Unit 1 AP Psych

Behaviour Genetics

the scientific study of how genes and the environment influence individual differences in behavior.

Natural Selection (eugenics)

inherited traits that enable an organism to survive and reproduce in an environment will be passed on to succeeding generation

Mutation

random error in gene replication that leads to a change

heredity

nature

genetic transfer of characteristics from parent to offspring

environment

nurture

every non-genetic influence (prenatal pills to the people and things around us.)

monozygotic twins

a single fertilized egg splits into two, creating two genetically identical organisms

dizygotic twins

separate fertilized eggs share a maternal prenatal environment, but are basically like siblings.

epigenetics

study of environmental influences on gene expression that occur without a DNA change

What is the nervous system?

the body’s speedy, electrochemical communication network consisting of nerve cells of the peripheral (PNS) and central (CNS)

Made up of neurons that communicate using neurotransmitters (NT). neurons release NT

nerves

• sensory neurons

• motor neurons

• interneurons

bundles of axons that link the CNS to muscles, glands, and sense organs.

• bring sensory info to the CNS

• send the info from CNS to the body

• connect neurons within the CNS

CNS

brain and spinal cord

• coordinate incoming sensory messages and outgoing motor messages

brain’s neurons get into groups called neural networks

spinal cord controls reflex in the reflex arc

reflex arc

Touching something hot:

1. Skin senses heat → sends signal through a sensory neuron to the spinal cord.

2. Interneuron in spinal cord passes the message to a motor neuron.

3. Motor neuron tells muscles to pull your hand away.

4. It’s a reflex—your brain reacts (feels pain) after your body moves.

peripheral nervous system (PNS)

made up of sensory and motor neurons

All the nerves outside the brain and spinal cord. It connects the CNS to the rest of the body.

somatic nervous system

part of PNS

voluntary skeletal muscle control

autonomic nervous system

part of PNS

involuntary control of glands and muscles (heart, lungs, etc.)

sympathetic (symp)

part of ANS

arouses the body, mobilizing its energy

fight, flight, or freeze

dilating pupils, fast heartbeat, digestions stops, bladder holds, adrenal glands stimulate release of neurotransmitters

maintains body’s homeostasis

parasympathetic

part of ANS

calms the body, conserving its energy

rest/digest

pupils contract, heartbeat slows, digestion stimulated, bladder goes

maintains body’s homeostasis

neurons

a nerve cells that is the basic building block of the nervous system (queen bees)

resting potential (1.3a)

the resting state of the neuron

the charge is positive outside, and negative inside

excitatory signals

inhibitory signals

action potential

Excitatory signals = like pressing the gas pedal — they tell the neuron to go (send a message).
Inhibitory signals = like pressing the brake — they tell the neuron to stop.

If excitatory signals outnumber inhibitory ones enough to reach the threshold, the neuron fires an action potential (sends an electrical message down the axon).

all-or-none response

fire or u dont

like a lightswitch

depolarization

The inside of a neuron is more negative than the outside. When Na⁺ (sodium) ions enter, it makes the inside less negative, causing depolarization — a small loss of the normal charge difference.

repolarization

Repolarization happens after depolarization. K⁺ (potassium) ions flow out of the neuron, making the inside more negative again and bringing it back to its resting state.

refractory period

neurons need short breaks.

during a resting pause (refractory period), subsequent action potentials cant occur until the axon returns to its resting state.

the neurons fire again after it rests

How do neurons communicate with each other

sending neuron releases neurotransmitters across a synapse to the receiving neuron

synapse

the junction between the axon tip of the sending neuron and the dendrite or soma of receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gap, received by neurons

reuptake

unused NT taken back up to the the sending neuron

endorphines

“Morphine-within”

group of natural, opiate-like neurotransmitters.

linked to pain control and pleasure!

agonists

A chemical or drug that mimics a neurotransmitter and activates its receptor, increasing its effect

antagonists

inhibiting neuron firing

stops/blocks neurotransmitter’s actions

endocrine system

slow chemical communication system. set of glands and fat tissue that secrete hormones into bloodstream. regulate bodily functions, growth and development

hormones

chemical messengers manufactured by the endocrine glands. travels thru bloodstream.

adrenal gland

when the sympathetic nervous system activates, adrenal glands release epinephrine (adrenaline) and norepinephrine (noradrenaline) to energize the body.

pituitary gland

endocrine system’s most influential gland.

hypothalamus (part of the CNS and endocrine system) direct the pituitary gland to regulate growth and control other endocrine glands.

psychoactive drugs (1.5B)

alter perceptions and mood.

depressants

downers that calm neural activity and slow body functions

stimulants

uppers that temporarily excite neural activity and arouse body functions

hallucinogens

distort perceptions and evoke sensory images in the absence of sensory input

“mind-manifesting” drugs

tolerance/withdrawal

tolerance: user requires more doses to experience the drug’s effect because the user’s brain experiences neuro-adaptation.

withdrawal: stopping the drug will make it hard for user

addiction

lack of control/social functioning/too much usage

want the drug more than like the drug

substance use disorder

continued substance craving and use despite significant life disruption/physical risk.

alcohol

depressant type

slows brain’s activity (judgment, inhibitions, memory, processing of experience, less self-awareness and less sexual inhibitions)

opioids

opium and its derivatives (morphine and heroin) depress neural functioning. lessens pain for temporary period of relief but makes effects worse

too much use of this will cause brain to stop producing endorphines, which can even cause death

what are considered stimulants

nicotine, caffeine, cocaine

speeds up body functions. helps to stay awake, lose weight or boost mood/performance. but ofc, there’s addiction and withdrawal issues.

nicotine

stimulating and highly addictive psychoactive drug found in tobacco

signals the CNS to release neurotransmitters.

cocaine

powerful and addictive stimulant. produces temporary increased alertness and euphoria, depleting brain’s supply of neurotransmitters dopamine, serotonin, and norepinphrine

marijuana (cannabis) and THC

amplifies sensitivity to colors, sounds, tastes and smells.

form of mild hallucinogen. causes delusions and anxiety

marijuana relaxes and produces euphoric high.

sleep (1.5)

a periodic of natural loss of consciousness

circadian rhythm

It's your body's natural 24-hour clock that helps control when you feel awake or sleepy, and it also affects things like body temperature, hormones, and digestion. It helps your body sync with day and night.

jetlag

This causes symptoms (daytime fatigue, lack of alertness, poor coordination, increased risk of diabetes/cancer) that result from crossing multiple timezones at highspeed.

alpha waves

in bed with eyes closed, relaxed but awake state

NREM-1 and Hypnogogic Sensations

During this brief NREM-1 sleep you may experience fantastic images resembling hallucinations.

You may have a sensation of falling or floating weightlessly.  Sometimes a leg or arm may jerk.

These hypnagogic sensations may later be incorporated into your memories.

NREM-2 stage

there are periodic sleep spindles, bursts of rapid, rhythmic brain-wave activity.

you could be awoken without too much difficulty, but asleep.

NREM-3

lasts for 30 minutes.

brain emits large, slow delta waves and it’s hard to wake up

REM stage sleep

a reoccurring sleep stage where vivid dreams commonly occur

aka paradoxical sleep; muscles are relaxed but other body systems are active

motor cortex is active, but brainstem blocks its message. if ur awake during this time, there will be sleeping paralysis.

heart rate rises, irregular breathing, eyes dart around rapidly

REM rebound

tendency for REM sleep to increase following REM sleep deprivation

information-processing theory

dreams help sift, sort and consolidate the day’s experiences in our memory

brain scans have confirmed the link between rem sleep and memory

activation synthesis theory

Your brain gets random activity while you sleep, and it tries to turn that into a story—that’s your dream

Freud’s Wish-Fulfillment Dream Theory

Freud believed that dreams help people express hidden desires, especially ones that might be unacceptable in real life.

He divided dreams into two parts:

• Manifest Content – What happens in the dream (the storyline).

• Latent Content – The hidden meaning behind the dream.

Freud also thought that many adult dreams, even if they don’t seem sexual, are connected to deep, hidden desires.

dopamine

reward and movement

oversupply: schizophrenia

undersupply: parkinson’s

serotonin

moods and emotion

undersupply: depression

norepinephrine/noradrenaline

hormone and neurotransmitter

sympathetic (fight/flight) nervous system arousal

glutamate

excitatory signal in nervous system

gaba

major inhibitory signal in nervous system

endorphines

pain control, happiness

acetylcholine (ACh)

memory, muscle action

under supply: Alzheimer’s

blocked receptors: Myasthenia gravis

Substance P

pain signals

cell body (soma)

glial cells: support/nourish/protect neurons (worker bees)

contains nucleus. produces genetic info

dendrites

receives incoming messages. conducts impulses towards cell body

axon

attached to soma, passes msgs away from cellbody to other neurons,muscles,glands. action potential travels down this

myelin sheath

fatty tissue encasing the axons of neurons. speeds up signal down axon, provides insulation to prevent impulse interfereing

terminal branches

store neurotransmitters. allows communication across synapse (junction where neurons communicate)

adrenaline

fight or flight

leptin

suppress hunger

Ghrelin

Stimulate hunger

Melatonin

causes sleep

Oxytocin

Love and bonding

Higher level consciousness

Controlled processes- totally aware

Lower-level consciousness

Automatic processing (day dreaming, phone numbers)

Altered states

Produced through drugs, fatigue, hypnosis

Circadian rhythm

24-hour biological clock

Body temps and awareness change due to this

Controlled by superchiasmatic nucleus in the brain

beta waves

Awake

Stage 1 nrem

Light sleep

Consolidation theory

Help us sort out the days events and consolidate our memories

Activation synthesis theory

Rem triggers neural activity that evokes random visual memories, which our sleeping brain turns into stories

Insomnia

Inability to fall asleep

Narcolepsy

Fall asleep out of nowhere due to orexin defeciency

Rem sleep behaviour disorder

Acting out the content of dreams while asleep

Somnambulism

Sleep walking due to fatigue, drugs, and alcohol

Sleep apnea

Stop breathing suddenly while asleep (associated with obesity)

what is sensation

How we detect physical energy from the environment and encode it as neural signals

Absolute threshold

Detection of signal 50% of the time

faint sound in a small room

Difference threshold / Just noticeable difference (JND)

Minimum difference between two stimuli required for detection 50% of the time

noticing when the volume goes up or down

Webber’s law

• Small originals → small change is noticeable.

• Large originals → need a bigger change to notice.

Signal detection theory

We don't just sense things automatically—we detect them based on our attention, motivation, and expectations.

Sensory adaptation

Diminished sensitivity as a result of constant stimulation (you can’t feel ur underwear)

Frequency (wavelength)

What colour (hue)?

Amplitude (wave height)

How bright?

Pathway of vision

“Lazy Cats Play Like Real Runners By Going Over Open Oceans.”

Light → cornea → pupil/iris → lens → retina → rods/cones → bipolar cells → ganglion cells → optic nerve → optic chiasm → occipital lobe

“Lazy Cats Play Like Real Runners By Going Over Open Oceans.”