Psyc
Definition: Scientific study of mind and behavior
Mind: private events happening inside of the person not seen by others.
Behaviour: public events, things said and done can potentially be observed by others.
Dualism vs Materialism
Dualism: Body/Mind
Descartes believed that the physical BODY was a container for the nonphysical thing called the MIND.
Materialism: Body=Mind
The mind is the activity of the brain
Realism vs Idealism
Realism: The perception of the physical world is produced entirely by sensory organ Information
Perceptions are a faithful copy of the “real world” and Perceptions of the world are like photographs
Idealism: Perceptions of the physical world are the brain’s best interpretation of the information that enters through our sensory apparatus.
Perceptions are less like photographs and more like paintings
Empiricism vs Nativism
Empiricism: All knowledge is acquired through experience
Nativism: Some knowledge is innate rather than acquired
Certain cognitive structures or abilities are hardwired into the brain/These innate capabilities form the foundation for further development and learning
Most modern psychologists embrace:
Materialism
Idealism
Nativism
History of psychology:
Psychology as a science began in 150 years ago
Late 1800s: Towards a science of the mind
Hermann von Helmholtz studied human reaction time
Stimulus: Sensory input from the environment
Reaction time: Amount of time between the onset of a stimulus and a person’s response to that stimulus
Goal: Estimate the length of nerve impulse
Psychologist’s first
Wilhelm Wundt
Published the fist textbook(1867)/Teached the fist course(1874)/Opened the first psychological laboratory(1879) in Germany
Structuralism (what is the mind like?)
Structuralism: Approach that attempts to isolate and analyze the mind’s basic elements.
Introspection (systematic self-observation): Analysis of subjective experience by trained observers
Functionalism (What is the mind for?)
Functionalism: Emphasized the adaptive significance of mental processes
Natural selection
The attributes that promote survival and reproduction are the ones that are passed along to the next generation
The early 1900s
Hysteria: Loss of function that has no obvious physical origin
Psychoanalysis (The mind does not know itself)
Psychoanalysis: Therapeutic approach that focuses on bringing unconscious material into conscious awareness/SW: Influence of the unconscious
Sigmund Freud/Focused on the unconscious
Behaviourism
Approach that restricted psychology to observable behaviour. Role of
reinforcement
September 11, 2025 (Chapter 1)
Behaviourism: The mind doesn't matter (John B. Watson)
Def: Approach to psychology that restricts scientific inquiry to observable behaviour.
Stimulus and response
Principle of Reinforcement: (Burrhus Frederick Skinner) Any behavior that is rewarded will be reparation and any behavior that isn't rewarded won't be repeated
Gestalt psychology: (Max Wertheimer)
Def: Psychological approach that emphasizes how mind created perceptual experience
We perceive the whole rather that the sum of the parts/Illusions
The study of memory: (Sir Frederic Bartlett)
Frederic wanted to examine why people remember things incorrectly, For example, people often remember what they had expected to read rather than what they had read
Our minds use their theories of how the world usually works to construct our memories.
Development psychology
Jean piaget: Examined the mind of children to understand their mistake
Stages of cognitive development:
Schemas: Mental frameworks or categories used to organize knowledge and experiences
Equilibration: new information is balanced with existing knowledge
Assimilation: incorporating new experiences into existing schemas
Accomodation: involves changing schemas to fit new information
Lev Vygotsky: Influential in education. Highlighted the role of social interaction in cognitive development and learning.
Social Psychology: Study of the causes and consequences of sociality
Kurt Lewin: Studied power within groups. Argued that behaviour is not a function of the environment but the person’s subjective construal of the environment.
Def: Construal means interpretation
Solomon Asch: Researched how people draw inferences about others. Conducted early studies of the “primacy effect”.
Cognitive revolution
Noam Chomsky: Argued that behaviourist principles could not explain language learning.
Universal grammar: Innate ability to acquire language
Cognitive psychology
Def: Study of human information processing
Evolutionary Psychology: (John Garcia)
Def: Study of the ways in which the mind has been shaped by natural selection
Biological predispositions influence how we can learn new associations
John G.: Every organism is evolved to respond to particular stimuli in particular ways
Studies of taste aversion
Neuroscience ‘’The mind is what the brain does’’
Cognitive neuroscience: Study of the relationship between the brain and the mind
(especially in humans).
Behavioural neuroscience: Study of the relationship between the brain and
behaviour (especially in nonhuman animals).
Functional MRI: Let scientist see brain regions are more or less active during different mental tasks
Cultural psychology: Study of how culture influences mental life
16 Sept, 2025
Everyday reasoning vs Scientific reasoning
Everyday reasoning: Personal observations or stories are commonly used to justify beliefs.
Scientific reasoning: Follows a structured and systematic process.
Inductive vs deductive reasoning
Inductive Reasoning
from specific observations → general conclusions
Deductive Reasoning
from general rules/principles → specific predictions
Flasifiability (Karl Pooper)
Scientific claims are capable of being falsified → Can be conceivably demonstrated to be untrue.
Emipricim: how to know stuff
Empiricism: Belief that accurate knowledge about the world can be acquired through observation. Importance of experience.
Dogmatism: Description of the tendency to cling to one’s beliefs.
Scientific Method
Scientific method: Procedure for using empirical evidence to establish facts.
Theory: Explanation of a natural phenomenon.
Hypothesis: Falsifiable prediction made by a theory.
Steps
1. Develop a theory.
2. Derive a falsifiable hypothesis from it.
3. Test that hypothesis by observing the world (gathering empirical evidence).
Can scientific theory be proven right?
Can't be proven right, but can be proven wrong with evidence
The art of looking
Empirical method: Set of rules and techniques for observation.
Kinds of methods:
Methods of observation: What people do
Methods of explanation: Why people do it
Observing: Use of one’s senses to learn about the properties of an event or an object.
Limitations
Inconsistent.
Incomplete.
Overcoming
Measurement
Description
Operational
Operational definition: Description of a property in measurable terms.
Construct validity
Construct validity definition: A construct is a theoretical concept that usually is not directly measurable
Extent to which the thing being measured adequately represents the concept it is intended to measure.
Key factors of a good detector
Detector: The thing you are giving out
Reliability:
Tendency for a measure to produce the same results whenever it is used to measure the same thing
How consistent it is
Power:
Ability of a measure to detect conditions specified in the operational definition.
How sensitive it is.
Measurement
Two steps:
Define property
Generate an operational definition that has construct validity
Detect property
Design an instrument that has reliability and power
Demand characteristics
Aspects of an observational setting that cause people to behave as they think someone else wants or expects.
Ways to avoid it
Observing people without their knowledge
Naturalistic observation:
Naturalistic observation definition: Technique for gathering scientific information by unobtrusively observing people in their natural environments.
Participant bias
Naturalistic observation: observing people in their natural environments.
Privacy: Responding in private / Anonymously.
Control: Measuring behaviours that are not under voluntary control (pupil dilation).
Unawareness: Avoid telling the real purpose of the study/misleading participants.
Ethical implications: Offered to withdraw data
Observer bias
Observer bias: Tendency for observers’ expectations to influence what they believe
they observed and what they actually observed
Descriptions
Population: Complete collection of people - rarely measured.
Sample: Partial collection of people drawn from a population.
Getting a representable sample
Diversity of the population: Sample should include various characteristics (e.g., age,
gender, ethnicity, education level) in the same proportions as they appear in the
population.
Random selection: Often used to ensure every individual of the population has an
equal chance of being selected.
Size: Large enough to capture key features of the population.
Making sense of data
Graphic representations → picturing the data.
Descriptive statistics → summarizing important characteristics of the data
Different graphics
Frequency distribution: Graphic representation showing the number of times in which the measurement of a property takes on each of its possible values
Central tendency
Mode = Median = Mean (To create the bell shape graph)
Skewed distribution
Data not symmetrically distributed around the mean
Most values are on one side, and the tail stretches out the other way.
Negativively Skewed (Left skewed)
Tail extends to the left (toward smaller values)
Mean < Median < Mode
Positively Skewed (right skewed)
Tail extends to the right (toward larger values)
Mode < Median < Mean
Variability
Range: Biggest value - smallest value in the distribution
High SD: High variability
Low SD: Low variability
Variable
Property that can have more than one value
Correlation
A mutual relationship or connection between two or more things.
Correlation direction: Either positive or negative.
Correlation coefficient
r ranges
+1.0 (perfect positive correlation)
0 (no correlation)
–1.0 (perfect negative correlation)
Positive correlation
Negative correlation
No correlation
Different strengths
Strong if r goes to 1 or -1
Weak if r goes to 0
Spurious correlations
Occurs when two variables are correlated but don't have a causal relationship.
Third variable problem
X - Y
Y - X
Z - X and Y
Experimentation
Technique for establishing the causal relationship between variables.
Independent (manipulated) and dependent (measured)
Steps of experimentation
Manipulate: Independent
Measure: Dependent
Compare: Measurements of conditions
Assigning of each group
Self-selection
Occurs when participants choose to participate in a study rather than being randomly assigned
Examples of Correlation vs Causation
People who exercise regularly report lower stress levels. (Correlation)
Patients with depression who received antidepressants improved more than those given a placebo (Causation)
Students who sleep (independent) more before an exam (dependent) tend to perform better. (Correlation)
People who spend more time practicing mindfulness report better focus and attention (Correlation)
Null hypothesis (H0) vs alternative hypothesis (H1)
Null hypothesis
No relationship between the variables
Predicts no effect or difference
Drinking regular coffee vs decaf has no effect on puzzle-solving time.
Alternative Hypothesis (H₁ or Ha)
There is a relationship between the variables
Predicts an effect or a difference
Non-directional: Drinking regular coffee vs decaf leads to a difference in puzzle-solving
time
Directional: Drinking regular coffee makes people solve puzzles faster than drinking
Decaf.
Statistical testing
Differences can happen by chance.
Determine whether any differences observed in our data are due to the manipulation or just due to random chance.
Statistical significance
Statistical significance: The difference is larger than what could reasonably be explained as a chance occurrence.
Calculate though inferential statistics
P-value (Probability of getting the results we observed if the H₀ hypothesis was true)
Statistically significant results: p < .05 (The probability (p) that the result would have been observed if random assignment had failed is less than 5%.)
Failure of random assignment: p > .05
P-value interpretation
Misinterpartation
P-value does not show if its true or false
Correct interpretation
Probability of observing the data you collected if H₀ was true
Small P-value
Results are unlikely to occur by chance
• Gives reason to reject H₀
Large P-value
Results are likely to occur by chance
We fail to reject H₀
Drawing conclusion
Internal Validity: Establish a causal relationship
External Validity: Generalized to the real-world
Errors in conclusion
Type I error:
Type II error:
Generalizability
N=population
n=sample
Generalizability Restriction: “In the People We Studied . . .’’
Sample selection
Case method: Studying a single individual
Random sampling: Every member of a population has an equal chance of being included in the sample (Not the same of random assignment)
Random assignment: A method used in psychology experiments to ensure every participant has an equal chance of being placed into any of the experimental groups
Non-random sapling: Acceptable if:
- The similarity between a sample and the population doesn’t matter.
- The similarity between the two is a reasonable starting assumption.
Replication
Experiment that uses the same procedures as a previous experiment but with a new sample from the same population.
Replication crisis
2015 study → over 60% of psych studies failed to replicate.
The ethics of research
The core principles, based on respect for human dignity, that all research involving human participants must follow
Respect for person (right to make decisions)
Concern for welfare (maximize benefits and reduce risks)
Be just (benefits and risks equally)
Informed consent
Verbal agreement to participate in a study made by an adult who has been informed of all the risks the participation may entail.
The participant can always withdraw from the study at any time with no penalty
Freedom from Coercion
Cant offer money for participants to participate
Risk and protection
Protection from harm: Researchers must use the safer method if there are more than one.
Risk-benefit analysis: Participants can’t be asked to accept a large risk (severe
pain, psychological trauma) or any risk that is greater than the risks of ordinary life.
Other considerations
Deception: Only use when Justified
Debriefing: Researchers should restore the participant state before they leave
Confidentiality: Private and personal information must be confidential
Research ethics board
Researchers must obtain approval from the REB before doing any research.
Respecting animals
The RS:
Replacement: Prove there is no alternative to using animals.
Reduction: Use the smallest number of animals possible.
Refinement: Procedures must minimize discomfort, infection, illness and pain.
Respecting truth
Results are reported truthfully on what was done and what was found.
Credit is fairly assigned.
Data is shared.
Chapter 3
25 Sept, 2025
Neurons
Cells in the nervous system
Communicate with one another to perform information processing tasks
Santiago Ramon and Cajal: Neurons do not touch each other
Synapse: region between axon of one neuron and dendrites of cell body of another
Components of the Neuron
1.Dendrites: Receive information from other neurons and relay it to the cell body.
2. Cell body (soma): Coordinates information-processing tasks and keeps the cell alive. Has a nucleus.
3. Axon: Transmits information to other neurons, muscles, or glands.
- Myelin sheath: Insulating layer of fatty material.
The synapse
Information transmitted by the presynaptic neuron to the postsynaptic neuron.
• Presynaptic membrane: of the axon of the transmitting neuron.
•Synaptic cleft: gap that separates the pre- and post-synaptic membranes.
•Postsynaptic membrane: dendrite or cell body of the receiving neuron.
Glial cells
Support cells found in the nervous system
• Astrocytes: regulate blood flow, regulate concentration of nutrients, ions and neurotransmitters
• Microglia: remove debris
• Oligodendrocytes & Schwann cells: wrap axons with myelin, which insulates them and speeds conduction.
- Oligodendrocytes: form myelin sheath in brain and spinal cord (Central Nervous System)
- Schwann cells: form myelin sheath for cells outside the brain and spinal cord (Peripheral Nervous System)
Neurons by function
Sensory neurons: Receive information from the external world; convey this information to the brain via spinal cord. Receive signals for light, sound, touch, taste, and smell.
Motor neurons: Carry signals from the spinal cord to muscles to produce movement. Often have long axons that reach to muscles at our extremities.
Interneurons: Connect sensory neurons, motor neurons, or other interneurons.
Not all Neurons look the same
The Electrochemical Actions of Neurons
Neurons use both electrical and chemical signals to communicate.
Electrical signal is conducted inside the neuron
Chemical signal is transmitted from one neuron to another
Electrical charge in the cell
All living cells have an electrical charge and are more negative on the inside than on the outside
Ions carry a small positive (+) or negative (-) charge
Ions can get in and out of the cell through small pores.
This creates the conduction of electric current within the neuron.
Membrane potential
Resting potential
• Neuron at rest is around –70 mV.
• Inside of the cell is more negative than outside (membrane is polarized).
• Maintained by ion channels and pumps.
Action potential (Depolarized)
The inside of the membrane becomes positively charged relative to the outside.
Inside and outside of cell
Inside:
Potassium (K+)
Proteins (-)
Outside:
Sodium (Na+)
Calcium (Ca+)
Chloride (Cl-)
Local potentials
Small changes in membrane potential
Make the membrane more positive (excitatory, cause depolarization) or more negative (inhibitory, cause hyperpolarization)
If enough depolarizing graded potentials add up, they can trigger an action potential.
The action potential
Depolarization: change (-70 mV) in a more positive direction.
Only occurs when the stimulation reaches a level or threshold.
Once the threshold is reached: “all-or-none”.
Refractory period: Time following an action potential during which a new action potential cannot be initiated.
How does the action potential happen?
The action potential occurs due to changes in the axon’s membrane channels.
Movement of sodium (Na+) into the cell.
During resting potential → Membrane channels for Na+ ions are closed.
When electrical charge across the cell membrane reaches the threshold → Na+ channels in the cell membrane open.
Na+ ions rush in causing electric charge changes from -70mV up to +40 mV
Refractory period
Na + channels are open for only a millisecond, then close automatically.
The action potential always spreads onward because the Na+ channels in each region are temporarily deactivated after the action potential passes over them.
Time following an action potential during which a new action potential cannot be initiated.
During this period the electrical and chemical balance of the neuron is restored.
Propagation of the action potential
Action potentials are regenerated along the axon
Travel in one direction
The myelin sheath
Saltatory conduction → speeds the flow of information down the axon
‘’All or nothing’’ domino video
If one falls all of them fall. However if there separated if 1 falls the other ones dont.
Chemical signaling: Transmission between neurons
Information passes between neurons through chemicals called neurotransmitters
Terminal buttons: Structures the branch out from the axon
Neurotransmitters:
Chemical messenger
Transmit signal across a synapse from one neuron to another target cell
Affect various physical and psychological processes
Small imbalances can affect behavior!
Receptors: Parts of the cell membrane that receive the neurotransmitters and initiate or prevent a new electrical signal
Synaptic Transmission
NT are stored in vesicles in the presynaptic neuron.
An action potential travels down the axon and arrives to the terminal.
The vesicles bind to the membrane.
NT are released into the synapse.
NT bind to receptors on the postsynaptic neuron, initiating a new action potential on that neuron
Receptors
NT and receptor sites act like a lock-and-key system.
Same NT binds to various kinds of receptors.
The effect is determined by the receptor not the NT.
Ways to end neurotransmitter effect
Reuptake (4): NTs are absorbed by the terminal buttons of the presynaptic neuron’s axon or by neighbouring glial cells.
Enzyme deactivation (5): specific enzymes break down specific NTs.
Diffusion (6): drift out of the synapse and can no longer reach receptors
Sequence for information travelling within a single neuron?
dendrites, cell body, axon
Effects on Neurotransmitters
Excitatory → Stimulate the target cell.
Inhibitory → Hyperpolarize the target cell (make their membrane even more negative). Decrease the likelihood of the target cell firing an action potential.
Modulatory → Influence the effect of other chemical messengers. Affect a larger number of neurons at the same time.
Glutamate and GABA (gamma-aminobutyric acid)
Glutamate: Major excitatory NT involved in information transmission throughout the brain.
GABA: Major inhibitory NT in the brain.
Acetylcholine (Ach)
Can be excitatory or inhibitory depending on the receptor.
Involved in several functions, including voluntary motor control.
Activates muscle movement.
Contributes to the regulation of attention, learning, sleeping, dreaming and memory.
Serotonin and Endorphins
Setatonin: Involved in the regulation of mood, sleep and wakefulness, eating, and aggressive
behaviour
Endorphins:
“Endogenous morphine”.
Act within the pain pathways and emotion centres of the brain.
Dopamine (DA) and Norepinephrine (noradrenaline)
Dopamine:
Involved in motor behaviour, motivation, pleasure, and emotional arousal.
Related to seeking pleasure and associating actions with rewards.
Norepinephrine:
Involved in states of vigilance or heightened awareness of dangers in the environment.
Release in the Sympathetic Nervous System associated with fight or flight response.
Drugs can mimic NT
Agonists: Drugs that increase the action of a NT.
Antagonists: Drugs that block the function of a NT
Opioids and Naloxone
Opioids:
• Pain relief and sedation → reduce transmission of pain signals
• Euphoria → block GABA from being released reducing inhibition on dopamine neurons.
• Respiratory depression!
Naloxone (Brand name “Narcan”):
• Opioid antagonist.
• Temporarily reverses the effects of opioid overdoses.
• Blocks receptor sites so opioids cannot have their effects → restores breathing.
Nervous system
Organization of NS
Nervous system: Interacting network of neurons that conveys electrochemical information throughout the body.
Two major divisions:
Central nervous system (CNS): the brain and spinal cord.
Peripheral nervous system (PNS): all parts of the
nervous system found outside the skull and spinal cord.
Central Nervous System (CNS)
Brain: Supports perception, motor functions, emotion, cognition.
Spinal cord: Branches down from the brain.
- Sensory: Receives sensory information from external world.
- Integration: Processes and coordinates this information.
- Motor: Commands skeletal and muscular systems
Regions of the Spinal Cord
4 main sections → Each controls different body parts.
Cervical Nerve, Thoracic Nerves, Lumbar Nerves and Sacral Nerves
Damage higher on the spinal cord usually means greater loss of sensation and motor control.
Peripheral nervous system (PNS):
Somatic nervous system (SNS): Conveys information into and out of the CNS.
Autonomic nervous systems (ANS): Carries involuntary and automatic commands that control blood vessels, body organs, and glands.
- Sympathetic nervous system: Prepares the body for action (fight or flight). Motor neuron (Moves)
- Parasympathetic nervous system: Helps the body return to a resting state. Sensory Neuron (Feels)
Reflexes
Spinal reflexes: Simple pathways that rapidly generate muscle contractions.
No brain involvement!
Reflex arc: Neural pathway that controls reflex actions
The Endocrine System
Hormones: Chemical messengers that influence basic functions and regulate the body’s internal environment
Pituitary (“master gland”): Regulates other glands.
Hindbrain
Brainstem (pons and medulla):
- Breathing, heart rate, swallowing
- Sorting of information going from/to the brain and the spinal cord
Cerebellum: Motor control and coordination, balance, motor learning
Midbrain
Tectum: Sensory processing, orientation to stimuli
Tegmentum: Motor processing
Forebrain
Thalamus: Sorting of information and Processing and interpretation
Hypothalamus: Regulating homeostasis
Limbic system: Emotions, learning and memory.
Amygdala: emotional processing, memory, odor perception.
Hippocampus: memory formation and spatial navigation.
Corpus callosum
Large bundle of myelinated axons
Enables communication between hemispheres
Ways to investigate the brain?
Damaged brains/lesions.
Neuroimaging techniques.
Transcranial Magnetic Stimulation (TMS)
Can (ethically) mimic brain damage.
Temporarily deactivates neurons in the cerebral cortex.
Can be combined with fMRI techniques.
Neuroimaging techniques
Different angles:
Sagittal slice (top)
Horizontal slice (bottom left)
Coronal slice (bottom right)
Gray matter: neuron bodies.
White matter: myelinated axons.
Neuroimaging techniques
Structural
Anatomy of the brain
- CT scan (Computerized axial tomography)
- MRI (Magnetic resonance imaging)
- DTI (Diffusion tensor imaging)
Neuroimaging techniques
Functional:
Brain activity while someone engages in a cognitive or motor task
- PET (positron emission tomography)
- fMRI (functional magnetic resonance imaging)
- fMRI and DTI (measures structural connectivity)
Studying the Brain’s Electrical Activity
Recording electrical activity in neurons.
- Electroencephalograph (EEG): Device used to record electrical activity in the brain
- Single neuron detection
Cortex
Four lobes (Gyrus and Sulus)
Frontal, parietal, occipital and temporal
Organization
Across Hemispheres
Left and right hemispheres
Contralateral control.
Connected by commissures;
largest of these is the corpus
callosum.
Organization
Within Hemispheres
4 lobes
Parietal: spatial cognition, touch
Frontal: Movement
Occipital: Visual
Temporal: language and hearing
Precentral gyrus: In the frontal lobe, anterior to central sulcus, primary motor cortex.
Postcentral gyrus: In the parietal lobe, posterior to central sulcus, primary
somatosensory cortex.
Corpus callosum
Insula: addiction and motivational process
Brain Plasticity
Ability of the brain to be changed by environment and experience.
Experience can affect the number and size of neurons as well as the strength of
their connections.
Occurs both during development and in adulthood.