation.
(structure)(parts)
Functionalism (William James)
How people functions in the real world
Gestalt Psychology (Max Wertheimer)
only be understood as a whole, entire
event
Psychoanalysis (Sigmund Freud)
Early life experiences; role of
unconscious, development through stages
Behaviorism (John B. Watson)
Observable and ignore “consciousness”
Psychology Now:
1.
2.
-
3.
4.
5.
6.
-
Psychodynamic (Freud’s Theory)
Less test (conscious/complex) of
unconscious EX. Hypnotheraphy
Behavioral (Watson ??)
How behavioral responses are
learned through classical
conditioning
Humanistic (Rogers & Maslow)
Potential, free-will, self-satisfaction
Cognitive
Memory, Intelligence, social culture
Individual or group as part of a
larger group
Biophyscial
Human behavior as a result of event
in the body.
Evolutionary
Biological basis influences
LESSON 2: BIOLOGICAL BASIS OF
BEHAVIOR: THE NERVOUS SYSTEM
GENES AND BEHAVIOR
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
DNA (deoxyribonucleic acid): a large
molecule that contains the genetic material
and is passed down in the form of
chromosomes from both parents.
Chromosome: a very long thread of DNA
wrapped around proteins that hold it all
together. A normal individual has a total
of 46 chromosomes (23 chromosomes
from one parent, and another 23 from the
other parent) or 23 pairs.
Taggart, 2004), one of which you inherit
from your mother and the one from your
father.
o Dominant Alleles: are those that
show their effect even if there is
only one allele for that trait in
the pair.
o Recessive Alleles: are those that
show their effects only when
both alleles are the same.
PRINCIPLES OF BEHAVIORAL GENETICS
Behavioral genetics - is the scientific study of the
role of heredity in behavior.
First: The Connection Between Genes and Behavior
is Complex.
Genes seldom make behavior a certainty. For
example, no single gene causes anxiety. Both genetic
and environmental factors make anxiety more likely
to trouble some people than others.
Second: The Relative Effects of Genes and
Environment Can Be Teased Apart
Heritability is the extent to which a characteristic is
influenced by genetics. Identifying genetic and
environmental influences can be done through
special techniques: twin-adoption studies and geneby-environment studies.
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
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Genome: the total amount of unique
DNA.
Genotype: the entire genetic makeup of an
organism.
Phenotype: an organism’s observed
characteristics.
Genes: small segments of DNA that
contain information for producing
proteins.
+ are instructions that dictate how a
person’s body is made, in the same way
that blueprints are instructions to build a
house.
+ can carry instructions that can make it
more likely for you to develop certain
illnesses or conditions.
Polygenic: the process by which many
genes interact to create a single
characteristic such as height, weight,
personality, intelligence, etc.
Monogenic: the hereditary passing on of
traits determined by a single gene.
Mutation: a random change in genetic
sequence.
Alleles: are the different forms of a gene
(Clark & Grunstein, 2000; Starr &
Third: The Environment Can Change Gene
Expression
Epigenetics is the study of changes in the way genes
are expressed – without changing the sequence of
DNA (Meaney, 2010; Plomin et al., 2013). Some
substances that we eat, drink, or get exposed to
result in molecules attaching to certain base pairs of
genes.
NERVOUS SYSTEM
 This system controls all the actions and
automatic processes of the body
Peripheral
Nervous System
Nervous System
Central
Nervous System
Somatic
Nervous System
Autonomic
Nervous System


Information travels within a neuron in the form
of an electrical signal by action potentials
Information is transmitted between neurons by
means of chemicals called neurotransmitters
Sympathetic
Nervous System
Parasympatheti
c nervous
systems
Central Nervous System (CNS)
 it comprises the brain and the spinal cord.
Peripheral Nervous System
 consists of all the other nerve cells in the body.
 It includes the somatic nervous system and the
autonomic nervous system
Somatic Nervous System
 serves as the skeletal muscles of the body.
Soma: the cell body of the neuron and contains the
nucleus
Autonomic Nervous System (ANS)
 serves as the involuntary systems of the body,
such as the internal organs and glands
 the structures it serves control bodily processes
over which we have little conscious control,
such as changes in heart rate and blood
pressure.
Axon: a long projection that extends from a neuron’s
soma. It transmits electrical impulses toward the
adjacent neuron and stimulates the release of the
neurotransmitter.
Sympathetic Nervous System
 it activates bodily systems in times of
emergency by increasing the heart rate, dilating
the pupils of the eyes, or inhibiting digestion
Myelin Sheath: the fatty substance wrapped around
some axons, which insulates the axon, making the
nerve impulse travel more efficiently.
Parasympathetic Nervous System
 responsible for relaxation, returning the body to
a less active, restful state
Glial Cells
 provides structural support for the CNS and
the removal of cellular debris
 produce myelin
 may play an important role in neuronal
regeneration repair after brain injury
Neurons
 cells that processes and transmit info
throughout the nervous system
 there are more than 10 billion neurons in the
brain
 building blocks of the nervous system
 All the major structures of the brain are
composed of neurons
Dendrites: these are finger-like projections that
receive incoming messages from other neurons.
Synapse: the junction between the axon and the
adjacent neuron. This is where the information is
transmitted from one neuron to another.
Terminal Button: a little knob at the end of the axon
that contains tiny sacs of neurotransmitters.
Nodes of Ranvier: these are the gaps in the myelin
sheath across which the action potential jumps.
TYPES OF NEURONS
 SENSORY NEURONS
 MOTOR NEURONS
o MIRROR NEURONS
 INTERNEURONS
NEURAL TRANSMISSON
- contains a two-step process: action
potential, and neurotransmission
SUMMARY OF STEPS IN NEURAL
TRANSMISSION
 information in neural transmission always
travels in one direction;
 in the neuron – from the dendrites to the soma
to the axon to the synapses
 dendrites receive a message from other neurons
then the electrical or chemical impulse in
integrated in the soma
 if excitatory messages pass the threshold
intensity, an action potential will occur, sending
the nerve impulse down the axon
 If the inhibitory messages win out, the
likelihood that the postsynaptic neuron will fire
goes down
 nerve impulse, known as the action potential,
travels down the axon, jumping from one space
in the axon’s myelin sheath to the next, because
channels are opening and closing in the axon’s
membrane. Ions pass in and out of the
membrane
 neurotransmitters are released into the space
between neurons, known as the synaptic cleft.
Neurotransmitters released by the presynaptic
neuron then bind with receptors in the
membrane of the postsynaptic neuron
 This binding of neurotransmitter to receptor
creates electrical changes in the postsynaptic
neuron’s cell membrane, at its dendrites. Some
neurotransmitters tend to be excitatory and
increase the likelihood of an action potential.
Others tend to be inhibitory and decrease the
likelihood of an action potential
 The transmission process is repeated in
postsynaptic neurons, which now become presynaptic neurons
LESSON 3 : THE BRAIN
EVOLUTION OF HUMAN BRAIN
 First primates lived around 55 million years
ago
 Primates have relatively large amount of brain
cortex, allowing more complex thinking and
problem solving
 earliest ancestors of humans appeared in Africa
about 6 million years ago.
 Modern human brain took up to 100 years to
become fully wired and complex
AUSTRALOPHITECUS
 4 million years ago
 Brain capacity: 450-650 cc
HOMO ERECTUS
 1.5 mil to 100,000 years ago
 900 c c
NEANDERTHAL
 350,000 TO 28,000 years ago
 1450 cc
HOMO SAPIENS
 200,000 to present
 1300 cc
OVERVIEW OF THE BRAIN
Hindbrain
 earliest to develop
 this is considered as the oldest brain region
which is directly connected to the spinal cord
 Its structures regulate breathing, heart rate,
arousal, and other basic functions of survival
 The three main parts of the hindbrain includes:
the medulla, the pons, and the cerebellum.
o Medulla: a brain structure that
extends directly from the spinal cord.
It regulates breathing, heart rate, and
blood pressure.
o
o
Pons: it serves as a bridge between
lower brain regions and higher
midbrain and forebrain activity
Cerebellum: it is involved in body
movement, balance, coordination,
fine-tuning motor skills, and
cognitive activities such as learning
and language
Midbrain
 the smallest of all three major areas
 control the eye muscles, process auditory and
visual information, and initiate voluntary
movement of the body
 The midbrain, the medulla, and the pons are
sometimes referred to as brain stem
o Colliculi serves as a main auditory
(sound) center for the body
o Tegmentum motor center that relays
inhibitory signals to the thalamus and
basal nuclei to prevent unwanted
body movement
o Cerebral Peduncles main highway for
signals that need to be transported
from the cortex to other parts of the
central nervous system (CNS), and
are especially important for body
coordination
Forebrain
 last major region to evolve and was the largest
part of the human brain
 consists of the cerebrum and numerous other
structures including the thalamus, and the
limbic system
 control cognitive, sensory, and motor function
and regulate temperature, reproductive
functions, eating, sleeping, and the display of
emotions
o Thalamus receives input from the
sensory organs and relays the sensory
information to the part of the
cerebral cortex most responsible for
processing that specific kind of
sensory information. thalamus is
often called a sensory relay station. It
is surrounded by basal ganglia that
are involved in voluntary motor
control.
o Limbic System is a group of forebrain
structures that share important
functions in emotion, memory, and
motivation, including the
hypothalamus, hippocampus,
amygdala, and the cingulate gyrus
Hypothalamus
o controls the pituitary gland, which is
responsible for producing and controlling
the hormones our bodies produce.
o regulates almost all of our major drives
and motives, including hunger, thirst,
temperature, and sexual behavior
o regulates autonomic nervous system,
sympathetic system, endocrine system
Hippocampus
o Sensory information is transmitted here
o vital role in learning and memory
o gumagawa ng core memory
o memory consolidation
o special navigation
Amygdala
o almond-shaped structure directly in front
of the hippocampus
o key role in determining the emotional
significance of stimuli;
o connects with many other areas of the
brain, including the structures involved in
emotion and memory
o “emotional center”
o controls our emotional behavior
Cingulate Gyrus
o beltlike structure in the middle of the
brain
o important role in attention and cognitive
control
o “helps regulate emotions and pain”
o this area seems to malfunction in people
with schizophrenia, who have major
difficulties in focusing their attention
THE CEREBRUM CORTEX AND CEREBRAL
CORTEX
Cerebrum
 uppermost portion of the brain
 folded into convolutions (gyrus and sulcus) and
divided into two large hemispheres, the left and
the right cerebral hemispheres
o Frontal Lobes – attention, problemsolving, planning, abstract thinking,
control impulses, creativity, & social
awareness
o
o
o
Parietal Lobes – important in the
sensation and perception of touch.
Frontmost portion – somatosensory cortex
activated when different parts of the body
are touched. Behind the motor cortex of
the frontal lobe
Temporal Lobes - lie directly below the
frontal and parietal loves and right behind
the ears - main one is hearing. It houses
the auditory cortex, where sound
information arrives from the thalamus for
processing. Also connects with the
hippocampus and amygdale
Occipital Lobes - occupies the rear of the
brain. Optic nerve travels from the eye to
the thalamus and then to the occipital
lobes – specifically, to primary visual
cortex. Visual information is processed in
the visual cortex, where we “see” and
“imagine.”
Cerebral cortex
 outer layer of the brain
 very thin layer of the brain that much of human
thought, planning, reception, and consciousness
takes place
 the site of all brain activity that makes us most
human
Insula
 small structure deep inside the cerebrum
 separates the temporal lobe from the parietal
lobe
 active in the perception of bodily sensation,
emotional states, empathy, and addictive
behavior
 key role in our awareness of our bodies as our
own
 it may play a key role impulsive behavior and
may be crucial for understanding the
compulsions underlying many addictions
Cerebral Hemispheres
 divides the cerebrum into equal parts
 left hemisphere processes information in a more
focused and analytic manner
 whereas the right hemisphere integrates
information in a more holistic, or broader
manner
o Corpus callosum is the thick band of
nerve fibers connecting the two
hemispheres
BRAIN PLASTICITY AND NEUROGENESIS
Neuroplasticity
 Moldable
 Functional and structural
 brain’s ability to adopt to situations or new
functions without changing it organically
 woman’s brain is most plastic during
reproduction – a flexibility that appears to
benefit the baby
4 Principles of Neuroplasticity
1. First and most generally, neuroplasticity is the
brain’s ability to adopt new functions, reorganize
itself, or make new neural connections throughout
life, as a function of experience.
2. Almost every major structure of the neuron is
capable of experience-based change.
3. Not all regions of the brain are equally plastic.
4. Brain plasticity varies with age, being strongest in
infancy and early childhood and gradually decreasing
with age.
Neurogenesis – the process of developing new
neurons.
Arborization – the growth and formation of new
dendrites – branchlike of a tree.
Synaptogenesis – the formation of entirely new
synapses or connections with other neurons – the
basis of learning (Yates, 2016). It is probably the
best-known example of neuroplasticity
LESSON 4: SENSATION AND PERCEPTION
PART 1
Sense organs transform information from its
physical form (light or sound waves or chemicals)
 nerve impulse and transmit it  the brain, which
organizes in an instant without effort on our part.
Sensation
- it is the stimulation of our sense organs by
the outer world
Eyes are sensitive to light waves, ears to sounds,
skin to touch and pressure, tongues to tastes,
and noses to odors.
Perception
- the act of organizing and interpreting
sensory experience.
- It is how we perceive our physical world
with our utak or psychological world.
The outside world can never be directly sensed,
but rather is filtered through our particular
sense organs (sensation) and then interpreted
and given meaning in our brain (perception).
BASIC SENSORY PROCESSES
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Sensory Adaptation
- a process wherein our sensitivity
diminishes when we have constant
stimulation
Transduction
- the conversion of physical into neural
information
PRINCIPLES OF PERCEPTION
Psychophysics is how we psychologically
perceive physical stimuli such as light, sound
waves ,and touch.
Principle 1. Absolute Threshold
 It is the lowest level of a stimulus we can detect
half of the time.
 People differ in their absolute thresholds with
some people being more sensitive than others.
 Absolute thresholds are not constant
Principle 2. Signal Detection Theory
 It attempts to separate “signal” from “noise”
and takes into account both stimulus intensity
and the decision-making processes people use
in detecting a stimulus.
 Decision-making with uncertainty
 it is assumed that a person’s absolute threshold
fluctuates, sometimes being more sensitive and
other times being less sensitive, depending on
the cost of failing to detect the stimulus.
Principle 3. Difference Threshold
 It is the smallest amount of change between
two stimuli that a person can detect half of the
time.
 are relative thresholds and are also referred to a
just noticeable differences (JND) because they
involve the smallest difference that is noticeable
– and people differ in their JND sensitivity.
Principle 4. Perceptual Set
 It is the effect of frame of mind on perception.
 a tendency to perceive stimuli from a particular
frame of reference
 makes us more likely to perceive one thing than
another and explains the adage “we see what we
want to see and hear what we want to hear.”
VISION
Mammals rely on smell over all other senses, but
humans are predominantly visual creatures. We rely
so much on our sense of sight that we often ignore
other types of information.
Sensing Visual Stimuli
 The eye bends light convert energy to neural
energy and sends that information to the brain
for further processing.
 visual perception happens in the brain, with
input from the eye.
Parts of the Eye
1. Cornea – a hard covering that protects the lens.
2. Pupil – the opening in the iris.
3. Iris – the muscle that form the colored part of
the eye.
4. Lens – the structure that sits behind the pupil.
5. Retina – a thin layer of nerve tissue that lines
the back of the eye. Contains two
photoreceptors: rods for night vision and cones
for color vision or bright light.
6. Fovea – a spot on the back of the retina which
contains the highest concentration of cones in
The deepest layer of cells, where processing of light
energy begins, is made up of photoreceptors which
have two types: the rods and the cones which
convert light energy into neural impulses.
Visual Acuity – our ability to see clearly, and it is
dependent on our cones.
Vision and the Brain
1. After transduction at the photoreceptor layer,
visual information is processed by different
layers of the cells in the retina. One of these
layers is made up of the ganglion cells, the
axons of which make up the optic nerve.
2. The optic nerve transmits signals from the eye
to the brain – to the thalamus specifically, and
ultimately;
3. to the visual cortex of the occipital lobes.
This journey is not straightforward. The
information from the left visual field is processed in
the brain’s right hemisphere, and the information
from the right visual field is processed in the brain’s
left hemisphere.
Blind Spot - the point at which the optic nerve exits
the eye because this location has no receptor cells
and nothing is seen
Three Types of Neurons in the Visual Cortex
the retina.
How does light travel to the eye and how does it
convert light energy to neural energy?
1.
2.
3.
4.
5.
6.
Light enters the eye at the cornea, then passes
through a liquid until it reaches the pupil
Light enters the interior of the eye through the
pupil
The iris adjusts the pupil to control the amount
of light entering.
The light then passes through the lens which
bends the light rays.
Through a process known as accommodation,
muscles around the lens alter its shape to adjust
to viewing objects at different distances and to
allow the lens to focus light on the retina.
Finally, the retina will convert light energy into
neural energy. Nasa retina ung photoreceptors
 Note that image hits the retina upside
down. The brain reorients the
inverted image, so that our world is
right side up.

Simple cells:
o these cells respond to very specific information,
such as a bar of light oriented at a particular
angle.
o Some simple cells respond to only one angle or
orientation
o while others respond to other angles of
orientation or to edges, shapes, and sizes of
lines.
Complex cells:
o receive input from many different simple cells
and are receptive to particular stimuli in
different parts of the receptive field.
o are sensitive to the movement of an image and
respond if the image appears anywhere in the
visual field.
Hypercomplex cells:
o receive inputs from many complex cells, so they
fire in response to patterns of lines.
o partially involved in integrating pieces of visual
information into whole parts.
PERCEIVING VISUAL STIMULI
The eye is where we sense visual
information and the brain is where we make sense of
it (perceive visual information). But making sense or
perceiving of the neural information from the eye
involves many different acts of perception: color,
motion, depth, size, and patterns among others.
Perceiving Color
Primates – including humans – have three
kinds of cones: those that are sensitive to red, to
green, or to blue wavelengths of light (Jacobs &
Nathans, 2009). Humans therefore are trichromatic.
Theories of Color Vision
1. Trichromatic Color Theory
- reasoned that all the color we
experience must result from a mixing
of these three colors of light (red,
green, and blue).
- cannot explain some aspects of color
vision such as afterimages, visual
images that remain after removal of
stimulus.
2. Opponent-Processing Theory
- cones are linked together in three
opposing color pairs: blue/yellow,
red/green, and black/white
Color blindness: a weakness of deficiency in
the perception of certain colors, usually
resulting from an inherited pigment deficiency
in the photoreceptors.
Perceiving Motion
 Feature detectors play a role in how we perceive
movement and form.
 We perceive movement when an image moves
across the retina.
 two factors contribute to how we perceive
movement;
o The background against which an object
moves: when an object moves across a
complex background, it appears to move
faster than when it moves across a simple
background. The human visual system is
quite sensitive to changes in the position
of objects, a sensitivity that appears to
decline a bit with age
o The size of the object: smaller objects
appear to move faster than larger objects,
when all else is equal. We can also be
fooled into thinking something is moving
when it is not. We refer to this illusion as
apparent motion because our brains
interpret images that move across our
retinas as movement.
Perceiving Depth
Depth perception is our ability to see
things in three dimensions and to discriminate what
is near, from what is far.


Binocular Depth Cues:
- it relies on input from both eyes.
- eyes are separated by a few inches, so
the images from each eye provide
slightly different viewpoints.
Monocular Depth Cues:
- aids to depth perception that do not
require two eyes to be effective
- allow people who are blind in one eye
to perceive some depth
o Linear perspective: involves
parallel lines that converge, or
come together, the farther away
they are from the viewer. The
more the converge, the greater
distance we perceive.
o Texture gradient: causes the
texture of the surface to appear
more tightly packed together as
the surface moves to the
background. Changes in this
information help us judge depth.
o Atmospheric perspective: it
comes from looking across a vast
space into the distance in the
outdoors.
o Interposition:
the
partial
blocking of objects farther away
from the viewer by objects closer
to the viewer, which overlap
those farther away.
o Moon illusion: occurs when the
moon is closer to the horizon
because we see it against other
cues that indicate we are looking
off into the distance.
Perceiving Size and Shape
Perceptual constancy is the brain’s ability to
preserve perception of objects in spite of changes
in retinal image when an object changes in position
or distance from the viewer.
 Size constancy: we see things as the same size
regardless of the changing size of the image on
the retina, because we know what the size of
the object is. For example, your friend who
stands 6ft and walking away from you would
not make you think that he is shrinking.
 Shape constancy: people know the shapes of
common things, just as they know their sizes.
The brain uses this knowledge to change retinal
images that make the world very confusing.
The brain corrects our perception based on our
previous knowledge.
Perceiving Patterns and Wholes
 Similarity: Gestalt law that says we tend to
group like objects together in visual perception.
 Continuity: seeing points or lines in such a way
that they follow a continuous path.
 Proximity: claims that we tend to group
together objects that are near one another.
 Law of closure: it occurs when we perceive a
whole object in the absence of complete
information.