AY18/19 SEM1 PL1101E Eunice Pang
Chapter 1 The Science of Mind
LO1: Explain the subject matter that psychologists study, addressing the meaning of mind and psychology’s role as a hub science.
LO2: Analyze the respective contributions of philosophy and the physical sciences as the “roots” of modern psychology.
Psychology
● is the objective/scientific study of the mind (behavior and mental processes such as thought and emotion)
● uses scientific methods and objective measurements to test hypotheses about the mind and how it works
● is just over 100 years old
● was created through combining features from two fields of study that already existed (philosophy & natural sciences)
LO3: Compare and contrast the early movements in psychology –
structuralism, Gestalt psychology, functionalism, behaviorism,
psychodynamic theory, and humanism – in terms of leading figures, core principles, and contributions to modern psychology.
| Person or group | Core principle |
| Ancient Greek philosophers | Observations can be accounted for by natural, not supernatural, explanations. |
| British empiricists
(i.e. John Locke) |
Knowledge is the result of experience. (humans start with a blank-state of mind – mind-body
problem) |
| Ancient physicians | The brain is the source of the mind. |
| 17th- and 18th-
century natural scientists |
Discoveries about sensation and movement showed that the mind was physical. |
| Gustav Fechner
(1801 – 1889) |
To identify the softest sound that a person could hear by randomly presenting sounds of different intensities to which a participant would respond “yes” or “no.” When the “yes” responses
reached 50%, Fechner concluded that the sound was within the range that the human ear could detect. |
| Hermann von
Helmholtz (1821 – 1894) |
Studies of reaction time (nerve conduction) reinforced the idea of the mind as physical |
| Wilhelm Wundt
(1832 – 1920) |
◆ 1st experimental psychologist
◆ Father of Structuralism ◆ Student was Edward Titchener ◆ Conducted the first documented psychology study in 1879, asking how quickly research participants could press a telegraph key after hearing a ball drop ◆ BREAKING DOWN INTO PARTS |
| ◆ The mind could be broken down into the smallest elements of mental experience (sensations, emotions)
◆ Using introspection to understand human experience ◆ Subjective experience matters more than the object |
|
| Gestalt Psychology | ◆ Founded by a group of early 20th-century German psychologists, including Kurt
Koffka, Max Wertheimer, and Wolfgang K ◆ Believed that the breaking down of a “whole” perception into its building blocks would result in the loss of some important psychological information ◆ Example: ABC & 121314 |
| William James
(1842 – 1910) |
◆ Father of Functionalism
◆ Viewed behaviour as purposeful because it led to survival ◆ The value of an activity depended on its consequences |
| Sigmund Freud
(1856 – 1939) |
◆ Psychodynamic theory emphasized the
existence of a vast, unconscious mind (“id”) that was separate from conscious awareness, but very powerful. ◆ his psychodynamic theory and its applications to the treatment of psychological disorders dominated much of psychological thinking for the first half of the 20th century ◆ “id” is violent, selfish, obsessed with sex, and socially unacceptable. ◆ Goal of psychodynamic therapy is to identify the unconscious needs behind people’s conscious thoughts and behaviors. ◆ Unscientific methods of study, work discredited |
| Humanistic
Psychology (1960s, when it was mainly behaviourism vs Freud’s //Structuralism died, Functionalism & Gestalt became indistinct SOTs) |
◆ led by Abraham Maslow (1908 – 1970) and Carl Rogers (1902 – 1987)
◆ counteracting behaviourism (internal v impt for understanding behaviour, not only external) & Freud’s psychodynamic theory (human nature is inherently good & ppl desire self-improvement) ◆ people are innately good, are motivated to improve themselves, and behave badly only when corrupted by society ◆ Abraham Maslow introduced a major theory of motivation ◆ Carl Rogers developed client-centered |
hler| therapy: replaced “patients” with “clients”
> Influenced communication, group process, parenting & politics |
|
| Behaviourism | ◇ Focused on observable, measurable, explicit behaviours
◇ restricted their research to studies using animals & drew parallels between their observations of animals and their assumptions about human behaviour ◇ Ivan Petrovich Pavlov (1849–1936): discovered Classical/Pavlovian Conditioning – dogs salivated to arrival of handler, not food itself. Had associated/linked these signals to food, giving survival advantage > Classical conditioning appears in primitive organisms & also very frequently in humans ◇ John B. Watson (1878–1958) restricted psychology to the study of observable behaviours & changed the American advertising industry ◇ Edward Thorndike (1874–1949) proposed the law of effect, which suggested that behaviours followed by pleasant or helpful outcomes would be more likely to occur in the future, whereas behaviours followed by unpleasant or harmful outcomes would be less likely to occur. ◇ B. F. Skinner (1904–1990) was interested in the effects of consequences on how frequently behaviours were performed. > Believed that psychology didn’t benefit from consideration of consciousness/internal mental states > reduced his study of behaviour to the actions of rats and pigeons in adapted cages (Skinner boxes) > generalized the behaviour of rats and pigeons to that of complex human behaviour > hugely benefitted quitting smokers/treatment of autistic kids |
| Cognitive Psychology | ◇ Ulric Neisser (1928–2012)
◇ Covers private internal mental processes that can be studied scientifically – information processing, thinking, reasoning, & problem solving ◇ Alan Newell (1927–1992) & Herbert Simon (1916–2001) wrote ground-breaking artificial |
| intelligence programs using human
information processing as their model. |
The Five Perspectives of Psychology
Biological psychology (behavioural neuroscience)
● focuses on the relationships between mind and behaviour & their underlying biological processes (genetics, biochemistry, anatomy, physiology)
● asks how our evolutionary past continues to shape our behaviour
Evolutionary psychology
● how our physical structure and behaviour have been shaped by their contributions to our species’ survival (see William James’ Functionalism)
● our current behaviour exists in its present form because it provided some advantage in survival and reproduction to our ancestors
Cognitive psychology
● focuses on the process of thinking/processing of information
● storage and retrieval of memories
Developmental psychology
● explores the normal changes in behaviour that occur across the life span.
Social & personality psychology
● describes the effects of the social environment (social and cultural diversity) & individual differences on the behaviour of individuals
● behaviour varies around averages and that individual differences often interact with environments
● Social: how psychological processes are influenced by interactions with other people
● Personality: how psychological processes differ from person to
person
Clinical psychology
● seeks to explain, define, and treat psychological disorders
● promotion of general well-being & health
For example, how might each of the perspectives in psychology approach the topic of physical aggression? (Each of the points below is a consistent research finding.)
● Biological: aggression is associated with low levels of serotonin.
● Evolutionary: we aggress against people who challenge our status.
● Cognitive: we learn to be more aggressive when we see aggression rewarded.
● Social: we are more aggressive when we are anonymous and unaccountable.
● Developmental: aggressive behavior decreases sharply from the mid-20s on.
● Clinical: aggressive individuals tend to have low impulse control.
● Personality: aggressive people tend to have very high self-esteem.
Integration of psychology’s 5 major perspectives
single perspectives are insufficient for fully describing and explaining psychological phenomena
psychological processes can often be understood best by
integrating knowledge gained from a variety of perspectives
Psychology as a “hub” science
o Kevin Boyack and his colleagues generated a map of the sciences but used reference lists in journal articles instead of friendship
networks.
o Their analysis shows that psychology is one of the seven major hub sciences, with strong
connections to the medical sciences, the social sciences, and education.
Chapter 3 The Evolving Mind (Nature & Nurture)
Genes being turned on or off due to ongoing interactions with the environment.
example: Agouti gene in normal brown furred mice – turned on when
pregnant mother ate food containing bisphenol A (BPA), producing yellow furred, obese mice.
Earlier scholars, especially Francis Galton (1869), debated the relative contributions of nature or nurture to a particular type of behaviour –
nature verus nurture
Genotype: a pair of alleles which interacts with the environment to produce observable characteristics (phenotype)
Gene: a segment of DNA containing info to produce protein
Relatedness: probability that two people share copies of the same allele from a common ancestor
Parent/sibling = ½ First cousin = 1/8
Haemophilia
◇ Is a sex-linked characteristic (more frequent among males)
◇ Disease where blood fails to clot
◇ Recessive allele found only on X chromosome
◇ XhXh – haemophilic female
◇ XHXh – carrier female
◇ XhY – haemophilic male
Subfields of genetics
| Branch of
Genetics |
Topic | Example |
| Behavioural genetics | strength of genetic influences on a
particular behaviour |
Variations in loneliness across the population appear to be strongly influenced by genetics. |
| Molecular
genetics |
Candidate genes:
genes that have a greater impact on a trait of interest than other genes |
Certain genes seem to impact loneliness more than others. |
| Functional
genomics |
Links between the global genome and particular traits | Genes may be expressed
differently in lonely & nonlonely individuals |
| Gene–
environment Interactions |
Candidate genes have different
effects in different situations |
Candidate genes seem to have
more impact on loneliness in some environments compared to others. |
Heritability
◆ the statistical likelihood that variations observed across individuals in a population are due to genetics.
◆ Takes into account both genetics & environmental factors
◆ always refers to populations, never to individuals.
◆ Example: no individual variation in the population in terms of the presence of a heart
heritability of having a heart = 0
◆ higher heritability in constant environments // lower heritability in variable environments
◆ Concordance rates: statistical probabilities that a trait observed in one person will be seen in another
Epigenetics
◆ refers to the reversible development of traits by factors that determine how genes perform.
◆ Epigenetic change occurs when factors other than the genotype produce changes in a phenotype, influencing gene expression.
◆ Genes can be turned on/off by internal signals
(hormones/neurochemicals) or external signals (diet/toxins)
◆ Highest to lowest rate of epigenetic change: by age – fetus, child, adult
◆ Factors: nutrition, disease-causing organisms, drugs, stress & environmental toxins
◆ Processes that produce lasting & reversible changes in gene
expression: ribonucleic acid (RNA) interference, RNA editing, histone modification, and DNA methylation
◆ Histones are protein structures around which your DNA is wound.
◆ DNA methylation occurs when a methyl group (one carbon atom bonded to three hydrogen atoms) is added to the DNA molecule = turns genes off
EVOLUTION
o descent with modification from a common ancestor
o artificial selection & natural selection
o Gregor Mendel (1822–1884) discovered ways to predict the inheritance of particular traits in his research on pea plants
Mechanisms
o Mutation
. an error that occurs when DNA is replicated
. advantageous mutant alleles spread through the population, disadvantageous disappear
o Genetic drift
. produces change from one generation to the next through chance or accident
. eg: Founder’s effect/bottleneck effect
o Migration
. occurs when organisms move from one geographical location to the next
. affect the survival of individuals and the frequency of certain alleles in the population
. phenotypical traits that are advantageous in one environment might be less so in another
Fitness: ability of one genotype to reproduce relative to other genotypes in a particular environment (eg. recessive sickle cell trait)
Adaptation: evolutionary changes whereby a population becomes better suited to its environment (eg. light/dark moths)
The Contemporary Human Brain
o very new adaptation
o present brain size same as that of early Homo sapiens ancestors although present-day humans advanced in every way
Culture
o arise from socially transmitted knowledge
o provide practices, values, and goals that can be shared by groups of people
o case study: Waorani and Yanomam 
of the Amazon Basin.
o Fights between villages account for 30% of the deaths among Yanomam 
males and 54% of deaths among Waorani males
o Cultural traditions in the two groups have led to different patterns of interactions between aggression and reproductive success
o The Waorani tend to aggress against other villages at every encounter, not just during raids when resources are at stake
o Aggressive Yanomam 
men produce more children than less
aggressive Yanomam 
, but less aggressive Waorani men have more surviving offspring than aggressive Waorani
o A simple cultural distinction—the Yanomam 
practice of standing down for a period of time between raids, which is not a practice shared by the Waorani—appears to account for the differences
observed in the impact of aggression on reproductive success.
Chapter 4 The Biological Mind
Biological Psychology
o Also known as behavioural neuroscience
o Is the scientific study of the reciprocal connections between the
structure and activity of the nervous system & behaviour and mental processes
o how physical structures relate to the mind and behaviour
o Biological changes influence behaviour & cognition
Cultural Neuroscience
o an interdisciplinary field that examines how cultural and biological mechanisms mutually shape human behaviour across phylogenetic, developmental, and situational timescales
o aka how genetics, brain structures, and cultures interact to shape behaviour
Humans, who lack impressive teeth or claws, formed groups to enhance the odds of their survival.
The mind’s perceptions of the social environment can affect biological processes that are important to health and survival:
| Socially INcluded | Socially EXcluded | |
| Greater risk of | Contagious viruses
from close contact with ppl |
Bacteria from cuts & scratches |
| Brain generate
hormonal signals for immune system to |
Gear up & protect body from viruses | Gear up & protect body from bacteria |
Dualism
o Proposed by René Descartes
o suggests that our mind is somehow different and separate from our physical being
Monolism
o field of biological psych & neurosciences (basically everyone) follow monolism
o refers to: the mind is what the brain does
early fails in biopsych
o Autopsy used since 3000 BCE
o Aristotle (384–322 BCE) mistakenly believed that the heart, not the brain, was the source of mental activity
o Phrenology (end 18th century): proposed that the pattern of bumps on an individual’s skull correlated with that person’s personality traits
and abilities
o Brain = muscle (??) that grew & specific areas will cause skull to bulge
o Can “read” personality traits from the bumps
o BUT correctly theorized that behavioural functions were localised in the brain
Contemporary approaches
| scientist | Worked on/discovered |
| Santiago Ramón
y Cajal (1852– 1934) |
microscopic level of nervous system |
| Camillo Golgi | was proven wrong (that the nervous system was a single, continuous network) by Ramón y Cajal who used Golgi’s invention, the microscopic stain, to
prove that the nervous system was made out of separate cells (Neuron Doctrine) |
| John Hughlings
Jackson (1835– 1911) |
◆ relationships btwn larger structures of the brain
◆ proposed that nervous system is organised as a hierarchy, with progressively more complicated behaviours being managed by more recently evolved and complex structures ◆ Example: People drinking alcohol
making
people start doing things that they will not typically do while sober |
Alcohol decreases the activity of parts of the brain involved with judgment and decision
Without the influence of these controls,Reductionism
. The explanation of complex things as sums of simple things
. BUT cannot understand complex phenomena by studying an
individual member’s behaviour bc large collections of simple things do not always behave in the same way simple things behave in
isolation
. At each stage (of complexity) entirely new laws, concepts, and generalizations are necessary
Central nervous system (CNS)
● Consists of brain & spinal cord ● Nerves encased in bone
Peripheral nervous system (PNS) ● 31 nerves branching out of CNS ● Nerves not encased in bone
Central Nervous System
HINDBRAIN
| structu
re |
location | function | damage
results in |
| medulla
oblonga ta |
Base of
brain, merging with spinal cord |
◆ Crucial part of brain
◆ Carries out involuntary functions (i.e. breathing, swallowing & heart rate) |
A quick
death |
| pons | above
medulla |
◆ management of sleep, arousal & facial expressions
◆ relays messages ◆ very necessary bc sensory messages can’t be transmitted to cortex without it ◆ regulates sleep-wake cycles |
| ◆ connects cerebellum to brain | |||
| cerebell
um |
◆ balance and motor coordination
◆ everyday voluntary tasks ◆ contains more nerve cells than the rest of the brain combined |
deficits in
language, cognition, perception, balance |
|
| midbrai
n |
Above
pons |
◆ involved in sensory reflexes, movement, and pain
◆ when endorphins are present in the periaqueductal gray, they decrease the strength of pain messages traveling to higher levels of the brain. |
|
| reticula
r formati on |
length of
brain stem from medulla to midbrain |
◆ management of levels of arousal
◆ cells firing fast = awake ◆ slow = deep sleep/unconsciousness |
SUBCORTICAL STRUCTURES
| structure | location | function | damage results in |
| thalamus | centre
of brain |
. input from sensory
systems reaches here first, then is forwarded to cerebal cortex . involved in memory and states of consciousness |
. Lesions results in profound
memory loss . Seizures during sleep |
| basal
ganglia |
large
structur es that cup the thalamu s |
. Involved in voluntary movement
. Forms complex circuits with motor structures in brainstem, thalamus & cerebral cortex |
. Parkinson’s
disease: initiation of voluntary movement difficult . OCD, ADHD: inadequate control of voluntary movement |
| hypothala
mus |
Tempora
l lobe |
. involved with motivation and homeostasis
. regulation of body functions such as temperature, thirst, hunger, biological rhythms, and sexual activities |
| hippocam
pus |
Tempora
l lobe |
. essential to the
formation of long-term memories . memories not permanently stored here . involved in the storage and retrieval of memories located elsewhere in the brain |
. profound
impairments in the ability to form new memories . intelligence, personality & memories of events that occurred before hippocampal damage remain intact |
| cingulate
cortex |
Forms a
fold of tissue on the inner surface of each cerebral hemisph ere |
. anterior cingulate cortex (ACC)
system tgt w hypothalamus
making, emotion, anticipation of reward & empathy. . posterior cingulate cortex (PCC)
|
|
| amygdala | One
deeply embedd ed in frontal portion of tempora l lobe in each hemisph ere |
. receives sensory
information (vision, hearing, and smell) . produces emotional and motivational output that is sent to the cerebral cortex. . Responds to both positive & negative stimuli . Best known for identifying, remembering, responding to fear & aggression |
. Do not show fear to usually fear-inducing things
. difficulty recognising expressions of fear . Stands closer to others than normal |
| nucleus
accumben s |
. Involved in the brain’s pleasure circuitry &
addiction . Related to sense of social |
forward two-thirds of CC
Participates in control of autonomic nervous
Deals w decision
memory and visual processing| inclusion: higher = more activity |
CEREBRAL CORTEX
● Is the thin layer of cells covering the outer surface of the cerebral hemispheres
● Thinking & sensory info processing (in cingulate cortex especially)
● Made up of 4 lobes
● Corticalisation: wrinkling of grey matter due to acquisition of knowledge over time
● Corpus callosum: a large bundle of nerve fibres connecting the two large cerebral hemispheres
Localisation of functions in the cerebral cortex
| sensory | processes incoming information from the sensory systems (i.e. vision/hearing) | Primary visual cortex | Occipital
lobe |
| Primary auditory cortex | Temporal
lobe |
||
| processes information about touch, pain, body position, and skin
temperature |
Primary
somatosensory cortex |
Parietal lobe | |
| motor | provides the highest level of voluntary control over movement | Primary motor cortex | Rearmost
portion of frontal lobe |
| associat
ion |
helps us form bridges between sensation and action, language, and abstract thought | Association cortex | Distributed
throughout the cortex |
Frontal lobe
o Broca’s area
■ Functions discovered by Paul Broca in 1860s
■ Participates in production of speech
■ Damage (of a stroke/tumor) = difficulty in speaking but comprehension of speech remains good
o Prefrontal cortex
■ Involved in the planning of behaviour, attention & judgement
■ Abnormalities account for psychological disorders (i.e. schizophrenia, ADHD)
o Alien hand syndrome
■ occurs when connections between the prefrontal cortex and the lower areas of the brain involved in movement are damaged
■ no effect on sensory feedback from the limb, such as touch and position
■ patients do not seem to have control over their affected limbs and are often unaware of the limbs’ activities
o Phineas Gage, 1848
■ Accident damaged areas of left frontal lobe
■ Outwardly normal in intelligence, speech, movement but was prone to angry outbursts & unreliability
o Frontal lobotomy
■ To reduce fear and anxiety in patients with serious psychological disorders
■ But they became impulsive & antisocial
o Orbitofrontal cortex
■ a part of the prefrontal cortex located just behind the bony orbits protecting the eyes
■ plays an important role in our emotional lives
■ damage = deficits in social behaviour & experience of emotion but retain intelligence, language, attention
■ i.e. patient E.V.R. experienced orbitofrontal damage during surgery for a tumour
■ no problems discussing moral dilemmas but faced enormous problems in making everyday decisions
o patients with antisocial personality disorder had around 11% less volume of prefrontal cortex compared to normal people
o individuals with APD/orbitofrontal cortex damaged …
■ fail to anticipate the emotional consequences of situations
■ unable to delay gratification
■ choose short-term benefits over long-term despite knowing
consequences
Occipital lobe
o located at the back of the brain
o home to the PVC
o PVC responds to basic info about the image (i.e. borders, colours, shading, movement)
o Pathway connecting to temporal lobe helps with recognition of objects
o Pathway connecting to parietal lobe helps with processing of movement of objects
Temporal lobe
o Home to PAC: process incoming sounds
o processes some higher visual system tasks: recognition of objects and the faces of familiar people.
o Damage to Wernicke’s area
■ speak fluently but make no sense
■ cannot comprehend speech
■ unaware of their deficits
Parietal lobe
o home to PSC
o damage = neglect syndrome: have difficulty perceiving part of their body or part of the visual field
o processes input on taste & higher visual system tasks: tells us how quickly something is moving toward us
Mirror Neurons
o discovered in monkeys by a team of Italian scientists (Di Pellegrino, Fadiga, Fogassi, Gallese, & Rizzolatti, 1992) using single-cell
recording
o fMRI done on humans found mirror “systems”
o helps us understand actions, emotions & intentions of others
Right & left brain
o Lateralisation: localization of a function in either the right or the left cerebral hemisphere
o Vision, sensation, movement on right side of the body are processed by left hemisphere
o Split-brain operation
■ In 1960s, surgeons cut patients’ corpus callosum and other
pathways connecting the right and left cerebral hemispheres to treat rare cases of life-threatening seizures
■ Succeeded in reducing/eliminating seizures, no changes in personality, intelligence, or speech
o Majority of people lateralise language to the left hemisphere (nearly all righthanded & 70% of lefthanded)
o Left hemisphere: mathematical computation, logical reasoning, positive emotions
o Right hemisphere: music functions, spatial information, intuition, the visual arts, negative emotions
Functions of lateralisation
o Provide ability to multitask – survival advantage
o Might have made language possible
o might account for human’s vulnerabilities for schizophrenia
Peripheral Nervous System
The somatic nervous system
o transmits commands for voluntary movement from the CNS to the muscles and brings sensory input back to the CNS for further
processing
o these functions are carried out by:
■ 31 pairs of spinal nerves serving the torso and limbs
■ 12 pairs of cranial nerves serving the head, neck, and some internal organs
The autonomic nervous system (control of glands and organs)
o Sympathetic nervous system
■ Prepares the body for situations requiring the expenditure of energy
■ i.e. heart racing, rapid breathing, pale face, sweaty palms – to provide muscles with resources they need for flight-or-fight
reaction
o Parasympathetic nervous system
■ Directs the storage of energy
■ Controls the glands & organs at time of relative calm
■ allows you to store nutrients, repair your body, and return the activities of internal organs to baseline levels
■ both S & PS usually have antagonistic effects on the organs they serve and are designed to alternate their activities (arousal vs relaxation)
o Enteric nervous system
■ consists of nerve cells embedded in the lining of the gastrointestinal system
■ contains as many nerve cells as are found in the spinal cord
■ communicates with the endocrine system to ensure the release of chemicals essential to digestion
■ some functions result in conscious perceptions: gastrointestinal pain, hunger, satiety
■ others operate below the threshold of conscious awareness: having a “gut feeling”
■ disturbances of the enteric environment might contribute to the development of autism spectrum
– enteric system is the source of 95% of the body’s serotonin
– individuals with autism spectrum disorder show higher than normal levels of serotonin in their blood & experience gastric distress often
The endocrine system
o made out of glands that release hormones into blood
o responds to input from the nervous system and from the hypothalamus in particular
o especially involved with arousal, metabolism, growth, and sex.
o Important glands: pineal gland, the pituitary gland, the thyroid gland, the adrenal glands, the islets of Langerhans, and the ovaries in
females and testes in males.
Neurons
o Process and transmit info
o Similar to other cells in basic function (metabolic & manufacturing protein)
o Soma (cell body) – contains cell nucleus
o Dendrites – receive input from other neurons
o Axons – send output to other neurons
Myelin
o Myelinated axons speed up transmission (pain signals reach brain faster)
o Unmyelinated axons slower transmission (dull, achy pain signals)
Glia
o Wraps around axons to form myelin
o Make it possible for neurons to do their job effectively
o Some provide a structural matrix for neurons, ensuring that they stay in place
o Some are mobile, allowing them to move to a location where neurons are damaged to clean up debris
o Forms a blood-brain barrier
o Damage to glia in brain + spinal cord = form scar tissue, repair of nerves inhibited (permanent)
o Damage to glia in PNS = don’t form scar tissue, helps damaged axons regrow
Neural Signalling
Electrical Signalling
o Squid axon used
■ placed in a tub of seawater, which has a chemical composition similar to the fluid surrounding our body cells
■ can be as much as 1 millimeter in diameter, large enough to see with the naked eye
■ large enough that you can insert a recording electrode into its interior without disrupting its function
o Resting potential: interior of neuron negatively charged compared to exterior (usually -70)
o Depolarized: difference between the electrical charges of the
extracellular and the intracellular recordings is decreasing, reaching action potential
o Channels in the neural membrane open and positive sodium ions flow in, depolarizing the axon
o When a neuron is depolarized by sufficient input, it reaches a threshold for producing an action potential (inevitable)
o Near peak of action potential, positive potassium ions flow out of membrane into extracellular fluid
o Hyperpolarized (moving away): … increasing
o End with refractory period & rest period
o Propagation: duplication of electrical signal down length of axon to axon terminal
o Unmyelinated axons slower at transmission bc takes time to keep duplicating action potentials & use up a lot of energy to to clear up/return cell to resting stage
o Once action potential reaches axon terminal, neural communication system switches to chemical signalling
Chemical signalling
o Synapse: where two neurons communicate using neurotransmitters (chemical messengers), separated by extracellular fluid
o Excitation or inhibition of neuron, caused by interaction of neurotransmitter & receptor
Types of Neurotransmitters
o Acetylcholine (ACh): found at the neuromuscular junction, in the autonomic nervous system, and in the central nervous system
o Norepinepherine activity in brain & released by parasympathetic nervous system lead to arousal and vigilance
o Dopamine is involved with systems that govern movement, planning, and reward.
o Serotonin is involved with systems regulating sleep, appetite, mood, and aggression.
o Endorphins, short for endogenous morphine or morphine produced by the body, modify our natural response to pain.
Chapter 5 The Perceiving Mind (Sensation & Perception)
Sensation: brings info of outside world to the brain (passive reception of sensory info)
Perception: active interpretation of sensory input (requires knowledge, which requires experience, which is subjective)
Physical stimulus –>–>–>–>–>–>–>–> neural signal
transduction
Attention
o a narrow focus of consciousness
o unfamiliar, changing, or high-intensity stimuli affect our survival and have a high priority for our attention
o our sensory systems are particularly sensitive to changes in the environment
o sensory adaptation: a reduced response to an unchanging stimulus
o usually have divided/selective attention to prioritize selected info
o bottom-up processing: brain uses incoming signals to construct perceptions
o top-down processing: use knowledge gained from prior experience with stimuli to perceive them
Psychophysics
o methods of studying relationships between stimuli (physics part) & perception of those stimuli (psyche part)
o developed by Gustav Fechner
o absolute threshold: smallest possible stimulus that can be detected at least 50% of the time
o difference threshold: smallest difference between two stimuli that can be detected at least 50% of the time
o signal detection is a two-step process involving
– the actual intensity of the stimulus (which influences the observer’s belief that the stimulus did occur)
– the individual observer’s criteria for deciding whether the stimulus occurred
Participant response
Stimulus present
Stimulus absent
yes
no
false alarm
hit
correct rejection
miss
Vision
~50% of cerebral cortex processes visual info
| Corn
ea |
o clear surface at the front of the eye
o begins the process of bending light to retina |
| Pupil | o an opening formed by the iris |
| Iris | o brightly coloured circular muscle surrounding the pupil
o adjusts according to: ■ amount of light present in the environment (less light: dilated pupils) ■ signals from the autonomic nervous system (arousal: dilated pupils) |
| Lens | o clear structure behind the pupil that bends light to retina
o muscles attached to the lens allow us to focus on near/distant objects |
| Retin
a |
o layers of visual processing cells in the back of the eye |
| Blind
spot |
o at the optic disk where the blood vessels and axons leave the eye to form the optic nerve
o no rods & cones at this area |
| Fove
a |
o towards the middle of the retina
o responsible for central vision |
| Rods | o a photoreceptor specialized to detect dim light
o 90 million o more sensitive to light than cones o more common on periphery of retina – peripheral vision better in dim light o does not give colour, clear or sharp images |
| Cone
s |
o a photoreceptor in the retina that processes colour and fine detail.
o 4-5 million o function best under bright light o give sharp images in colour |
Visual pathways
o rods and cones absorb light
o axons in ganglion layer of retina cells leave the back of the eye to form optic nerve
o optic nerves cross the midline at the optic chiasm
– axons closest to the nose cross over to the other hemisphere
– axons on the outside proceed to same hemisphere
o axons after the optic chiasm are called optic tracts
o everything left of centre processed by right hemisphere, vice versa
o gives us significant advantage with sensing depth
o ~90% of optic tracts synapse in the thalamus, which sends info to:
o Amygdala
● which uses visual information to make quick emotional judgments, especially about potentially harmful stimuli
o PVC in occipital lobe
● begins processing of visual input
● responds to object shape, location, movement, and color
● sends info to parietal lobe (processes movement) &
temporal lobe (responds to shape, colour & recognition)
o The remaining connect with the:
– Hypothalamus
● where their input provides information about light needed to regulate sleep-wake cycles
– Midbrain
● which manage a number of visually guided reflexes, such as changing the size of the pupil in response to light
conditions
optic nerve -> optic chiasm -> optic tracts -> thalamus -> occipital lobe
Colour vision
Trichromatic theory
o a theory of colour vision based on the existence of different types of cones for the detection of short, medium, and long wavelengths
o 3 primary colours of light: red, green, blue
o 3 types of cones in the retina that respond best to short (blue), medium (green) or long (red) wavelengths
o our ultimate experience of colour comes not from the response of one type of cone but from comparisons among the responses of all three types of cones
o colour deficiency occurs when a person has fewer than the typical three types of cones
Opponent process theory
o have a red-green colour channel & a blue-yellow colour channel
o we cannot see a colour like reddish green or bluish yellow because the two colours share the same channel
o the channels are “opponent” or competing
o activity in one colour group in a channel reduces activity in the other colour group
overall:
– trichromatic theory provides a framework for the functioning of 3 types of cones in the retina
– opponent process theory fits observed phenomena neatly at higher levels of visual analysis.
– both theories help us understand colour vision but at different levels of the visual system.
Organization of sensory info according to Gestalt psychology
o born with built-in tendencies to organize incoming sensory information in certain ways
o simplifies the problem of recognizing objects
1. we spontaneously divide a scene into a main figure and ground:
assume that figure stands in front of ground, has more substance & shape
2. principle of proximity: objects that are close tgt tend to be grouped tgt
3. principle of similarity: similar stimuli are grouped tgt
4. principle of continuity: assume that points which form smooth lines when connected probably belong tgt
5. closure: when people see a complete, unbroken image even when there are gaps in the lines forming the image
6. simplicity: we will use the simplest solution to a perceptual problem
depth perception: the ability to use the two-dimensional image projected on the retina to perceive three dimensions
Monocular cues (a depth cue that only requires the use of one eye)
o Use of the linear perspective
– apparent convergence of parallel lines at the horizon
– Italian artists in 15th century
– Sega’s Zaxxon in 1982
– Pixar films/Avatar (2009)
o Texture gradients & shading
– Close objects have more texture
– Distant objects more blurry
– Shading/highlights to suggest curved surfaces
o Occlusion: the blocking of images of distant objects by closer objects
o Motion parallax
o Aerial perspective
o Relative size
o Interposition
Binocular cues (a depth cue that requires the use of both eyes)
o Retinal disparity
– predator species have eyes placed in the front of the head facing forward
– visual scenes observed by the two eyes are different and overlapping
– the differences between the images projected onto each eye are called disparities
– they provide information about the relative distance between two objects in the visual field
– advantage to predators to spot prey bc it allows us to spot tiny variations in the depths of objects in the visual field
– make an animal stand out against its background, even though it is well camouflaged
– used to identify camouflaged military equipment and counterfeit currency
– is imitated by cameras used to film 3D movies, which have two
lenses separated by about the same distance as our two eyes
Perceptual Constancies
o tendency to perceive objects as same even though their physical characteristics change
o size, shape, brightness, colour
Chapter 7 The Feeling Mind (Emotion & Motivation)
Emotion
o arousal, physical sensation & subjective feelings that occur spontaneously in response to stimuli
o is a brief combination of physical sensations that prepares an individual for action
o they are spontaneous, automatic responses to our ongoing perceptions and thoughts
o communicated to others through behaviours (facial expression, body language, gestures, and tone of voice)
o discrete vs continuous states of emotions
o mood: more general & lasts longer
Motivation
o driving behaviour toward a goal
primary motivations (homeostasis)
o innate needs (food, water…)
o drive-reduction theory: unconscious & aided by hypothalamus
intrinsic / extrinsic motivators
o extrinsic motivators like money – paying people for higher grades
o study done by Harvard University economist Roland Fryer shows that paying people to read/study works
o works for basic mechanical skills but anything remotely that involves even rudimentary cognitive tasks, grades slip
o different views & results as to whether extrinsic rewards can improve test scores
approach & avoidance theories of emotion
o approach things that give positive/desirable outcomes
o avoid things that give negative/undesirable outcomes Maslow’s hierarchy of needs & contemporary version
Theories of Emotion
James-Lange Theory Cannon-Bard Theory Schachter-
Singer Theory
James-Lange Theory
o William James & Carl Lange worked independently of each other but had similar descriptions.
o Perceived stimulus -> specific physical responses -> subjective feeling
o Contradicts with concept of catharsis: expressing the emotion will reduce the feeling
o Experiment where participants make faces then report “feeling” an emotion
o “psyching up”: New Zealand All Blacks performing the haka & feeling more aggressive
o But we’re not as good at interpreting our physical sensations as predicted by JLT
o Case study of the Capilano Canyon: men confused fear & sexual arousal
Cannon-Bard Theory
o Proposed by Walter Cannon, modified by Philip Bard
o Perceived stimulus -> Physical sensations & subject feeling occur simultaneously
o Explains Capilano Canyon results more effectively
o a person’s cognitive assessments of an emotional situation work independently of any physical sensations that might occur
Schachter-Singer Two-Factor Theory
o Stanley Schachter and Jerome Singer (1962)
o proposed a two-factor theory of emotion that adds an intermediate step between physical sensations and subjective feelings
o perceived stimulus -> conscious appraisal of surroundings / cognitive label -> subjective feeling
o failure to replicate experiment by other scientists, casts doubt
Appraisal Theory
o all about context / experience / subjectivity
o detection and assessment of stimuli with relevance for well-being, in eliciting emotion
o interpretation is a continuous process rather than a single decision about a stimulus
Chapter 8 The Adaptive Mind (Learning)
Reflexes are inevitable, involuntary responses to stimuli
Learning is a relatively permanent change in behaviour due to experience
Classical conditioning
Ivan Petrovich Pavlov (1849-1936)
CONDITIONED UNCONDITIONED
| – | something that must be
learned |
factors that are reflexive or that occur without learning |
| STIMULU
S |
an environmental event
whose significance is learned |
has innate meaning to the
organism & has the ability to elicit a response without prior exposure |
| RESPONS
ES |
learned reactions | don’t need to be learned; they
appear without prior experience with a stimulus |
Acquisition
o development of a CR
o must be CS and UCS must paired tgt in close proximity in time & paired every single time for faster learning
must be neutral stimulus
Extinction
o when association between CS and UCS broken: CRs disappear
o Temporal Delay: when CS appears more than 240s after UCS, ineffective acquisition
Spontaneous Recovery
o the reappearance of CRs following periods of rest between sessions of extinction training
Generalisation
o once a CR is successfully acquired, organisms often show a tendency to respond to stimuli that are similar to the CS
Discrimination
o allows us to make fine distinctions between the implications of stimuli
Little Albert & fear
o 1920 John B. Watson and Rosalie Raynor
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