Nature vs. Nurture Influences on Development

Nature vs. Nurture

• Nature refers to inherited genetics, including physical and psychological traits.
• Nurture refers to environmental influences and experiences shaping an individual from infancy to adulthood.
• Nature provides physical traits, while nurture shapes behavior, skills, and personality.
• The interaction of nature and nurture constantly shapes behaviors.
• Charles Darwin's theory of evolution explains how advantageous traits are passed to future generations.
• Evolutionary psychology explains the persistence of certain behaviors through history.
• Eugenics, a movement promoting selective breeding in the early 20th century, misused evolutionary psychology.
• Eugenics led to enforced sterilizations and discrimination in the US from the early 1900s to the 1930s.
• Psychological research isolates the influence of genes and environment with twin, adoption, and family studies.
• Studying identical twins helps isolate the influence of the environment on behavior.
• Adoption studies separates home environment influences from genetic factors by tracking behavior.
• Family studies help identify the influence of genetic factors on traits across generations.

The Nervous System

• The nervous system consists of the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS contains the brain and spinal cord.
• The brain processes sensory data and coordinates responses.
• The spinal cord relays neural messages to various body parts.
• The PNS includes nerve endings branching from the brain and spinal cord throughout the body.
• The PNS transmits information to and takes orders from the CNS.
• The PNS is divided into the somatic and autonomic nervous systems.
• The somatic nervous system processes voluntary movement and transmits sensory information to the CNS.
• The autonomic nervous system controls involuntary functions like heart rate, digestion, and breathing.
• The autonomic nervous system is divided into the sympathetic and parasympathetic nervous system.
• The sympathetic nervous system activates the fight or flight response during perceived threats.
• The parasympathetic nervous system returns the body to normal functioning after the threat is gone.

Neurons and Glial Cells

• Neurons are the nervous system's primary communication cells.
• Neurons are found throughout the nervous system.
• Neurons send neural messages to the right body parts.
• Glial cells support, protect, and nourish neurons; also clean up waste in the nervous system.
• The nucleus contains the neuron's genetic information.
• The cell body or Soma provides structural support and processes nutrients.
• Dendrites receive incoming messages from other neurons.
• The axon sends information to the next neuron.
• The myelin sheath (glial cells) wraps around the axon, speeding up neural messages.

Types of Neurons and Reflex Arcs

• Sensory neurons collect sensory information and send it to the brain.
• Motor neurons carry out motor actions sent from the brain and release hormones.
• Interneurons direct messages throughout the entire nervous system.
• A reflex arc demonstrates how sensory, motor, and interneurons work together to create reflexive responses.
• In a reflex arc, sensory neurons send a signal of pain to the spinal cord.
• Interneurons process the signals as a pain response and send a message to motor neurons.
• Motor neurons cause a reflexive movement away from the stimulus.

Action Potentials

• When a neuron receives stimulation, it fires off an electrical charge called an action potential.
• The neuron must receive enough stimulation to meet the stimulus threshold for an action potential to occur.
• The All or Nothing principle says a neuron either generates an action potential or does not.
• After firing, a neuron enters a refractory period to recharge and cannot send a message at this time.
• After recharging, the neuron remains at the resting potential ready to send the next message.
• When an action potential reaches the axon terminal, the neuron releases chemicals to transmit the message.
• After transmission, chemicals are reabsorbed through reuptake, allowing them to be reused; conserving the body's resources.
• Multiple sclerosis and myasthenia gravis are autoimmune disorders where white blood cells attack neurons.
• Symptoms of both disorders include muscle weakness, fatigue, and loss of mobility.

Neurotransmitters

• Neurotransmitters are chemical messengers that control aspects of life.
• Excitatory messages increase brain activity by triggering more action potentials.
• Inhibitory messages slow down brain activity by preventing further action potentials.
• Dopamine is crucial for pleasure and reward systems, influencing mood, attention, and movement.
• Dopamine pathways activate in response to humor and the expectation of hearing something inappropriate or funny.
• Serotonin helps regulate mood, appetite, and sleep; a lack of Serotonin is linked to depression symptoms.
• Nephrine affects alertness and arousal and is very similar to adrenaline.
• Glutamate is an excitatory neurotransmitter and is critical for regulating cognitive functions, such as learning and memory.
• Gaba (gamma aminobutyric acid) is a major inhibitory neurotransmitter that slows down brain activity.
• Endorphins act as natural painkillers and induce feelings of pleasure and happiness.
• Substance P regulates pain, signaling when something is wrong in the body.
• Aetyl choline stimulates muscle contractions and plays a role in attention and memory.

Neural Transmission

• The presynaptic neuron sends a message and the post synaptic neuron receives the message.
• Neurons do not touch, but form a tiny, fluid-filled gap called the synapse.
• Neurotransmitters are stored in synaptic vesicles at the end of the axon.
• When an action potential reaches synaptic vesicles, it forces neurotransmitters into the synapse.
• Receptor sites on the dendrites of the post synaptic neuron are tailored to specific neurotransmitters.
• When a matching neurotransmitter binds to a receptor, it can either inhibit or excite the neuron.
• Excitation triggers an action potential in the post synaptic neuron, while inhibition keeps it at rest.
• Once neural communication is complete, neurotransmitters are reabsorbed via reuptake.
• Reuptake occurs in synaptic vesicles.

Hormones

• Hormones of the endocrine system influence behavior and work closely with the nervous system.
• The endocrine system is controlled by the hypothalamus and the pituitary gland.
• Adrenaline prepares the body to spring into action during fight or flight by increasing heart rate, blood pressure, and energy.
• Leftin is released by fat cells, which helps with regulating energy balance by suppressing appetite.
• Grelin is released into the stomach to stimulate appetite and to encourage eating, when the body needs more energy.
• Melatonin is released by the pineal gland when it gets dark, preparing for sleep; decreasing production in the morning.
• Oxytocin helps with social bonding and reproduction and is released as a result of physical touch.

Psychoactive Drugs and Addiction

• Psychoactive drugs alter brain function, causing changes in perception, mood, consciousness, and behavior.
• Agonists mimic the effects of natural neurotransmitters.
• Antagonists stop chemicals from binding to a receptor site.
• Reuptake inhibitors block the process of re-uptake to increase the levels of a specific neurotransmitter.
• Selective serotonin reuptake inhibitors (SSRIs) block the re-uptake of Serotonin to fight depression symptoms.
• Stimulants (caffeine, cocaine) increase brain activity, causing elevated alertness, attention, and energy.
• Depressants (alcohol) slow down central nervous system activity, which can lead to decreased anxiety, inhibition, and motor skills.
• Hallucinogens alter perceptions, moods, and thoughts and also affect the nervous system.
• Marijuana is classified as a hallucinogen.
• Opioids (heroin) relieve pain and create euphoria and increase dopamine levels, which can lead to strong addiction.
• Addiction is chronic and causes drug seeking and use despite harmful consequences.
• Addiction can affect physical health, relationships, and school or work life.
• With continuous drug use, the brain adapts, requiring more of the substance to achieve the same effects (tolerance).
• Withdrawal symptoms occur after developing a dependence on a substance and then stopping use.

Brain Structures and Functions

• The brain stem contains the medulla, which controls automatic functions such as breathing, heart rate, and blood pressure.
• The cerebellum is responsible for motor control, coordinating voluntary movements such as posture, balance, and speech.
• The reticular activating system (RAS) regulates the sleep wake cycle and attention.
• The lyic system is the emotional center of the brain.
• The brain Reward Center playing a critical role in decision-making and addictive behaviors is located primarily in the lyic system.
• The thalamus acts as the brain's sensory relay station, channeling incoming sensory information to the appropriate areas of the brain.
• The hypothalamus regulates vital life functions such as hunger, thirst, temperature, and emotional responses.
• The hypothalamus controls the pituitary gland, the master gland of the endocrine system, affecting growth, metabolism, and reproduction.
• The hippocampus creates new memories.
• The amygdala processes emotional aspects of memory, including fear and pleasure responses.
• The cerebral cortex is divided by the left and right hemisphere, with the Corpus colossum connecting them.
• The occipital lobe is responsible for visual processing.
• The temporal lobe deals with auditory interpretation and sounds.
• The parietal lobe processes sensory signals, which is crucial for spatial orientation and navigation.
• The frontal lobe is responsible for decision making, problem solving, planning, controlling speech, and motor movements.
• The prefrontal cortex, at the tip of the frontal lobe, is responsible for decision-making, planning, and social behavior.
• The motor cortex is responsible for planning and the executing of voluntary movements.
• The somata sensory cortex processes sensory information from across the body, creating a sensory map.
• Broka area, located in the left hemisphere of the frontal lobe, is responsible for speech production.
• Verne's area, in the left hemisphere's temporal lobe, is essential for language comprehension.
• Aphasia is an impairment in language abilities that can occur from damage to Broka or Verne's area.
• The split brain procedure reduces epileptic seizures by cutting the Corpus colossum to make communication from the left and right hemisphere impossible.
• Cortex specialization highlights the distinct functions of cerebral cortex regions; the left hemisphere primarily manages language tasks, while the right hemisphere excels in spatial reasoning and facial recognition.
• Brain plasticity is the brain's ability to change its structure and functions as a result of injury or learning.
• Functional plasticity is the brain's ability to shift functions from a damaged area to a non-damaged area.
• Structural plasticity is the brain remarkable ability to change its physical structure through learning and experience.
• FMRI measures brain activity by detecting changes in blood flow.
• EEG measures brain electrical activity using electrodes placed on the scalp.
• Lesioning studies occur when an area of the brain is intentionally damaged in order to observe its effect on behavior.
• Case studies involve observing individuals with naturally occurring brain damage.

Consciousness and Sleep

• Consciousness is awareness of mental processes and the external environment.
• Wakefulness and sleep are the two primary levels of consciousness.
• The sleep wake cycle is controlled by the circadian rhythm, an internal biological clock.
• Modern life factors like jet lag and electronics can disrupt our circadian rhythm.
• Sleep comes in multiple stages: nonrapid eye movement (NRM) and rapid eye movement (RM).
• Stage one NRM sleep is light sleep where one can easily be awakened and where hypnogogic hallucinations can occur.
• Stage two NRM sleep is where brain activity slows further, but waking up becomes a little more difficult than stage 1
• Stage three NRM sleep is the deepest sleep; the body rejuvenates, the immune system strengthens, and memories consolidate.
• Muscle movements are suppressed during RM sleep (sleep paralysis), where brain activity is similar to wakefulness.
• RM sleep processes emotions, consolidates memories, and is essential for brain functioning.
• Restorative Theory suggests we sleep for physical repair and recovery of the body.
• Adaptive theory proposes sleep evolved to conserve energy and reduce danger.

Dreams and Sleep Deprivation

• Activation synthesis theory states that dreams result from the brain's attempt to make sense of random neural activity.
• Memory consolidation theory suggests that dreams process and consolidate memories.
• Sleep deprivation weakens the immune system, increases heart rate, impairs memory, reduces concentration, and increases irritability and mood swings.
• Insomnia involves difficulty falling or staying asleep and is often caused by stress and poor sleep habits.
• Narcolepsy is characterized by extreme daytime sleepiness and sudden episodes of falling asleep.
• RM sleep behavior disorder involves acting out dreams violently during sleep.
• Sleep apnea is caused when blocked Airways interrupt breathing during sleep.
• Somnambulism (sleepwalking) involves walking around during nrm sleep.

Sensation and Perception

• Sensation is the process of sensory organs collecting information and sending it to the brain for processing.
• Transduction occurs when physical stimuli are converted into electrical signals the brain can understand.
• Absolute threshold refers to the minimum strength that a stimulus has to have in order to be detected 50% of the time.
• The difference threshold, or just noticeable difference (j& D), the smallest change in a stimulus that is detected.
• Weber's law states that the ability to detect a change depends on the intensity of the original stimulus.
• Sensory adaptation is the brain's ability to decrease its sensitivity to constant stimuli.
• Sensory interaction is the process by which different senses influence one another to enhance perceptions.
• Synesthesia is a condition where stimulation of one sensory pathway leads to experiences of a secondary sensory pathway.
• Sensory receptors are specialized cells within all of the senses that transduce sensory information to the brain.

Vision

• Light waves reach the eyes, accommodation focuses vision, and directs light to the retina.
• Fovea allows for Sharp detailed vision.
• Signals are converted and sent through the visual nerve to the brain for visual processing.
• Rods are the sensory receptor cells being highly sensitive to light, which helps us see at night.
• Cones respond to color vision.
• Bipolar cells then filter data before sending it to the gangan cells, the visual nerve.
• The tri chromatic theory states that we have three types of cones sensitive to red, green, or blue light.
• The opponent process theory proposes that color perception involves neurons and processes colors in opposing pairs (blue/yellow; red/green; black/white).
• Nearsightedness (myopia) occurs when the eye is too long and causes blurry vision for far away objects.
• Farsightedness (hyperopia) occurs when the eye is too short and causes blurry vision when looking at objects up close.
• Color blindness is the inability to perceive some or all colors.
• Di chromatism involves trouble distinguishing between two colors, such as red and green.
• Monochromatism causes the inability to perceive any color at all.
• Prosopagnosia (face blindness) is a neurological disorder impairing the ability to recognize faces.
• Blind sight is a condition where individuals can respond to visual stimuli without conscious of perceiving.

Hearing

• Sound waves strike the eardrum, and vibrations are transferred to the auditory ossicles in the middle ear.
• Inside the cochlea, sensory receptors known as hair cells move in response to vibration.
• Soundwave vibrations are converted into neural messages.
• Pitch identifies how high or low a sound is and depends on the frequency of Soundwave vibrations.
• Amplitude determines sound loudness and also relates to the intensity of a sound wave.
• Sound localization determines where a sound is coming from by differences in arrival at each ear.
• The frequency Theory states that nerve impulses traveling up the auditory nerve matches the frequency of a tone.
• The Volley Theory suggest that groups of auditory neurons take turns firing in Rapid sequence.
• The place theory argues the location where the membrane vibrates the most allows humans to distinguish the pitch of the sound.
• Conductive hearing loss occurs from a blockage in the outer or middle ear, which prevents sound from reaching the inner ear.
• Sensory neural hearing loss results from damage to the inner ear or auditory nerve.
• Mixed hearing loss is when you combine sensory neural and conductive hearing loss together.

Smell and Taste

• The senses of smell and taste are the chemical senses.
• The sense of smell (olfaction) begins when odor molecules bind to receptor cells located on the olfactory epithelium.
• Receptor cells transform smell to the olfactory bulb, which is relayed to the olfactory cortex.
• The sense of tastes' receptor cells are taste buds, and is also known as gustation.
• When we eat something, the chemicals in the food are broken down by saliva and then they get in contact with the taste buds.
• Taste buds create a neural message for the taste and sends it to the brain.
• Taste buds can detect sweet, sour, salty, bitter, and Umami.
• Researchers identified a new taste called oleogustus (the taste of dietary fats).
• People are categorized as a super taster, medium tasters, or non-tasters.
• Taste is reliant on smell for humans to experience its full flavor.

Touch and Pain

• Mechanico receptors detect touch and pressure.
• Thermo receptors gauge temperature, which allows humans to distinguish between warm and cold.
• No acceptors alert humans to potential pain or harm signals coming to the body.
• In gate control theory, pain signals travel through a gate in the spinal cord that can open and close to regulate humans perception of pain.
• Phantom limb sensation is when individuals continue to feel pain or Sensations in a limb that has been amputated.

Kinesthetic and Vestibular Senses

• The kinesthetic sense detects body position, weight, and movement, helping track position and movement.
• Propri receptors located through muscles and Joints track body movements and alert the brain.
• Neural messages that reach the somata sensory cortex gives a clear sense of body position and motion.
• The vestibular sense provides information about balance and spatial organization.
• Hair cells are located in the semi circular canals of the ear.
• Hair cells react to changes in head movements to maintain and coordinate balance through nerve impulses.