AP Psychology unit 1

the Nature vs. Nurture Debate

The ongoing inquiry into the relative contributions of genetic inheritance versus environmental experiences in shaping human behaviour

Natural Selection 

Guides evolutionary psychology 

Behaviour Genetics

• Genes vs environment 

• Ancestral history of genes = ingrained ideas/instincts 

• Humans have a very small percentage of DNA that is unique to each individual

Environment 

Environmental factors make a gene “turn on”

the Twin Studies 

• Used to see how environmental factors impact a person 

• Raised in two different houses without knowledge of each other 

  • Families are in different socio-economic situations and housing conditions 

Epigenetics 

• The study of how behaviours and environmental factors cause reversible or lasting changes that affect how your genes work, without altering the underlying DNA sequence

Central Nervous System (CNS) 

• Decision maker 

• Spinal cord

Peripheral Nervous System (PNS)

• Sensory/motor neurons 

• Nerves + ganglia 

Somatic Nervous System

skeletal nervous system also part of PNS

Sympathetic

fight or flight part of somatic nervous system

parasympathetic

calms body down after arousal-producing event occurs part of somatic nervous system

autonomic

automatic functions such as the heartbeat or breathing part of the peripheral nervous system

neurons

• Structure: cell body, dendrites, axon, and myelin sheath

• Damaged myelin sheath = slower reaction time

• Glial cells: feed neurons, create the myelin sheath, and clean the environment

• 3 Types of Neurons

3 types of neurons

sensory neurons, motor neurons, interneurons

sensory neurons

carry incoming information

motor neurons

Carry outgoing information from the brain/spinal cord to muscles/glands

interneurons

neurons within the brain/ spinal cord

Action potential

neural impulse, travelling down the axon

Threshold:

level of stimulation needed to trigger a neural impulse

Refractory Potential

resting pause

chemical communication order

synapse, neurotransmitters, reuptake

synapse

the junction between two neurons where neurotransmitters are released to communicate.

neurotransmitters

chemical messengers that transmit signals between neurons across a synapse.

reuptake

the process by which neurotransmitters are absorbed back into the presynaptic neuron after signaling.

nerve nerve communication

Chemical messengers released into the synapse pre-action potential 

• Endorphins: released by the pituitary gland

• Acetylcholine (ACh): influences memory/muscle action

• Dopamine: like cocaine, short pathway 

• Serotonin: like LSD, longer pathway

Agonists:

substances that enhance the effect of neurotransmitters by mimicking their action at receptor sites.

Antagonists

substances that block the action of neurotransmitters by occupying their receptor sites without activating them.

Endocrine System

• Body’s ‘slow’ chemical communication

• Hormones → bloodstream (via glands/fat tissue) 

pituitary gland

• Two glands

• Next to hypothalamus

• Sets things in motion

• pretty much is hormones

types of psychoactive drugs

depressants, stimulants, hallucinogens

depressants

• Reduce neural activity 

• Barbiturates: drugs that suppress CNS activity - tranquillisers 

  • Lowers anxiety

• Opioids: decrease neural activity

  • Lowers pain levels 

• Alcohol - lowers memory/judgement

stimulants

• Increases neural activity

• Speeds up body functions 

• MDMA (ecstasy) - higher energy levels, emotion, and social disconnection

• Triggers higher release of endorphins

hallucinogens

• Altered state of consciousness

• Used for PTSD

Sensitisation

A process by which repeated exposure to a stimulus results in a heightened response to that stimulus over time. Unlike habituation, where the response decreases, sensitisation increases sensitivity to the stimulus.

Hindbrain

survival and basic functions includes: the medulla, pons, and the cerebellum

midbrain

arousal and processing takes care of reticular formation

Forebrain

is the limib system which controls emotions, memories, and complex thinking processes. It includes structures such as the thalamus. hypothalamus, hippocampus, and amygdala.

connections and hemispheres

• Corpus Callosum: large bundle of nerve fibers that connects the left and right hemispheres of the brain, facilitating communication between them.  

• Lateralisation - The specialisation of the left hemisphere (logic, language) versus the right hemisphere (spatial reasoning, face recognition)

Frontal Lobe 

• Controls voluntary movement, higher thinking, emotions, and language (personality) 

• Injury = Personality change, lower emotional control, decline in problem-solving

Parietal Lobe

• Processes sensory input and language comprehension

• Injury = lower processing of touch, spatial awareness, and coordination 

Temporal Lobe

• Processes auditory information and long-term memory

• Injury = lower memory, language difficulty, and lower auditory processing

Occipital Lobe

• Visual processing, spatial mapping, recognition

• Injury = lower fields of vision, blindness, inability to recognise objects

Auditory Cortex

• Processes sounds (pitch, speech, and music)

• Injury = decline of pitch recognition, sound localisation, and sound comprehension

Motor Cortex

• Controls voluntary muscle movements

• Injury = decline in ability to control voluntary movements/coordination

Somatosensory

• Processes sensations (touch, pain, temperature, and body position)

• Injury = disruption of senses, numbness/tingling

Broca’s Area 

• Controls speech production

• Injury = difficulty with speech (aphasia)

Wernicke’s Area 

• Comprehension of written and spoken language

• Injury = nonsensical speech, although fluent

Cerebellum

• Balance, posture, motor learning, and coordination

• Injury = unsteady/clumsy, decline of fast movements

Corpus Callosum

• Neural bridge to left and right hemispheres 

• Injury = stops the sides from communicating, lower motor and sensory abilities

Medulla

• Controls involuntary actions (breathing and heart rate)

• Injury = stops breathing and heartbeat → death

Reticular Formation

• Consciousness

• Injury = altered state of consciousness (coma)

Pons

• Relay station/connector to cerebrum, cerebellum, and spinal cord

• Injury = disrupts communication, motor deficits, and balance issues 

Thalamus

• Sensory relay and motor modulation

• Injury = sensory disturbances, chronic pain, motor issues, sleep changes 

Hypothalamus

• Regulates homeostasis (hunger, thirst, temp, etc)

• Injury = disturbs hormones, temperature, appetite, sleep, etc

Pituitary Gland

• Controls growth, metabolism, and other hormones

• Injury = fatigue, weight change, and hormonal imbalances

Cerebellum

• Balance, posture, motor learning, and coordination

• Injury = unsteady/clumsy, decline of fast movements 

Amygdala

• Processes emotion, emotional memory, and threat detection (fear)

• Injury = loss of ability to feel fear, mood swings, impairs ability to read social cues 

Hippocampus

• Long-term memory, helps you remember facts, works with the amygdala 

• Injury = disrupts ability to form new memories

Consciousness 

• Our subjective awareness of ourselves and our environment

• Helps us: 

  • Make sense of our sensations, emotions, and choices

  • “Run on autopilot” after repetitive motions 

Cognitive Neuroscience 

A field that studies the relationship between cognitive processes and brain function, integrating knowledge from psychology and neuroscience.

Dual Processing

converts conscious into unconscious knowledge

parallel processing

 brain's ability to handle multiple streams of incoming sensory and cognitive information at the same time, rather than processing things one after another (routine tasks)

sequential processing

the brain's ability to handle, organise, and execute information in a strict, step-by-step order, one piece or stage at a time (solving new problems)

Circadian Rhythm

• Internal biological clock

• Thinking and memory increase at the peak of the circadian rhythm 

• Age/experience alters the cycle 

• ~90 min cycle through the stages of sleep 

REM Sleep

(Rapid eye movement sleep)

NREM Sleep

Non-rapid eye movement sleep

Alpha Waves

Slow brain waves of a relaxed, AWAKE state

Delta waves

Dominate deep, non-REM (NREM) slow-wave sleep

stages of sleep

• Stage 1 

  • Hypnagogic Sensations - hallucinations such as falling 

• Stage 2 

  • (~20 mins) burst of rapid rhythmic brain wave activity (memory processing) 

• Stage 3 

  • (~30 min) deep sleep, brain emits delta waves 

• Stage 2 

  • Return to stage 2 after stage 3 (½ of sleep is spent here) 

• REM Sleep 

  • (~10 mins) Basically paralysed, 20-25% of time asleep is spent here 

sleep loss

• Sleep debt accumulates (brain remembers sleep debt for the past 2 weeks) 

  • Can’t be fixed with “one big sleep” 

• REM sleep processes emotional experiences and helps protect against depression

• Lack of sleep: 

  • Weight gain

  • Messes with hormones and metabolism

  • Increased errors in visual tasks 

  • Suppresses immune system

sleep disorders

• Insomnia 

• Narcolepsy 

• Sleep apnea 

• Sleep walking 

• REM sleep behaviour disorder 

dreams

• REM dreams are vivid, emotional, and bizarre

• 8/10 dreams are marked with a negative emotion or event 

• Things that happen while we sleep influence dreams 

  • Ex. spraying water in someone's face = they dream of waterfalls 

• Dreams help us understand conflicts and file memories

• Sleep develops/preserves neural pathways 

• REM rebound 

REM rebound

Sleeping undisturbed after repeated awakenings prevents us from going fully into REM sleep

Sensation vs Perception

• Sensation - the physical process where your sensory receptors detect and transduce raw environmental stimuli

• Perception - the psychological and active process by which your brain organises, interprets, and assigns meaning to those raw signals

Bottom-Up Processing

Information processing that begins with sensory receptors and works to the brain

Top-Down Processing

Cognitive and perceptual method where your brain uses prior knowledge, expectations, memories, and context to interpret incoming sensory information

Transduction

Converts outside energy into a form our brain can use

Absolute threshold

Edge of our awareness of faint stimuli

Subliminal

Stimuli you can’t consciously detect 50% of the time

Difference threshold

Minimum stimulus difference a person can detect half of the time

Weber’s Law

Two stimuli must differ by a constant minimum per cent to perceive a difference  

Sensory Adaptation

• When constantly exposed to an unchanging stimulus, we become less aware of it

• Allows us to focus on informative changes in our environment

Vision 

• Eyes receive light energy and transform it into neural messages 

• When we see red, it’s pulses of electromagnetic energy that we PERCEIVE as red 

• Wavelengths 

  • Wavelength determines the hue

  • Amplitude determines intensity 

How eyes work

• Light enters the cornea and bends light to focus 

• The light passes through the pupil, the iris dilates to help with intensity 

• Light then hits the lens to focus the light into an image on the retina

• The lens changes its curvature/thickness in a process called accommodation

Optic nerve

information highway from the eye to the brain 

Blind spot

no photoreceptor cells in part of the eye

Hearing (audition) waves

• Long waves = low frequency and low pitch 

• Intensity is measured in decibels

• Zero decibels is the absolute threshold for hearing 

middle ear bones

malleus, incus, and stapes 

cochlea

A spiral-shaped, fluid-filled structure in the inner ear that converts sound vibrations into neural signals, playing a key role in the process of hearing.

• Hair cells trigger impulses to nerve cells, which converge to form the auditory nerve

• Messages are passed through the thalamus and to the auditory cortex

Sensorineural hearing loss 

caused by damage to hair cells

Conduction hearing loss

caused by problems in the outer or middle ear that prevent sound waves from reaching the inner ear. so it is a problem with the mechanical systems of the ear

Touch

• Different spots react differently to pressure, temperature, and pain

• Cognition influences our brain’s response 

• Pain

pain

• Tells your body that something is wrong 

• Enhances self-awareness and empathy 

• Pain varies among people and based on culture/social situation

• Nociceptors detect harmful temperatures, pressures, or chemicals  

• Genes influence pain

• Phantom limb sensations 

• We don’t remember the duration of pain, just the peak and the low

• Placebos and distractions  help with pain

Taste (Gustation)

• Helps us eat the right foods

  • Toxic foods don’t taste good to us

• Tongue has 200+ taste buds

  • Catches chemicals, releases neurotransmitters

Smell  (Olfaction)

• Chemical sense 

• Only sense that bypasses the thalamus 

• Odours trigger combos of receptors

• Odours evoke emotions and are associated with memories 

Proprioceptors

• Sensory receptors that detect body position and movement

• Help maintain balance and coordination

• Located in muscles, tendons, and joints

Kinesthesis

awareness of your body parts (movement sense)

Vestibular Sens

e: The sense that contributes to balance, spatial orientation, and coordination by detecting motion and position of the head through structures in the inner ear.

McGurk effect:

• if we hear one thing but see a different movement of the mouth, our brain switches what we hear

  • Ex. in-class ‘ba’ vs ‘fa’ experiment