- Psychological science is both empirical and determinism. Behavior comes from observing what
we see and measure caused by many factors.
Empiricism: a philosophical theory that knowledge comes through experience.
Knowledge about the world is based on careful observation and not on speculation or
common sense. Whatever we see or measure should be observable by everyone else who
follows the same method. Scientific theories must be rational and must explain how they
fit together. Seeing is believing but reasoning about observations is just as important.
Determinism: the belief that all events are governed by lawful, cause and effect
relationships. This is easy to understand when we discuss natural law, if you drop a
textbook, it will fall. There is evidence that our behaviors are determined so that we
don’t really have free will, we can’t really do whatever we want. Behavior is determined
by internal (genes, brain chemistry) and external influences (world, media)
-Zeitgeist: general set of beliefs of a particular culture at the specific time in history.
=> used to understand why some ideas are noticed immediately, and some good
ideas go unnoticed for years.
- Average person in 1600’s would be troubled with viewing human behavior as result of
predictable physical laws. This would imply that the philosophy of materialism was true.
- Materialism: humans and other living being composed exclusively of physical matter.
Accepting this idea would mean that we’re nothing more than complex machines that
lack a self-conscious, self-controlling soul.
- Dualism: properties of humans that aren’t material (a mind or soul separate from the body).
- Most early thinking about the mind and behavior remained a philosophical in nature, but
scientific methods were generating great discoveries for the natural sciences of physiology,
physics and biology.
INFLUENCES FROM PHYSICS: EXPERIMENTING WITH THE MIND:
- The initial ventures into scientific psychology were conducted by physicists and physiologists.
- One of the earliest explorations was made by Gustav Fechner who worked on sensation and
perception. He was interested in the natural world moving objects and energy as a physicist. He
turned his questions to psychological questions about how the physical and mental worlds
- Psychophysics, which is the study of the relationship between the physical world and the mental
representation of that world.
- Psychophysical research, you’re holding a one pound weight in your left hand and five pounds of
weights in the right hand, you’re right hand is going to feel the heavier weight. He then added
half a pound in each hand, but still the 5.5 pounds felt heavier in the right hand.
INFLUNCES FROM EVOLUTIONARY THEORY:
- Charles Darwin was studying the variety of plants and animals around the world.
Noticed animal groups that were isolated only had minor variations in physical features.
Variations seemed to help species adapt to particular habitat/environment and make
them better prepared for survival and reproduction. 2
Darwin said behavior and physical traits are shaped by natural selection.
Noticed survival and reproduction are closely related to a person’s ability to sense some
expressions as threats and others are submissions.
- Darwin’s recognition that behaviors, like physical traits are subject to hereditary influences and
natural selections was a major contribution to psychology.
INFLUNCES FROM MEDICINE:
- Medicine contributed a great deal to the biological perspective in psychology as well as clinical
- Clinical psychology: field of psychology that concentrates on the diagnosis and treatment of
- Brain localization: the idea that certain parts of the brain control specific mental abilities and
- In the 1800’s, two views competed against localization. The first was phrenology (which gained
popularity for 100 years thanks to Franz Gall and Johann Spruzheim) they believed that the brain
was consisted of 27 organs, corresponding to mental traits and dispositions that could be detected
by examining the surface of the skull.
- The other approach to localization entailed the study of brain injuries and the ways in which they
affected behaviors. They filled the gaps in science that phrenology lacked.
- Prolonged exposure to magnetics could redirect the follow of metallic fluids in the body, thereby
curing insanity and diseases. This is called psychosomatic medicine.
- Frank Mesmer called his exposure to magnets, hypnosis.
- Sigmund Freud began to use hypnosis on his own patients. He was interested on how it cured
patients with hysterical paralysis, which a person loses feelings and control in a specific body
part, despite the lack of any known neurological damage or disease. These experiences led to
Freud to develop his famous technique and theory called psychoanalysis.
- Psychoanalysis is a psychosocial approach that attempts to explain how behavior and personality
are influenced by unconscious processes.
- Freud acknowledged that conscious experiences include perceptions, thoughts, a sense of self and
the sense that we’re in control of ourselves. He also believed that the unconscious mind contained
forgotten episodes from early childhood and urges to fulfill self-serving sexual and aggressive
- Freud proposed this because these urges were unconscious, they could exert influence in strange
ways such as restricting the use of a body part.
- He thought that when a person was hypnotized, the psychoanalyst could have more direct access
into the individual’s unconscious mind. Once Freud gained access, he could attempt to determine
and correct any desires of emotions he believed were causing the unconscious to create the
- He didn’t do scientific experiments, but his work can be seen as key elements of scientific
- Medical model is the use of medical ideas to treat disorders of emotions, thoughts and behavior.
- He influenced scientific psychology by make inferences about unconscious mental activity, he
used the medical model and he used evolutionary thinking into his work; he emphasized how 3
physiological needs and urges related to the survival and reproduction can influence our behavior.
He also said that early childhood life influences our behaviors as adults.
THE INFLUENCES OF SOCIAL SCIENCES:
- Economics, sociology and anthropology were considered social sciences.
- These disciplines developed statistical methods for measuring human traits, which soon became
relevant to the emerging field of psychology.
- Sir Francis Galton measured perception and behavior. He was inspired by his cousin, Darwin
who had just published his theory of evolution by natural selection. Galton believed that genetic
explained psychological differences among people. The idea of hereditary psychology fit
Galton’s beliefs about social class. For example, he noticed that great achievements tend to run in
- Eminence means a combination of ability, morality and achievement. A closer the relative the
closer the traits was one of his supporting points.
- Galton was one of the first investigators to scientifically take on the question of nature and
nurture relationships, the inquiry into how nature and environments influence behavior and
mental processes. Galton supported the nature side which ignored the likelihood that nurturing
influences such as upbringing and family traditions, rather than biological endowments, could
explain similarities among relatives.
- He also supported his beliefs by ignoring the fact that great people can and do come from very
- Galton’s beliefs and biases led him to pursue scientific justifications for eugenics, which meant
good genes. He promoted the belief that social programs should encourage intelligent, talent
people to have children whereas criminals, those with physical and mental problems and
nonwhite races should be keeping out of the English gene pool.
- Eugenics was based on what researchers believed to be true and not research methods.
- Eugenics led to the mistreatment of many people.
- Galton used statistical methods to measure and study behavior and mental processes.
STRUCTURALISM AND FUNCTIONALISM:
- Wilhelm Wundt established the first laboratory dedicated to studying human behavior and was
responsible for establishing psychology as an independent scientific field. He did many
experiments on how people sense and perceive. His primary research method was introspection,
meaning to look within.
- Introspection required a trained volunteer to experience a stimulus and then report each person
sensation he or she could indemnity through introspection. If the person was given a steel ball to
hold in one hand, they would report sensations of smooth, hard, heavy and cold.
- To Wundt, these basic sensations were the mental atoms that combined to form the molecules of
experience. He also developed reaction time methods as a way of measuring mental effort.
- Structuralism was an attempt to analyze conscious experience by breaking it down into basic
elements, and to understand how these elements work together.
- Titchener chose the terms elements on purpose as an analogy with the periodic table. He believed
that mental experiences ere made up of a limited number of sensations, which were analogous to
elements in physics and chemistry. 4
- William James wrote the first textbook in psychology, The Principles of Psychology which was
published in 1890. He wanted to know how the mind functioned.
- Functionalism is the study of the purpose and function of behavior and conscious experience.
- Evolutionary psychology, an approach that interprets and explains modern human behavior in
terms of forces acting upon our distant ancestors. Our brains and behaviors have been shaped by
the social and physical environment that our ancestors encountered.
THE RISE OF BEHAVIORISM:
- In the twentieth century, biologists became interested in how organisms learn to anticipate their
bodily functions. One of the first to do so was Professor Edwin Twitmyer. He was interested in
- His work involved a contraption with a rubber mallet that would regularly tap the patellar tendon
just below the kneecap. Which caused a kicking reflex in most people?
- Behaviorism: an approach that dominated the first half of the twentieth century of American
psychology and had a singular focus on studying only observable behavior with little to no
reference on mental events or instincts as possible influences on behavior.
- He wanted to condition humans like Pavlov conditions dogs to salivate when they heard a bell.
- All behaviors could be explained though conditioning.
- Skinner believed that psychology was the study of behavior and not of the unobservable mind.
- Skinner wanted to see how rewards affect behaviors. His method was organisms repeat behaviors
that give them a reward but avoid those that don’t give a reward. He did this study mostly with
- Rewards motivate us and influence our behavior.
- Other psychologists disagreed with this because they said if we are driven by rewards then we
don’t really have free will.
HUMANISTIC PSYCHOLOGY EMERGES:
- Humanistic psychology focuses on the unique aspects of each persons, each person’s freedom to
act, his or his rational thought and the belief that humans are fundamentally different from other
- Humanistic psychologists wanted to understand the meaning of personal experience. They
thought that people could have mental well-being and satisfaction through gaining a greater
understanding of themselves, rather than by being diagnosed with a disorder or having their
- Rogers and Maslow believed that humans strive to develop a sense of self and are motivated to
personally grow and fulfill their potential.
- The humanistic perspective also contrasted with behaviorism in proposing that humans had the
freedom to act and a rational mind to guide the process.
THE COGNITIVE REVOULTION:
- Hermann Ebbinghaus produced data on remembering and forgetting. He figured out that a person
will quickly forget what they have learned.
- Bartlett’s work said we can remember general storylines but not the script or quotes. We
remember what we think is important enough for us to remember. 5
- Gestalt psychology, an approach emphasizing that psychologists need to focus on the whole of
perception and experience, rather than its parts.
- Cognitive psychology deals with memory, thinking and language.
SOCIAL AND CULTURAL INFLUENCES:
- Being in the presence of others affects our behavior. This is shown when a cyclist rode faster
when in the presence of other people.
- They tried to understand how Hitler changed good people into bad people.
- How Hitler’s anti-Jewish agenda affected others.
- Social and personality psychology is the study of the influence of other on our behavior along
with what makes each person unique.
- Lewin said that all behaviors could be predicted and explained through understanding how a
person with a certain set of traits would respond in a context that involved a certain set of
conditions. A quiet person and a loud person would react differently in the same setting.
- Cross-cultural psychology is the field that draws comparisons about people and group behavior
among cultures; it helps us understand the role of society in shaping beliefs, values and behaviors.
MODULE 1.3: PUTTING PSYCHOLOGY TO WORK:
- Jesse Purdy, a psychology professor studied social behaviours of seals in Antarctica, conducts
research on a cuttlefish, which is close to an octopus. Psychologists work in a wide range of
areas, not just the stereotypical lab room.
- Psychologists deal with a wide range of behaviours.
- Any field that uses thinking or behaving, you will label as psychology.
- Applications of psychology, which means they involve a scientific approach to behavior and
- Those who earn a Doctoral degree (PhD) in psychology work in a variety of settings, with the
most common being at Universities and colleges teaching.
- Research psychologists typically work at universities, in corporations, in the military, and in
governmental agencies (such as the National Institutes of Health and Mental Health)
- Many psychologists work in these different settings focusing on applying basic principles of
psychology to the real world.
- Applied psychology uses psychological knowledge to address problems and issues across various
settings and professions including: law, education, clinical psychology, business organization and
management. Basic or applied work, depending on where you’re employed.
- Psychology instructor is employed in academic psychology, part of the time.
- Academic psychologists work in colleges and universities and combine research and teaching
although some do one or the other. Academic psychologists don’t like to refer to themselves as
being academic psychologists, most academic psychologists would describe themselves by their
specialization “I’m a clinical psychologist” or “I’m a social psychologist.”
PSYCHOLOGICAL HEALTH AND WELL-BEING:
- For most people, mental health first comes to mind when they think about psychology.
- People think psychologists analyze people (stereotype)
- Mental health sector is largest employment field for people with advanced psychology degrees.
- Helping professions aren’t limited to people with psychology degrees. 6
- Mental health jobs are called helping jobs because they have in common, rather than specific
educational criteria, degrees or occupational roles.
- Why are there so many different job descriptions? One is to distinguish education levels and the
other is to consider the most effective treatment by the different professions. For example,
psychiatry is a branch of medicine concerned with the treatment of mental and behavioral
- As physicians, psychiatrists are likely to prescribe drugs such as antidepressants.
- Clinical and counseling psychologies are more likely to emphasize psychological approaches to
treat mental health concerns and disorders.
- Social workers emphasize the social context of a person’s treatment such as the family dynamics
or social or economic status.
- Psychologists may work with a master’s degree but many go onto pursuing doctoral degrees.
- Doctor of Philosophy (PhD) combines study with practice.
- Doctor of Psychology (PsyD) is specialized and almost exclusively focuses on the practice of
- Psychologists can also specialize to practice in specific contexts.
- Forensic psychology encompasses work in the criminal justice system, including interaction with
the legal system and its professionals. Often glorified in movies and on TV as criminal profiling
and investigation, but it’s a very practical profession this involves very little of what is seen in the
- Few criminal profilers work with the FBI and larger law enforcement agencies to develop a set of
characteristics that are statistically related to a criminal’s method.
- More likely to see forensic psychologists work in prisons, training and evaluating police officers
or assisting with jury selections and evaluating whether defendants are able to stand trial.
- School psychology means working with students who have special needs, such as those with
emotional, social or academic problems. School psychologists may find ways to change troubling
or disruptive behavior or a cognitive disability such as dyslexia which interferes with learning.
They spend a lot of time observing a child’s behavior or administering special psychological test
to identify learning disabilities. Rarely work alone, most are part of an educational team which
include their parents, teachers and counselors.
- Most helping professions have graduate degrees and licensure or certification as approved by
- Many people rather start a career than go for another degree.
- With a bachelor’s degree, people can work in treatment settings on a basic level.
- Health psychology means (or behavioral medicine) they study of how individual, biological an
environmental factors affect physical health. Health psychologists identify behaviours and
personality traits that put people at risk, and that, when combined with an unfortunate genetic
heritage, infection, lead to disease. For example, poor food choices and overeating have been
linked to diabetes. Long hours at work scarify relationships, can affect your health.
- Might be seen as the behavioral counterparts to practitioners of traditional medicine. Physicians
treat the physiological effects of a disease psychologist help to change the related behaviours.
- One of the fastest growing fields within psychology is Industrial and Organizational (I/O)
psychology: a branch of applied psychology in which psychologists work for businesses and
other organizations to improve employee productivity and the organizational structure of the 7
company or business. May develop tests to hire workers who have the best chance at succeeding,
may assist work teams to improve communication and responsibility and they may help
organizations with the management of change.
- Closely related to I/O psychology is human factors psychology, the study of how people interact
with tools, physical spaces or products. Highest branch of applied psychology. Great deal of work
is done with principles of sensation and perception to complex work environments such as
aircraft cockpits or laparoscopic surgical devices. May study human-computer interactions to
develop user-friendly software and products.
- Environmental psychology studies factors that improve working and living conditions, but they
do so by establishing how the environment affects individuals or groups. Results from this type of
research may be used in the design of working and living spaces to foster communication, to
reduce distractions and to prevent or reduce strain, stress and fatigue.
- Many psych undergrads work in marketing, marketing deals with a lot of research on what he
consumer wants, what buyers expect and what makes shoppers chose one product over another.
- Marketing professionals conduct surveys and experiments on preferences, such as the taste tests
we see on TV.
- Only a small percentage of the 100,000 psych undergrads will go onto working in a field of
psychology. The world only needs so many psychologists. Students who major/minor in psych
can use their knowledge in many other fields because psych emphasizes research, psych majors
are excellent problem solvers and critical thinkers. Psych majors learn many principles of human
behavior, ranging from individual cognition to group dynamics, which are needed skills for
managers, teachers and marketers. Understanding how behavior works to your advantage
regardless of what career you chose.
- Mozart effect listening to classical music apparently makes you smarter.
- Single most important aspect of scientific research: objectivity assumes that certain facts about
the world can be observed and tested independently from the individual. No bias, just facts.
Everyone, not just experts, should agree on these facts given the same tools, methods and
contexts. Objectivity isn’t simple. Whenever people observe something, there interpretation of it
becomes subjective, meaning that their knowledge of the event is shaped by prior beliefs,
expectations, experiences and even their mood. Objective approaches differ from subjective ones.
Most see scientific approach as rigorous and demands proof, these aren’t inaccurate
characterizations but there is more to explore.
- Five characteristics of Quality Scientific Research: developed by scientists over the past few
centuries to help us bring an objective understanding of the world. Drive for objectivity
influences how scientific research I conducted. Quality scientific research’s meets the follow
criteria (good for any research that you do):
a. It’s moved on measurement hat are objective, valid and reliable.
b. It can be generalized.
c. It uses techniques that reduce bias.
d. It’s made public.
e. It can be replicated. 8
- Foundation of scientific methodology is the use of objective measurements, the measure of an
entity or behavior that, within an allowed margin of error, is consistent across instruments and
obverses. No bias. A poster of Yuri should weight the same on any scale that you use.
- Objective measures may include physical recording devices, but most often the researcher does
the recording. Objectivity can come from the person measuring it.
- Variable means refers to the object, concept or event being measured (amount of sugar I put in
my coffee and a speedometer in your car)
- Psychologists found some instruments to measure variables related to behaviours and thought,
still can’t read your mind though but tons of measures are available for psychological
observations (take form of behavioral measures)
- Most of 20 century, American mainstream psychologists focused on behavioral measures,
remained core of psych research.
- New technology, especially from the field of neuroscience, has expanded the variables for
psychologists to study.
- High tech equipment such as MRI machines allows researchers to see your brain. Other psych
measures include gathering your blood or salvia which can then be analyzed for enzymes,
hormones, and other biological variables that relate to behaviours and mental functioning.
- Self-reporting, a method in which responses are provided directly by the people who are being
studied, typically through, face-to-face interviews, phone surveys, paper and pencil test and web-
based questionnaires. These are often obtained in forms of surveys that include scale’s measuring
attitudes, opinions, beliefs and abilities. May inquire about shyness, mood or political orientation
by asking humans to rate their agreement with a set of statements (1-5). College kids,
achievement and intelligent tests that are designed to measure cognitive abilities or performance.
- Any method used by a research needs clearly defined terms, shyness, mood etc…
- Operational definitions are statements that describe the producers or operations and specific
measures that are used to record observations.
- Operational definition ~ Mozart effect. How do the researchers define the outcome of their study?
- Behavioral measures need to be reliable and valid.
- Measure demonstrates reliability, when it provides consistent and stable answers across multiple
observations and point in time. Judges at the same time but independently rate dancing. High
reliability is when judges rock the same scores, like if a dude gives a high score then the other
dude should too.
- Watch same people to see signs of aggressive behavior.
- Judges must be trained to use operational definitions to have high reliability.
- People do the measurements, but reliability works for measurement tools too such as a stopwatch,
scale, brain imaging scanners and questionnaires. These need to be consistent in their recordings.
- Reliability is close to validity, the degree to which an instrument or produce actually measures
what it claims to measure. What is someone measured intelligence based on shoe sizes? Could
give clear operational definition and his measure would be reliable. A tape measure should give
the answer each time a foot is measured, but it’s not valid measure to measure intelligence.
Rather than shoe size, measure a dude’s intelligence with a test, stuff that is in line with the
definition of intelligence. 9
- Reliability and validity are essential components of scientific research; knowledge gained from
scientific studies should be useful beyond a lab.
- Testimonies are cute, good success stories can be powerful. Diet pills may work for a dude but
may not work for a girl. We don’t even know if it worked for the person, could’ve been a
- When we apply info from one person to another, we are generalizing. Generalizability refers to
the degree to which one set of results can be applied to other situations, people or events.
- Results will generalize if you study a large group of people, you can get a better sense how
people are likely to behave. Ideally, it would be good to study entire population, the group that
researchers want to generalize about. Getting the population and persuading everyone to do the
survey is impossible in most cases. They just use a sample instead, a select group of population
members. Once the sample is done, the results can be generalized to the population as a whole.
- Random sampling whenever possible is good; every person of a population has an equal chance
of being selected. Study kids at school; get the computer to generate a random list. Can be hard to
do a true random sample.
- Convenience sample, people who are readily available.
- Random sampling can help research generalize. Research is generalized around time and space.
- Lab research includes any study conducted in an environment controlled by the researcher,
whereas naturalistic research takes place where the behavior would typically occur. Many
researchers rather lab cause specific conditions manipulate behavior. Artificial nature of lab can
interfere with normal behavior, which would affect the generalizability of the findings.
- Ecological validity is the degree to which the results of a lab study can be applied to or repeated
in the natural environment. Bring people to a lab to test them might get better results than test
kids in a classroom for real marks.
- Animals, people or the research can introduce bias in the study.
- Hawthorne Effect is a term used to describe situations in which behavior changes as a result of
- Biases: researcher bias (person doing the experiment) and subject bias (person being tested)
- Demand characteristics, inadvertent cues given off by the experimenter or the experimental
context that provides information about ho participants are expected to behave. Very subtle to
- Socially desirable responding which means that participants respond in a way that increases the
changes that they will be viewed favorably.
- Placebo effect is a measureable and experienced improvement in health or behaviours that cannot
be attributed to a medication or treatment.
- Anonymity – no name or person info written down.
- Confidentiality – results only seen by researcher.
- Single blind study – participants don’t know true nature of the study or don’t know the treatments
they are getting (drugs, placebo), blind to the purpose of the study.
- Double blind study – neither the participant nor the experimenter knows the exact treatment for
any person. Reducing bias.
- Psych primary mode of communication is academic journals.
- Profs do essays and get it peer reviewed. 10
- Anecdotal evidence – a person’s story or testimony about an observation or event that is used as
evidence. Weight loss pill. Poor evidence.
- Appeal to authority – when an expert makes a claim to be true with no supporting facts or
- Appeal to common sense – a claim that appears to be sound, but lacks supporting scientific
- Appeals to tradition – we’ve always done it this way.
- Appeals to novelty – latest thing out.
...Guide investigators in
1. Organizing the study
2. Making observations
3. Evaluating the results
An opportunity to present observations about the characteristics of the subject
Eg. How many hours per week does the typical university student spend on homework?
- Research questions address
a) Appearance of behavior
c) Prevalence in a population
- Measuring the degree of association between two or more variables
- Psychologists doing descriptive research almost always record about multiple variables
- Will ask whether the variables tend to occur together in some pattern or at opposite times
- Eg. What are the high school graduation rates in each county of your state?
- Designs improve on descriptive correlational studies because they are the only designs that can
provide strong evidence for cause and effect relationships
The Experimental Method
- Random Assignment A technique for dividing samples into two or more groups (assign
random people to groups assuming they will be relatively equal (instead of dividing into
something like tall, short, boy, girl, brunette, blonde etc) )
- Confounding Variables Variables outside of researchers control that might effect the results
- The Experimental Group Group exposed to dependent variable
- Control Group Doesn’t receive the treatment, used as comparison
The Quasi-Experimental Method
- Research technique in which two or more groups that are compared are selected based on
predetermined characteristics rather then randomly assigned (Eg. Comparison between men and
- Quasi experiments are actually correlation studies – they can point out relationships among
preexisting groups and certain variables, but they can not determine what it is about those groups
that lead to the differences
Genetic and evolutionary perspectives on behaviour
Women were rated as better dressed when they were in their peak level of fertility of the menstrual
Are we the product of our genes [nature] or the environment in which we are raised [nurture]?
Humans tend to think in black or white
Heredity and behavior
Nucleus: genetic code
Genes: basic unit of heredity; resp for guiding the process of creating proteins that make up the
physical. They regulate development, physiological processes
o Chromosomes: structures in cellular nucleus lined with all of the genes an individual inherits
DNA (deoxyribonucleic acid): molecule formed in a double-helix shape that contains four amino
acids: adenine, cytosine, guanine, thymine. [abbreviated] [code to create proteins]
Genes instruct cell
Genotype: the genetic makeup of an organism [inheritance[
Phenotype: observable characteristics, physical structures, behavior.
Homozygous: the same. Two corresponding genes at a given location on a pair of chromosomes
Taster vs non taster
Heterozygous: different traits
o Dominant gene: homozygous dominant TT
o Heterozygous Tt
Behaviourial genetics: study of how genes and environment influence behaviour
o Involves comparing people of different levels of relatedness
Comparison between identical and fraternal twins
o Monozygotic: comes from a single ovum, genetically identical
o Dizygotic twins (fraternal): t separate eggs fertilized by two different sperm cells that
share same womb.
Behavioral geneticists use twin studies to calculate heritability
o Heritability statistic, expressed as number between zero and one, represents degree to
which genetic differences between individuals contribute to individual differences in a
behavior or trait found in a population.
0 heritability: genes do not contribute to individual differences in at trait
o 1.0 heritability: genes account for all individual differences in a trait
Adopted children were studied to estimate genetic contributions to behavior
o Family represents nurture side
o Biological family represents nature
Behavioral Genomics: Molecular Approach
Behavioral genomics: study of DNA and the ways in which specific genes are related to behavior.
Human GENOME project
Identification of 30,000 genes
o An abundancde of new techniques and information about where genes are located, and it
opened the door for an entirely new era of behavioral genetics.
o Researchers can examine genes that are present among individuals diagnosed with a disorder
that are not prsent in other people 12
Modern human behavior as an outcome of the processes of survival and reproduction among our
early human ancestors.
Adaptations (trait): contribute to health, survival, health, sexual behavior.
o Most likely to pass these genes to the next generation compared to individuals with traits that
do not contribute, or even hurt, chances for survival and reproduction
o Evolution: change in the frequency of genes occurring in an interbreeding population over
CHARLES DARWIN: natural selection: process by which favorable traits become increasingly
common in a population of interbreeding individuals, while traits that are unfavorable become less
Female preferences are consistent with the biological fact that there are limits to how many children
they can bear in a lifetime. Males consistent with healthy offspring.
Attraction and symmetry
o External features of human body and face are geneticaly programmed to be symmetrical.
Each side is a mirror image of the other. Rarely prefect. Asymmetry like illness.
o Psychologists test how sensitive we are to deviations from symmetry and how our detection
of asymmetry affects our preferences for others.
o We prefer symmetrical faces
o Physical can determine whether we might want to approach someone, and sepnd time.
Symmetry plays a role in how we initially respond to others, but it is not of importance long
o Symmetry is hypothesized to be a physical display of mate quality because it signals that the
individual is genetically healthy.
Cultural and environmental contributions to behaviour
Stereotype threat: Researchers can produce lower math test stores among women just by having
them read a passage claiming a genetic basis for gender differences prior to taking a math test
o Redirects brain activity from math problem-solving to areas concerned with social interaction
o Conclusion: gender differences occur usually because people believe gender differences exist.
Serotonin: brain chemical associated with mood. Imbalances of serotonin is a sign of depression
o (DNA) People who inherit two copies of short version are at greater risk for developing
Those who inherit two long copies are at far less risk for depression
o Heterozygous of both DNA's show intermediate responses to stressful events
o The stress is critical in this experiment.
o The gene--environment interaction becomes apparent after an accumulation of events.
Male and female brains will differ in some ways b/c males and females have had to solve different
set of problems in order to survive and reproduce.
o An example of this is the 'mental rotation task'. The males usually do better, and this may be
because their brains have been specialized for mental rotation tasks and that their testosterone
levels were high.
How the Nervous System Works: Cells and Neurotransmitters
Nervous system acts as a communications network. Transmits and receives info. It signals pain,
pleasure, emotion. Controls our reflexive responses. 13
Neurons: the major types of cells found in the nervous system, which are responsible for sending
and receiving messages throughout the body. They have different sizes.
o Cell body/soma: the part of a neuron containing the nucleus (genetic material). genes in the
cell body synthesize proteins that form chemicals and structures that allow neurons to
o Dendrites: small branches radiating from the cell body. Receives messages from other cells
and transmit the message toward the cell body.
o Axon: structure that transports info from the neuron to neighboring neurons in the form of
electrochemical reactions. At the end of axon, are axon terminals. Within the axon terminals,
are chemicals called neurotransmitters.
o Neurotransmitters: chemicals that function as messengers allowing neurons to communicate
with each other. They released across synapses.
o Synapses: microscopically small spaces that separate individual nerve cells.
o NOT all neurons are the same; they differ in function/form.
o Sensory neurons: fetch info from the bodily senses and bring it toward the brain. Neurons
responding to touch or pain sensations of skin bring the msg to spinal corn -> brain.
o Motor neurons: carry messages away from the brain and spinal cord and toward muscles in
order to control their flexion and extension.
Glial Cells 14
Myelin: fatty sheath that insulates axons from one another, resulting in increased speed and
efficiency of neutral communication.
Multiple sclerosis: disease in which the immune system does not recognize myelin and attacks it
This devastates the structural and functional integrity of the nervous system
o Symptoms: numbness, tingling sensations caused by disruption of sensory nerve cell signals
that should otherwise reach the brain.
o Multiple sclerosis is characterized by problems with voluntary, coordinated movement which
causes the breakdown of myelin supporting motor nerves.
Myelin is made up from a highly abundant type of cell called glia. Glial cells: specialized cells of
the nervous system that are involved in mounting immune responses in the brain, removing wastes,
synchronizing activity of the billions of neurons.
o Outnumber the brain by 10:1
o The structure/function of these cells are different.
o The activity of neurons highly depends on glial cell interaction
The Neuron's Electrical System: Resting and Action Potentials
Resting potential of a neuron: refers to its relatively stable state during which the cell is not
transmitting messages (RP: Resting Potential)
o At RP Neuron exterior: high concentration of +charged ions (sodium/potassium)
o At RP Neuron interior: relatively high concentration of -charged chloride ions.
o Difference in charge -70mV
Stimulated neuron -> neural firing
o Neuron firing opens the membrane pores and allows positively charged sodium ions to rush
in. a sufficient number of Na ions alter the charge to be greater than -70mV.
o Ea neuron has a specific threshold that must be reached before it will fire.
Action potential: a wave of electrical activity that originates a the base of the axon and rapidly
travels down its length
o Action potential moves down axon and positively charged ions rush thru membrane pores.
Cell goes from neg -> pos charge. Sodium pores slam shut as soon as action potential occurs.
Sodium ions are rapidly pumped back out of the cell; returns to resting state.
When action potential reaches axon terminals at the end of the cell, neurotrans are released
intosynaptic cleft:minute space between the terminal button and the dendrite, and bind to
receptors on the dendrites of neighboring neurons.
o Followed by AP is Refractory period: brief period in which neuron cannot fire.
All-or-none principle: individual nerve cells fire at the same strength every time action potential
Neurogenesis: formation of new neurons--in a limited number of brain regions 15
The Chemical Messengers: Neurotransmitters and Hormones:
Lock-and-key analogy explains how neurotransmitters and their
When neurotransmitters are released at axon terminal, they cross
the synapse and fit in a particular receptor of the dendrite like a key in a
A successful bind to the receptor triggers 1 or 2 types of
reactions in the receiving neuron
Effect can be excitatory (increase action potential) or inhibitory
(decrease action potential)
After neurotransmitter molecules have bound to postsynaptic
receptors of a neighboring cell, they are released to synaptic cleft
Might break down into enzymes
Others will go through reuptake, a process whereby
neurotransmitter molecules that have been released into the synapse are
reabsorbed into axon terminals of presynaptic neuron.
Ex of reuptake) the class of antidepressant drugs (selective
serotonin reuptake inhibitors) (SSRI) [prozac] inhibits reuptake of the
Types of Neurotransmitters
Monoamines: one class of neurotransmitter
o Influence mood
Doapmine: monamine neurotransmitter involved in such varied functions: mood, control, voluntary
movement, processing of rewarding experiences
Serotonin: monoamine regulating mood, sleep, appetite.
Norepinephrine: monoamine regulating stress responses, including arousal, attention, heart rate.
o Synthesized from dopamine molecules
Acetylcholine: voluntary movement, arousal, attention
o Widespread neurotransmitter
o Found at the junctions between nerve cell/skeletal muscles
o Combined activity w/ dopamine
GABA (gamma-amino butyric acid): prevents neurons from generating action potentials. Facilitates
sleep and reduces arousal.
o Primary inhibitory neurotransmitter
o Reduces negative charge of neighboring neurons even further than their restate state of -
Causes influx of neg charged chloride ions to enter cell when bind to receptor
Glutamate: excitatory neurotransmitter critical for learning/memory.
Pain and Substance P
Substance p: neurotransmitter involved in experience of pain.
o Sensory nerves in brain and spinal cord.
o When skin tissue is damaged, the brain releases substance P (pain)
o Ex) Capsaicin: pain inducing compound found on chili peppers
Naked mole rat does not show pain to capsaicin, pain pathway modified thru evolution due to the
CO2 environment. 16
o Congenital insensitivity to pain: lack ability to perceive path and even in early childhood
acquire significant damage to skin, joints, eyes and other regions on body.
o Do not prevent damage to body
Drug Effects on Neurotransmission
Agonists: drugs that enhance/mimic effects of a neurotransmitter's action.
o Ex) nicotine: acetylcholine agonist; stimulates receptor sites for this neurotransmitter
Ex) xanax: gaba agonist; increases activity of this inhibitory neurotransmitter.
Direct agonist: physically binds to receptors at the post synaptic cells.
Indirect agonist: facilitates neurotransmission by increasing the release and avail. Of
Antagonists: inhibit neurotransmitter activity by blocking receptors or preventing synthesis of a
o Ex) botox: paralyze muscles to inc. youthful appearances
Hormones and the Endocrine System
Hormones: chemicals secreted by the glands of the endocrine system
Homeostasis: balance of energy, metabolism and temperature.
Hypothalamus: brain structure that regulates basic biological needs and motivational systems
o Stimulates pituitary gland: master gland of endocrine system that produces hormones and
sends commands about hormone production to other glands of the endocirne system.
o Sets chemical events in motion that physically prepare us for stress. It signals pituitary to
release adrenal glands: pair of endocrine glands located adjacent to the kidneys that release
stress hormones ex) cortisol/epinephrine.
Endorphin: hormone produced by pituitary gland and the hypothalamus that functions to reduce
pain and induce feelings of pleasure.
o Released during exercise, sexual activity, injury
o Inhibits perception of pain, increases euphoria
Morphine-- drug derived from poppy plan, binds to endorphin receptor and produces same
Testosterone: drives physical and sexual development over long term, surging during sexual
activity and in response to threats
o Male sexual development and function
o Testosterone apparently causes aggression
o Correlated with more aggressive thoughts and feelings. Not to be confused with physical
o Testosterone lvls increase after men win sports/chess matches
Hormones facilitate behaviour; they do not cause behaviour.
Structure and Organization of the Nervous System 17
Peripheral nerv system (PNS): transmits signals between the brain and the rest of the body and it is
divided into two subcomponents:
o Somatic nervous system: consists of nerves that receive sensory input from the body and
control skeletal muscles responsible for voluntary and reflexive movement
o Autonomic nervous system: portion of the peripheral nervous system responsible for
regulating the activity of organs and glands. It includes two subcomponents:
Sympathetic nervous system: responsible for the fight-or-flight response of an
increased heart rate, dilated pupils, decreased salivary flow--responses preparing body
Parasympathetic nervous system: maintains homeostatic balance in the presence of
change; following sympathetic arousal, it works to return the body to a baseline,
Central nervous system (CNS): brain and spinal cord
o Brain personality, preferences, memories, conscious awareness
o Spinal cord connects brain with peripheral nervous system, forming a network spanning
The Brain and Its Structures
Hindbrain: structures critical to controlling basic, life-sustaining processes
(top of spinal cord) Brain stem:dulla and the pons
o Nerve cells in medulla regulate breathing, heart rate, sneezing, salivating, vomiting
o Pons contribute to general levels of wakefulness. 18
Reticular formation: sends signals upward into cortex, higher brain center we will
describe shortly to influence attention and alertness.
Cerebellum (little brain):lobe-like structure at the base of the brain involved in the details of
movement, maintaining balance, and learning new motor skills
Midbrain: resides just above the hindbrain and primarily functions as relay station between
sensory and motor areas.
o Tectum: coordinates sensation of motions with actions. Ex) pigeon
Includes neurons that contain very dense concentrations of dopamine receptors and activity.
Ex) parkinsons disease caused by loss of dopamine-producing cells
The Forebrain: Memory and Thought
Forebrain: most visibly obvious region of the brain, consists of multiple interconnected structures
critical to complex processes as emotion, memory, thinking and reasoning.
Basal ganglia: involved in facilitating planned movements, skill learning, and integrated with
brain's reward system.
o Tourettes) condition marked by erratic and repetitive facial and muscle movements, heavy
eye blinking, frequent noise making. Excess dopamine transmitted within the basal ganglia
contributes to tourette sympoms
o Nucleus accumbens: pleasurable experiences, rewards and thrills. Commonly abused drugs
target dopamine transmission in nucleus accumbens
Limbic system: integrated network involved in emotion and memory
Amygdala (almond): facilitates memory formation for emotional events, mediates fear
responses, and appears to play a role in recognizing and interpreting emotional stimuli,
including facial expressions.
o Hippocampus (seahorse): critical for learning and memory, particularly the formation of
o Thalamus: involved in relaying sensory information to different regions of the brain.
Cerebral cortex: convoluted, wrinkled outer layer of the brain that is involved in multiple higher
functions such as thought, language and personality.
Wrinkly surface of brain is because the skull can only be so large. The brain has
countered this constraint by forming a wrinkly surface.
o Ventricles:contain cerebrospinal fluid, solution helping to eliminate wastes and provide
nutrition to hormones to the brain and spinal cord. The fluid is also cushiony
Corpus callosum: collection of neural fibres connecting the two hemispheres
o Lobes: frontal, parietal, occipital, temporal lobes.
o Frontal: important in numerous higher cognitive functions; planning, regulating impulses,
emotion, language production, voluntary movemen
Primary motor cortex: involved in control of voluntary movement.
Dr. hatsopoulous monkey and quadriplegic human experiment
o Parietal: located behind frontal lobes. Involved in our experiences of touch as well as bodily
Somatsosensory cortex: band of densely packed nerve cells register touch sensations.
o Occipital lobes: located at the rear of the brain, where visual info is processed.
o Temporal: located at the sides of the brain near the ears and are involved in hearing,
language, and some higher-level aspects of visions such as object and face recognition
Sensation and Perception at a Glance 19
Sensation: process of detecting external events by sense organs and turning these events into
Sensory lvl: sound of someones voice is noise, sight of a person is a combo of color and
o Sensory receptors: structures that respond to external stimuli are stimulated. These are inside
the eye, over the tongue and nasal cavity.
Perception: involves attending to, organizing and interpreting stimuli that we sense.
Recognizing sounds as a human voice, understanding colors, shape and motion.
Transduction: process in which physical or chemical stimulation is converted into a nerve impulse
that is relayed to the brain.
o Cochlea: location of transduction of sound
Sensory adaptation: reduction of activity in sensory receptors with repeated exposure to as
o Ex) walking out of a dark theatre and into the bright, main lobby.
Psychophysics: the field of study that explores how physical energy such as light and sound and
their intensity relate to psychological experience.
Popular approach: measuring the minimum amount of a stimulus needed for detection, and
the degree to which a stimulus must change in strength for the change to be perceptible.
Absolute threshold: the minimum amount of energy or quantity of a stimulus required for it to be
reliably detected at least 50% of the time it is presented.
Difference threshold: smallest detectable difference between stimuli.
o Just noticeable difference: depends on intensity of original stimulus.
Signal detection theory: states that whether a stimulus is perceived depends on both sensory
experience and judgement made by the subject. Two processes: sensory and decision
o Sensory process: fain stimulus
o Decision process: subject asked to report whether it was present
Ability to detect weak stimulus depends on expectations, arousal level, and motivation
o Motivational changes are likely to affect decision process 20
Sensory judgement process has four outcomes
o Hit: correctly heard a sound
o Correct rejection: did not hear a sound
False alarm: heard something that isn't there.
o Miss: failing to detect a presence
Weak stimulus could have psychological effect even though it would reside below the level of
Subliminal stimuli: perception below conscious thresholds
Contours: subjective contours because they are not physically "there"
Gestalt Principles of Perception 21
Gestalt psychology: approach to perception that emphasizes "the whole is greater than the sum of
o Individual parts of an image may have little meaning on their own, but when combined the
whole takes on a perceived form.
o Figure-ground principle: figures in our environment tend to stand out against a background
Ex) text in front of you is a figure set against a background, but you may also think the
letters are against the background of the page.
Proximity: helps us group items together.
o Similarity: can be experienced by viewing the intermixing of sports fan from opposing teams,
which typically yields distinct patches of crowd wearing similar clothing.
o Continuity (good continuation): perceptual rule that lines and other objects tend to be
continuous rather than abruptly changing direction.
Closure: the tendency to fill in gaps to complete a whole object
Top-down processing: occurs when prior knowledge and expectations guide what is perceived.
o Ex) walking into a crowded room to locate a friend because you have a face in mind, and you
know what to look for
Bottom-up processing: constructing a whole stimulus or concept from bits of raw sensory
o Ex) driving a car in a foreign country for the first time would engage this. Attempt to make
sense of what different traffic signals/road signs mean.
The way we perceive the world is a combo of both top-down and bottom-up processing.
Parallel processing: simultaneous use of top-down and bottom-up processing.
o Ex) it's what allows us to attend to multiple features of what we sense.
Attention and Perception
Selective attention: involves focusing on one particular event or task
o Ex) studying, driving without distraction
Divided attention: involves paying attention to several stimuli or tasks at once.
o Ex) playing vid games and holding a convo
Inattentional blindness: failure to notice clearly visible events or objects because attention is
The Human Eye
How the Eye Gathers Light
Light refers to radiation that occupies a relatively narrow band of the electromagnetic spectrum.
Light travels in waves that vary in terms of 2 different properties:
o Wavelength: distance between peaks of a wave--differences in wavelength correspond to
different colors on the electromagnetic spectrum.
Long wavelengths: red
Short wavelengths: bluish color
o Amplitude: peaks of a wave give different experiences.
Low amplitude: correspond with dim
High amplitude: bright colors
o Hue: colors of the spectrum
o Intensity: brightness
o Saturation: colorfulness or density 22
Structure of the Eye
Sclera: white, outer surface of the eye
Cornea: clear layer of the eye that covers the front portion of the eye. Contributes to the eye's ability
Pupil: regulates amount of light that enters by changing its size; dilates to allow more light to enter
and constricts to allow less light into the eye.
Iris: a round muscle that adjusts the size of the pupil; it also gives the eyes their characteristic color
Lens: clear structure that focuses light onto the back of the eye.
The Retina: From Light to Nerve Impulses
Retina: lines the inner surface of the eye and consists of specialized receptors hat absorb light and
send signals related to the properties of light to the brain
o Photoreceptors: specialized receptors of the retina
Cones: photoreceptors that are sensitive to the different wavelengths of light that we
perceive as color
Fovea: central region of the retina that contains highest concentration of cones.
Rods: photoreceptors that occupy peripheral regions of the retina; they are highly
sensitive under low light levels 23
Dark adaptation: process by which rods and cones become increasingly sensitive to light under
low levels of illumination.
o Explains why we can gradually see more objects at very low light levels
Optic nerve: cluster of neurons that gather sensory information, exit at the back of the eye, and
connect with the brain.
o Blind spot: space in the retina hat lacks photoreceptors 24
Common Vision Disorders
Eye is delicate and sensitive; prone to various problems.
Affect the ability to focus
o Nearsightedness: occurs when the eyeball is slightly elongated, causing the image that the
cornea and lens focus on to fall short of the retina.
Can see objects relatively close up but have difficulty focusing on distant objects
Farsightedness: if the length of the eye is shorter than normal from front to back.
Image is focused behind the retina
They can see distant objects clearly but not those close by.
The Visual Pathways to the Brain
Optic chiasm: point at which the optic nerves cross atht eh midline of the brain
o For each optic nerve, about half of the nerve fibres travel to the same side of the brain, and
half of them travel to the opposite side.
o Fibres of the optic nerves connect with the visual area of the thalamus at a region called
lateral geniculate nucleus (LGN)
LGN sends messages to the visual cortex where the complex processes of visual
Feature detection cells: respond selectively to simple and specific aspects of a stimulus,
such as angles and edges.
o From the visual cortex, info about shapes and contours are sent to other cortical areas:
Ventral stream: a pathway extending from the visual cortex to the temporal lobe and is
where object recognition occurs.
Dorsal stream: extends from the visual cortex to parietal lobe of the cortex and is where
depth and motion are perceived.
Perceptual constancy: ability to perceive objects as having constant shape, size, and color despite
changes in perspective.
o Our ability to make relative judgements about shape size and lightness makes this possible
Shape constancy: judging the angle of the object relative our position
Color constancy: allows us to recognize an object's color under varying levels of illumination
o Ex) bright, red car recognized as bright red in shade or full sunlight
Size constancy: based on judgements of how close an object is relative to one's position as well as
to the positions of other objects.
Facial Recognition and Perception
We have natural inclination to perceive faces. It is the most importance source of social info.
Prosopagnosia: face blindness. Can't recognize the face
o People with this are able to distinguish among faces even if they are unaware that they are
Depth Perception 25
Every image that hits the retina is two dimensional. Depth occurs in the brain.
Binocular depth cues: distance cues based on differing perspectives of both eyes.
o Convergence: a type of binocular depth cue that occurs when the eye muscles contract so that
both eyes focus on a single object.
Ex) as you track an object moving toward you, such as your fingertip towards your
nose, your eyes move inward.
Retinal disparity (binocular disparity) : difference in relative position of an object as seen by both
eyes, which provides information to the brain about depth.
Some people have stereoscopic vision: overlapping visual fields
Monocular cues: depth cues we can perceive with only one eye.
o Accommodation: takes place when the lens of your eye curves to allow you to focus on
Motion parallax: another monocular depth cue; used when you or your surroundings are in
Ex) you sit in a moving vehicle and look out of the passenger window, you will notice objects
closer to you, such as the roadside, parked cars, and nearby buildings appear to move rapidly
in the opposite direction of your travel.
Psych at the Artist's Studio
Linear perspective: parallel lines stretching to the horizon appear to move closer together as they
travel farther away. This effect can be seen in the narrowing of the streets and the converging lines
of the sidewalks and top of the building in the distance.
Interposition: nearby objects block our view of far-off objects, such as the umbrellas blocking the
view of buildings behind them
Light and shadow: shadow cast by an object allows us to detect both the size of the object and the
relative locations of objects. Closer objects reflect more light than far-away objects.
objects that are coarse and distinct at close range become fine and grainy at
Height in plane: objects higher in our visual field are perceived as farther away than objects low in
our visual field.
Relative size: two objects in an image are known to be the same actual size. 26
One experience of color is based on how our visual system perceives different wavelengths on the
Three-types of cones initially identified in the 18th century by [thomas young] [hermann von
helmholtz] and these cones allow us to perceive many colors on the spectrum.
maintains that color vision is determined by
Trichromatic theory (young-helmholtz theory):
three different cone types that are sensitive to short, medium, and long wavelengths of light.
Negative afterimage: you see one color after another color is removed.
o We see color in terms of opposites.
Opponent-process theory: states that we perceive color in terms of opposite ends of the spectrum:
red to green, yellow to blue, white to black.
Sounds and Structures of the Ear:
Hearing: inform you about the nature of the sound source 27
Sound waves: changes in mechanical pressure transmitted through solids, liquids or gases. They
have two important characteristics:
o Frequency: wavelength measured in hertz (Hz), number of cycles a sound wave travels per
o Pitch: perceptual experience of sound wave frequencies.
High frequency, short wavelengths/high pitch: low-frequency
Low-frequency: bass guitar.
o Amplitude: determines loudness.
Human Ear 28
Outer, middle, inner regions
Pinna: outer region that helps channel sound waves to the ear and allows you to determine the
source or location of a sound
Auditory canal : extends from pinna to the eardrum
Ossicles (hammer, anvil, stirrup): three tiny moveable bones.
o Eardrum attaches to these bones
Cochlea: fluid-filled membrane that is coiled in a snail-like shape and contains the structures that
convert the sound into neural impulses.
Perception of Sound
Sound Localization: Finding the Source
Sound localization: process of identifying where sound comes from.
o Handled by a midbrain structure called inferior colliculus
Two ways we localize sound 29
o We take advantage of the slight time difference between a sound hitting both ears to estimate
the directio nof the source.
o We localize sound by using differences in the intensity in which sound is heard by both ears
Theories of Pitch Perception
High frequency sounds stimulate hair cells closest to ossicles
Lower frequency sounds stimulate hair cells toward end of cochlea
Place theory of hearing: states that how we perceive pitch is based on the location along the basilar
membrane that sound stimulates
Ex) as you snap the rope, high-frequency waves occur closer to you, but then become
progressively smaller towards end of the rope.
Frequency theory: perception of pitch is related to frequency at which the basilar membrane
Hearing sounds exceeding 1000 Hz
Volley principle: groups of neurons fire in alternating fashion.
Primary auditory cortex: a major perceptual center of the brain involved in perceiving what we
Deaf: hearing loss, ranging from hard-of-hearing to completely deaf.
Conduction hearing loss: results when any of the physical structures that conduct sound waves to
the cochlea are damaged.
Sensorineural hearing loss: results from damage to the cochlear hair cells (sensory) and the neurons
composing auditory nerve (neural).
False -- most deaf people would not prefer to gain ability to hear.
False -- most deaf people recognize their condition as a disability.
True -- signed, gestural languages are fundamentally the same as spoken languages.
Touch and the Chemical Senses
Sense of Touch
How we Perceive Touch
Sensitivity or acuity can be tested using the two-point threshold test.
Regions with high acuity ex) fingertips, can detect two separate but closely spaced pressure
points of the device,
o whereas less sensitive regions such as lower back will perceive the same stimuli as only one
Fingertips, palms, lips are sensitive to touch
Haptics: active, exploratory aspect of touch sensation and perception. 30
o Active touch: feedback.
Ex) fingertips can help you determine whether an object is the appropriate shape and
can detect bruising or abnormalities that make "fruits" unsuitable.
o Tactile agnosia: recognizing objects by haptics hampered by damage to the somatosensory
Kinesthesis: sense of bodily motion and position.
o Muscles, joins, limbs, joitns to the brain
Kinesthetic sense allows you to hold it with enough resistance to avoid dropping it
Nociception: activity of nerve pathways that respond to uncomfortable stimulation
o Skin, teeth, cornea, and internal organs contain nerve endings called nociceptors
Nociceptors initiate pain messages
Two types of nerve fibers transmit pain messages
Fast fibres: sharp, immediate pain
o Slow fibres: chronic, dull pain
Gate-control theory: explains our experience of pain as an interaction between nerves that transmit
pain messages and those that inhibit these messages.
o Ex) if you stub your bare toe, rubbing the area around the toe may alleviate some of the pain
bcos large fibres carrying the message about touch inhibit the firing of smaller fibers carrying
o Cells in the spinal cord regulate how much pain signaling reaches the brain.
o Spinal cord is a neural gate that pain messages must pass through
Phantom Limb Sensations
Phantom limb sensations: frequently experienced by amputees, who report pain and other
sensations coming from absent limb
Mirror box therapy is a useful application used in clinical settings to help reduce phantom pain in
people who have lost limbs.
The Chemical Senses
The Gustatory System: Taste
Gustatory system: functions in the sensation and perception of taste
o Food and drink
Certain parts of the tongue have tastebuds
Papillae: visible small bumps containing receptors for taste.
o Lined with taste buds
o Gustatory cortex: deep-seated structure located in the interior of the cortex
o Secondary gustatory cortex: processes the pleasurable experiences associated with food.
Primary taste: salty, sweet, bitter and sour.
Umami: savoriness; taste associated with seaweed, MSG, protein-rich foods.
Supertasters: especially sensitive to bitter tastes 31
Olfactory System: Smell
Olfactory system: involved in smell---the detection of airborne particles with specialized receptors
located in the nose.
Olfactory epithelium: thin layer of cells that are lined by sensory receptors called cilia
Cilia: tiny hair-like projections that contain specialized proteins that bind with the airborne
molecules that enter nasal cavity.
Transmit msgs to neurons that converge on olfactory bulb; brains central region for
Limbic system: emotion
Developing Preferences for Flavors
Infants tend t prefer the flavors of the foods consumed by their mothers during gestation.
Chapter 5: Consciousness
Consciousness – a person’s subjective experience of the world and mind
Humans and animals have biological rhythms that are adapted to the cycles in the environment
o Ex: Animals hibernating in the winter
Circadian rhythms are roughly 24 hour cycles in the physiological processes of living beings
o i.e. the tendency to be asleep or awake at specific times, feel hungrier at certain times, or
even concentrate better at certain times
o Our circadian rhythm are regulated by daylight interacting with our nervous and
endocrine (hormonal) systems
o One of the key brain structure in this process is the suprachiasmatic nucleus (SCN) of
the hypothalamus. Cells in the retina of the eye relay message about light levels in the
environment to the SCN. The SCN, then communicates signals about light levels with the
pineal gland. The pineal gland releases a hormone called melatonin, which peaks in
concentration at nighttime and is reduced during wakefulness.
Light is the primary stimulus regarding the human circadian rhythm
For some people this system is disrupted. Ex: Blind people cannot send
light signals from the retina to the SCN and pineal gland. Therefore, the
circadian rhythms do not synchronize to day-night cycles but can be
adjust by using melatonin doses
o Circadian rhythms change with age
Generally, people will experience a change in when they prefer to sleep
People have high alertness and cognitive functioning during their preferred time
Stages of Sleep
Sleep has rhythms
Polysomnography refers to a set of objective measurements used to examine physiological
variables during speech 32
Sleep cycles are defined by the electroencephalogram (EEG), a device that measures brain
o The output is a waveform
Waves can be described by their
Frequency - # up-down cycles every second
Amplitude – Height and depth of the up-
o Beta waves – high frequency, low-
amplitude. They are characteristic of
wakefulness. Their irregular nature
reflects the bursts of activity in
different regions of the cortex, and
they are often interpreted as a sign
that a person is alert.
o Alpha Waves – As an individual shifts into sleep, the waves
become slower, larger and more predictable. Signal that a person
may be daydreaming, meditating, or starting to fall asleep
o EEG signals during sleep move through four
1. Stage 1: Brain waves slow down and become
higher in amplitude (theta waves). Breathing,
blood pressure, and heart rate all decrease as an
individual begins to sleep. Lasts about 20
2. Stage 2: After 10 to 15 minutes, the sleeper
enters stage 2, during which the brain waves
continue to slow. Includes sleep spindles and k
non- complexes which are periodic bursts of EEG
REM activity. Evidence suggests these busts may play
a role in helping maintain a state of sleep and in
the process of memory storage. As stage 2
progresses, we respond to fewer and fewer
external stimuli such as lights and sounds.
3. Stage 3: Brain waves continue to slow down
and assume a form called delta waves
4. Stage 4: Deepest stage of sleep during which
the sleeper will be difficult to awaken.
After an hour after falling asleep, we reach the end of our first stage
4 sleep phase. At this point, the sleep cycle goes in reverse and we move back toward stage 1
patterns. We do not go all the way back to stage 1, we move into a unique stage called REM sleep
5. REM: Last about 10-20 minutes and we have an irregular EEG, increased heart
rate, respiration, bodily movement, rapid eye movement, and brain activity. This
stage is when dreams occur. Time spent in each REM cycle tends to increase
throughout the night. It is also known as paradoxical sleep because the EEG
eaves appear to represent a state of wakefulness even though we are asleep. At 33
the end of the first REM phase, we cycle back toward deep sleep stages and back
into REM sleep again ever 90-100 minutes.
Critical for a good night’s sleep
When deprived of sleep, we experience REM rebound, where our brains
spend an increased time in REM-phase sleep when given the chance.
Loss of REM sleep is worse that the amount of sleep lost.
Five basic stages of whole sleep cycle
1. Last about 5 min. During this transition stage, brain waves become slower and irregular.
2. Last around 10-20 minutes. Have regular EEG, spindles, and k complexes appear. Less than 50% of sleep is
3. Brain waves continue to slow down and assume the form of delta waves. Short transition phase of slow
wave sleep made up 20-50% delta waves.
4. Run 15-30 minutes. In this stage, we have less the 50% of delta waves. Represents deep restorative sleep.
We spend about 30 minutes here the first time we cycle through it with less time spent here as night
Then we cycle back into stage 3 and 2 before entering stage 5.
5. REM. Last about 10-20 minutes and we have an irregular EEG, increased heart rate, respiration, and brain
activity. This stage is when dreams occur. Time spent in each REM cycle tends to increase throughout the
Then we cycle through 2, 3,4 and we repeat the 90-minute cycle about 5 times in the night.
Why do we need sleep?
1. Restore and Repair Hypothesis: Idea that the body needs to restore energy levels and repair any
wear and tear on the body from the day’s activities.
o Sleep is a physical and psychological necessity
o Lack of sleep can lead to cognitive decline, emotional disturbances, and impairs
functioning of the immune system
o This theory does not account for reason why we sleep
If we have a more active day, we may need more sleep despite what the restore
and repair theory suggest
2. Preserve and Protect Hypothesis: Suggests that two more adaptive functions of sleep are
preserving energy and protecting the organism from harm
o To support this, researchers note that the animals most vulnerable to predators sleep in
o The "Preservation and Protection" theory holds that sleep serves an adaptive function. It
protects the person during that portion of the 24-hour day in which being awake, and
hence roaming around, would place the individual at greatest risk.
o Primary function of sleep is to conserve energy and protect oneself from predation
There are multiple reasons why we sleep. Research shows it is combination of restoration and repair, and
preservation and protection. 34
Sleep Deprivation and Sleep Displacement
Sleep Deprivation: Occurs when