AP Psychology Unit 1 Flashcards
Nature vs. Nurture
The age-old question of whether nature (heredity) or nurture (environmental factors) has the most impact on human behavior is outdated.
It's now understood that both nature and nurture play a role.
Heredity vs. Environment
Heredity (Nature): The passing on of physical and mental traits from one generation to another.
Environment (Nurture): Environmental factors such as family life, social groups, education, and societal influences.
Psychological Perspectives
Different psychological perspectives lean towards either nature or nurture.
Evolutionary Approach:
Based on Darwin's theory of evolution.
Charles Darwin's theory:
Evolution happens by natural selection.
Beneficial traits for a species survive and are passed on.
Undesirable traits die off.
Eugenics
Some individuals have misused evolutionary principles to support eugenics.
Eugenics: The belief in improving the genetic quality of the human population by selectively breeding for desirable traits and discouraging reproduction among those with undesirable traits.
Epigenetics
Studies the relationship between heredity and environment and their impact on shaping behaviors and mental processes.
Focuses on how the environment and a person's behavior affect their genes and how they work.
Explains how an individual's body reads a DNA sequence.
DNA itself is not changing; epigenetics happen slowly.
Different genes are turned on or off due to sustained environmental pressures.
Epigenetics can explain why identical twins develop different physical and mental characteristics.
Twin Studies
Minnesota study of twins reared apart: Examines similarities and differences in identical twins separated at birth and raised in different environments.
Family and Adoption Studies
Researchers conduct family and adoption studies to understand the impact of heredity and environment.
COL Adoption Project: A longitudinal study that follows biological and adoptive families to gain insight into the influences of genetics and the environment on cognitive abilities, personalities, and mental processes.
Plasticity
Different from epigenetics, which affects gene expression, plasticity is the brain's ability to change and adapt as a result of experiences.
Involves strengthening or weakening neural connections.
Allows the brain to be flexible and adapt to changing experiences.
The Nervous System
Central Nervous System (CNS) vs. Peripheral Nervous System (PNS)
CNS: Brain and spinal cord. Sends out orders to the body.
PNS: Nerves that branch off from the brain and spine. Connects the CNS to all the body's organs and muscles.
Afferent vs. Efferent Neurons
Afferent Neurons (Sensory Neurons): Send signals from sensory receptors to the CNS.
Efferent Neurons (Motor Neurons): Send signals from the CNS to the PNS.
Mnemonic: Afferent Approaches; Efferent Exits the brain.
Somatic vs. Autonomic Nervous System
Somatic Nervous System (Skeletal Nervous System):
Includes the five senses and skeletal muscle movements.
Movements happen consciously and voluntarily.
Autonomic Nervous System:
Controls involuntary activities.
Ensures heart keeps beating, stomach keeps digesting, and breathing continues.
Sympathetic vs. Parasympathetic Division
Sympathetic System:
Mobilizes the body and gets it ready for action.
Increases heart rate, dilates eyes, and increases breathing.
Fight or flight response.
Parasympathetic System:
Relaxes the body.
Slows heart rate, increases digestion, and helps focus on saving and storing energy.
Rest and digest response.
Mnemonic: Parachute - Slows you down.
Glial Cells
Provide structure, insulation, communication, and waste transportation.
Most abundant cells in the nervous system.
Support neurons through protection and provide them with nutrients.
Do not process information or send messages.
Neurons
Basic functional unit of the nervous system.
Communicate using electrical impulses and chemical signals to send information throughout the nervous system.
Three types of neurons create a reflex arc: sensory, motor, and interneurons.
Reflex Arc
Nerve pathway that allows the body to respond to a stimulus without thinking.
Involves sensory neurons, motor neurons, and interneurons.
Example: Touching something hot:
Skin receptors detect heat and send a signal through a sensory neuron to the spinal cord.
The signal goes to interneurons within the brain and spinal cord.
Interneurons communicate internally and connect sensory neurons to motor neurons within the CNS.
The signal goes to motor neurons, and then back to the muscles in the hand and arm to move, causing the hand to pull away from the hot surface.
All happens through the body's autonomic response.
The reflex arc helps protect us by allowing the body to respond to a threat before processing what is occurring.
Neural Transmission
Neurons need to receive enough stimulation to cause an action potential.
Action Potential: When a neuron fires and sends an impulse down the axon.
Cell membrane separates ions and creates a positive or negative environment on either side of the barrier.
Permeability: Some ions can cross the membrane more easily than others.
Resting Potential: When a neuron is not sending a signal, it has more negative ions on the inside than the outside.
Depolarization
A neuron must depolarize to trigger an action potential, happening when an outside stimulus is strong enough to meet the threshold, and the neuron fires an action potential.
If the stimulus does not meet the threshold, there is no firing, and the neuron returns to its resting state.
All-or-nothing principle: The neuron will only fire if the threshold is met.
When an action potential occurs, it sends a signal down the axon to other neurons in the nervous system.
Repolarization
The process that brings the neuron back to resting potential.
Channels open to rebalance the charges by letting more positive ions back outside the cell membrane.
Refractory Period
During repolarization, the neuron cannot respond to any other stimulus.
The cell cannot fire and needs to wait until repolarization occurs and the cell goes back to resting potential.
Synapse
Once a signal makes its way down the axon of a neuron, it is sent down to the axon terminal.
The signal is converted and sent to another neuron through a small pocket of space between the axon terminal of one neuron and the dendrite of another neuron.
Tiny space is known as the synapse.
Types of synapses: chemical and electrical.
Chemical synapses use neurotransmitters.
Electrical synapses send messages quickly and immediately.
Neurotransmitters
Chemical messengers that send messages through the nervous system.
Diffuse through the synaptic gap to deliver messages.
Synaptic Gap: A narrow space between two neurons, specifically the presynaptic terminal of one neuron and the postsynaptic terminal of another neuron.
Presynaptic Terminal: The axon terminal of the neuron, which converts the electrical signal to a chemical one and sends the neurotransmitters into the synaptic gap.
Postsynaptic Terminal: Where the neurotransmitters are accepted in the dendrite of the receiving neuron.
Reuptake
Once neurotransmitters have been sent, they unbind with the receptors, and some are destroyed, while others are reabsorbed.
Reuptake: Taking excess neurotransmitters left in the synaptic gap. The sending neuron reabsorbs the extra neurotransmitters.
Excitatory vs. Inhibitory Neurotransmitters
Excitatory Neurotransmitters: Increase the likelihood that a neuron will fire an action potential through the depolarization process in the postsynaptic neuron.
Inhibitory Neurotransmitters: Decrease the likelihood that a neuron will fire an action potential, which leads to hyperpolarization, where the inside of the neuron becomes more negative, moving the neuron farther away from its threshold.
Neural Transmission Events (in order)
Action potential sends a signal down the axon of the neuron to the presynaptic terminal.
Channels in the axon terminal are opened, and neurotransmitters are released into the synaptic gap.
Neurotransmitters diffuse through the synaptic gap and bind to receptor sites in the postsynaptic terminal.
Neurotransmitters unbind with the receptors, and some are destroyed, while others go through the process of reuptake.
Neurological Disorders
Disruptions in neural transmission can lead to neurological disorders such as:
Multiple Sclerosis: Damage to the myelin sheath disrupts the transmission of electrical signals, leading to symptoms like muscle weakness, coordination problems, and fatigue.
Myasthenia Gravis: Autoimmune disorder that affects the communication between nerves and muscles. Antibodies block or destroy acetylcholine receptors, preventing muscle contraction and causing muscle weakness and fatigue.
Types of Neurotransmitters and Their Functions
Acetylcholine: Enables muscle action, learning, and helps with memory.
Substance P: Helps with transmitting pain signals from the sensory nerves to the CNS.
Dopamine: Helps with movement, learning, attention, and emotions.
Serotonin: Impacts hunger, sleep, arousal, and mood.
Endorphins: Help with pain control and impact an individual's pain tolerance.
Epinephrine: Helps with the body's response to high emotional situations and helps form memories.
Norepinephrine: Increases blood pressure, heartbeat, and alertness. Part of the body's fight or flight response.
Glutamate: Involved with long-term memory and learning.
GABA: Helps with sleep, movement, and slows down your nervous system.
Hormones and the Endocrine System
Hormones
Hormones perform different functions similar to neurotransmitters.
Adrenaline (Epinephrine): Helps with the body's response to high emotional situations. Expands air passages in the lungs, redistributes blood to muscles, and is involved in the body's fight or flight response.
Leptin: Helps regulate energy balance by inhibiting hunger. Signals to the brain that the body has enough stored fat, reducing a person's appetite.
Ghrelin: Signals to the brain that we are hungry and also helps promote the release of growth hormones.
Melatonin: Produced by the pineal gland in the brain. Helps regulate the sleep-wake cycles, also known as circadian rhythms. Released and helps promote sleep and is typically more prevalent in the evening in response to darkness.
Oxytocin: Produced in the hypothalamus and released by the pituitary gland. Promotes feelings of affection and emotional bonding.
Endocrine System
The endocrine system is slower moving than the nervous system.
Sends hormones throughout the body's blood to target larger areas of the body, all to help regulate different biological processes.
The nervous system uses neurons to quickly send messages to localized areas of the body.
Psychoactive Drugs
Agonist vs. Antagonist Drugs
Agonist Drugs: Increase the effectiveness of a neurotransmitter.
Antagonist Drugs: Decrease the effectiveness of a neurotransmitter.
Agonists bind to the receptors in the synapse that are for neurotransmitters. These substances increase the effectiveness of the neurotransmitters by mimicking them, increasing the production of the neurotransmitter, or blocking reuptake, which makes them more available in the synapse.
Antagonist drugs work in multiple ways. They either block the neurotransmitters from being released from the presynaptic axon terminal, or they connect to the postsynaptic receptors and block the intended neurotransmitters from binding.
Examples of Agonist and Antagonist Substances
Agonist Substances:
Anti-anxiety medications such as Xanax: Increase the neurotransmitter known as GABA, which decreases neural activity and can calm people down.
Prozac: Used to treat depression. Delays the reuptake of the neurotransmitter serotonin, making it more available for the body to use.
Opioids
Antagonist Substances:
Medication for schizophrenia: Blocks dopamine receptors.
Alcohol: Blocks the release of glutamate, which acts as a depressant for our nervous system.
Categories of Psychoactive Drugs
Stimulants: Excite and promote neural activity. Give an individual energy, reduce a person's appetite, and can cause them to become irritable. Examples: caffeine, nicotine, or cocaine.
Depressants: Reduce neural activity in an individual. Cause drowsiness, muscle relaxation, lowered breathing, and if abused, possibly death. Examples: alcohol or sleeping pills.
Hallucinogens: Cause an individual to sense things that are not actually there. They can also reduce an individual's motivation and can lead an individual to panic. Examples: marijuana, peyote, or LSD.
Opioids: Function as a depressant. Give an individual pain relief. Examples: morphine, heroin, or oxycodone.
Tolerance, Addiction, and Withdrawal
Using different psychoactive drugs can lead a person to develop a higher tolerance.
Tolerance: Requires more of the drug to be consumed to achieve the same effect. This could result in addiction and withdrawal symptoms.
Brain Structures
Major Regions of the Brain
Hindbrain: Located at the bottom of the brain.
Midbrain: Located in the center, sitting above the base of the brain.
Forebrain: The top of the brain, and what most people visualize about the brain when thinking about it.
Structures of the Hindbrain
Spinal Cord:
Connects your brain to the rest of your body.
Allows nerves to send information to the brain and vice versa.
Brain Stem:
Located at the base of your brain on top of the spinal cord.
Includes the medulla, the pons, and the midbrain.
If severely damaged, it will most likely result in death because it controls autonomic functions.
Medulla Oblongata:
Right above the spinal cord and below the pons.
Helps with the regulation of a person's cardiovascular and respiratory systems.
Takes care of autonomic functions.
Pons:
The bridge between different areas of the nervous system.
Connects the medulla with the cerebellum and helps with coordinating movement.
Also helps with sleep and dreams.
Reticular Activating System:
Part of the reticular formation.
A network of nerve cell bodies and fibers within the brain stem.
Involved in the regulation of arousal, alertness, and sleep-wake cycles.
Helps stimulate other brain structures when something important happens and needs our immediate attention.
Cerebellum:
Located in the back of the brain, just below the occipital lobes and behind the pons.
Helps with coordinating voluntary movements, maintaining posture and balance, refining motor skills, and plays a role in cognitive functions.
Sometimes referenced as the little brain.
The Midbrain
Helps with processing visual and auditory information, motor control, and integrating sensory and motor pathways.
Structures of the Forebrain
When picturing the brain, most people are thinking of the cerebrum, which is the largest part of the brain. This is what deals with complex thoughts.
The cerebrum is divided into two hemispheres, the left and the right, and each hemisphere can be further subdivided into four different lobes.
Made up of gray matter called the cerebral cortex and white matter.
Cerebral Cortex: A thin outer layer of billions of nerve cells that cover the whole brain.
Corpus Callosum: Located beneath the cerebral cortex, consists in a thick band of nerve fibers that connects the two cerebral hemispheres and allows them to communicate with each other.
Lobes of the Brain
Frontal Lobe:
Located just behind your forehead.
Deals with higher-level thinking.
Prefrontal Cortex: Deals with foresight, judgment, speech, and complex thought.
Motor Cortex: Deals with voluntary movement and is located in the back of the frontal lobe. The left motor cortex controls movement on the right side of your body, and the right motor cortex controls movement on the left side of your body.
Exhibits contralateral hemispheric organization: the brain's hemispheres control opposite sides of the body and process sensory information.
The functions of the motor cortex can be visualized through the motor homunculus, which shows a visual representation of the amount of brain area that is dedicated towards a specific body part.
Broca's Area:
Found only in the left hemisphere in front of the motor cortex.
Crucial for language production, particularly in controlling the movements of the muscles involved in speech.
First identified by Paul Broca.
Broca's Aphasia: If Broca's area is damaged, the loss of the ability to produce language occurs. Individuals with Broca's aphasia can still understand language and speech but struggle to speak fluently.
Parietal Lobe:
Located in the upper part of the brain, right behind the frontal lobe.
Main function is to receive sensory information. Lets you understand things such as touch, pain, temperature, and spatial orientation. The different senses help with processing and organizing information.
Somatosensory Cortex:
Situated parallel to and directly behind the motor cortex.
Responsible for processing touch, pressure, temperature, and body position
The left sensory cortex controls sensations for the right side of your body, and the right sensory cortex controls sensations for the left side of your body.
The amount of brain area that is dedicated towards specific body parts can be visualized when looking at the sensory homunculus.
Temporal Lobe:
Located right above your ears.
Involved in processing auditory and linguistic information, recognizing faces, and assists with memory.
Hippocampus: Helps us learn and form memories, but is not where memories are stored.
Amygdala: Emotional reactions come from the amygdala. Used for fear, anxiety, and aggression.
Auditory Cortex: Located in the superior temporal gyrus of the temporal lobe. This is what processes the different sounds that you hear and allows you to recognize things like music and speech.
Wernicke's Area:
Typically located in the left temporal lobe.
Responsible for creating meaningful speech.
If this part of the brain is damaged, a person will lose the ability to create meaningful speech. This is known as Wernicke's aphasia.
Occipital Lobe:
Located at the back of the brain, just above the cerebellum.
Responsible for processing visual information.
Contains the primary visual cortex, which is what receives visual input from the eyes.
Not only processes basic information but more complex visual tasks as well, such as recognizing objects, understanding spatial relationships, and perceiving depth and movement.
Vision does not confine to just one area of the brain. For instance, the occipital lobe may detect an object's color and shape; the temporal lobe helps with identifying the object, and the parietal lobe helps understand the spatial orientation.
Thalamus:
Located deep within the brain, just above the brain stem.
Receives sensory information from your sensory organs for everything except for the sense of smell.
Relays information to the appropriate areas of the cerebral cortex for processing. People often call the thalamus a relay station.
For instance, visual information from the eye is sent to the thalamus, which is then relayed to the occipital lobe for visual processing.
Limbic System:
Located on both sides of the thalamus.
Made up of different brain structures whose main function is emotions, learning, memory, and some of our basic drives.
Hypothalamus:
Helps keep your body balanced and allows you to have homeostasis.
Controls drives, such as thirst, hunger, temperature, and sex.
Works with the pituitary gland to regulate and control your hormones.
Pituitary Gland:
Often referenced as the master gland.
Produces and releases hormones that regulate many bodily functions and control other endocrine glands throughout the body.
Brain Lateralization
The differing functions of the left and right hemispheres.
It is the division of labor between the two hemispheres. Each hemisphere has different areas that it is more efficient in.
The brain does have hemispheric specialization.
The left hemisphere is better at recognizing words, letters, and interpreting language, while the right hemisphere is better at spatial concepts, facial recognition, and discerning direction.
Brain Examination
Phineas Gage
A railroad worker who was injured when a tamping rod shot clean through his head.
Lived and walked away from the accident without any cognitive defects.
Had a severe personality change because the rod had severed his limbic system.
His accident allowed researchers to better understand different brain structures.
Split-Brain Patients
Patients who go through a procedure that cuts the corpus callosum, which connects the left and right hemispheres of the brain.
Done to help treat people with severe epilepsy.
When the corpus callosum is cut, the right and left hemispheres can no longer communicate.
Patients who had the split-brain procedure done do not see any impact or change with their personality or intelligence.
Allow researchers to test for cortex specialization, which allows them to understand how different areas of the cerebral cortex are specialized for specific functions.
For instance, researchers found that when patients were shown a word in their right visual field, the patient was able to say the word without any problem. But when the words were shown to the left visual field, the patient would say they did not see anything. However, even though the individuals said they saw nothing, they could draw the word with their left hand. Once they drew the word, then they could identify it because now their right visual field would see the picture they drew. This is because the left hemisphere contains language.
Lesion Studies and Autopsies
Lesion Studies: When doctors and researchers will destroy specific parts of the brain to gain insight into different functions of the brain. This can be done to try and treat specific disorders.
Autopsies: An examination of an individual's body who has died to discover the cause of death. Allows individuals to better understand the extent of a disease, help determine the exact cause of death, and can also help provide important information for an individual's next of kin.
Neuroplasticity
The human brain has the ability to change, modify itself, and even repair itself.
Whenever we are learning new skills, information, and growing, this can lead to neuroplasticity to occur.
We can also run into different situations which can lead to brain damage, such as infections, neurotoxins, genetic factors, head injuries, tumors, or even a stroke, just to name a few. Depending on the severity of the damage, the brain may or may not be able to recover, which can have life-altering impacts on an individual.
When we learn new information or even when we practice old skills, the brain creates neural pathways, and the more you practice a skill, the more you study information, the more developed the pathways become.
Neuroimaging Techniques
EEG (Electroencephalogram): Uses electrodes that are placed on the individual's scalp. This allows researchers to record electrical signals from neurons firing, which can help with sleep and seizure research.
fMRI (functional Magnetic Resonance Imaging): Similar to an MRI but shows metabolic functions. This can help with better understanding brain activity. This shows a much more detailed picture compared to other scans like a PET scan.
Sleep and Consciousness
Consciousness
Our awareness of ourselves and our environment.
Types of consciouness: wakefulness and sleep.
Wakefulness: When we are awake. During this state, we are typically aware of our surroundings and can think, feel, and react to events.
Sleep: Involves a lower level of awareness. During this state, we are not fully aware of our surroundings, but our brains are still active and can process some information like sounds or sensations.
Cognitive Neuroscience
Studies how brain activity is linked with cognition.
Circadian Rhythm
Your biological clock is about a 24-hour cycle and involves changing your blood pressure, internal temperature, hormones, and regulating your sleep-wake cycle.
Impacts when we feel alert and awake and feel sleepy and ready for bed.
Adjusts overtime with our age and different life experiences.
Disruptions to the Circadian Rhythm
If you start working the night shift and are up all night, or if you travel across time zones, your internal clock will almost become out of sync with the local time.
Jet Lag: Causes an individual to feel tired, disoriented, and sluggish.
Brain Waves
Using an EEG, we can visualize different brain waves to help us understand which stage we are in.
An EEG allows us to measure the frequencies of a wave, which is the number of waves per second, and the amplitude, which is the size of the wave.
Types of waves:
Alpha Waves: Slower waves that have a high amplitude.
Beta Waves: Low in amplitude and are the fastest brain waves. Generally occur when we're engaged in mental activities.
Theta Waves: Have a greater amplitude compared to beta waves and alpha waves and even a slower frequency. These area strong during times of relaxation.
Delta Waves: Have the greatest amplitude and the slowest frequency. Occur when you are most relaxed, often times during the deepest levels of sleep.
Stages of Sleep
Non-REM Stage One: A very light sleep that only lasts about 5 to 10 minutes. The body will start to relax, and your mind starts to slow. The most common waves are alpha waves during this stage.
Non-REM Stage Two: A transitional stage that lasts normally around 10 to 20 minutes. Here, an individual will experience K-complexes and sleep spindles, which are bursts of neural activity. The most common waves are theta waves during this stage.
Non-REM Stage Three: One of the deepest states of sleep and normally lasts around 30 minutes. Growth hormones are produced during this stage, and an individual may experience sleepwalking or sleep talking. The most common waves during this stage are delta waves.
REM (Rapid Eye Movement): The last stage. External muscles are paralyzed while your internal muscles and structures become active. The brain emits beta waves during this stage. Generally lasts about 10 minutes. The individual may experience dreams or nightmares. REM sleep is considered paradoxical sleep since the brain waves during this stage are similar to wakefulness, but the body is at its most relaxed. As the sleep cycle progresses, the periods of REM sleep become longer and more frequent.
REM Deprivation and Rebound
Being deprived of REM sleep may cause a person to experience REM rebound.
REM Rebound: The next time the deprived person sleeps, they will enter REM sleep more quickly and also spend more time in REM to make up for the lost sleep.
Hypnagogic Sensations
Occur during non-REM stage one.
When an individual experiences sensations that you imagine are real. These sensations happen when you are in a light sleep. For example, if you feel like you are falling in a dream, you may wake up quickly thinking that you're falling in real life.
Theories About the Purpose of Dreams
Activation Synthesis Theory: Dreams are the brain's way of making sense of random neural activity during sleep. When we enter REM sleep, we experience activity in our brain, and the brain tries to make sense of this activity by creating a story or dream.
Consolidation Theory: Dreams help process and strengthen our memories and experiences while we sleep, especially during REM sleep. The brain organizes and strengthens the connections between neurons related to recent experiences and information. Dreams are merely a reflection of the brain's effort to process and integrate new information.
Restoration Theory: We sleep because we get tired from daily activities, and we sleep to restore our energy and resources.
Reasons for Sleep
Sleep is crucial for the body's physical and mental restoration.
Sleep is a way that we can protect ourselves as individuals.
Different animals sleep for different lengths of time and at different times of day, depending on when they are active and when other threats may be out.
Sleep helps in memory consolidation; it allows the body to strengthen the neural pathways, allowing for better recall in the future.
Sleep also supports growth and conserves energy. When we sleep, we are able to conserve our energy and save it for when we need it during the day. When we sleep, the pituitary gland releases growth hormones, which help with muscle development.
Sleep and dreams can help an individual become more creative.
Sleep Disorders
Insomnia: A sleeping disorder where an individual will have trouble falling asleep or staying asleep. This can be caused due to stress, pain, medication, or an irregular sleep schedule.
Sleep Apnea: When an individual has a hard time falling asleep or staying asleep because they are struggling with their breathing. This prevents an individual from being able to get a good night's sleep and go into REM since they keep waking up due to their breathing problems.
REM Sleep Behavior Disorder (RBD): A condition where a person acts out their dreams during REM sleep. Normally, the body is paralyzed during REM sleep, but in RBD, this paralysis is absent or possibly incomplete. Individuals with RBD may be at risk for self-injury since they may leave their bed and could get hurt when acting out their dreams.
Somnambulism: More commonly known as sleepwalking. A disorder where a person gets up and walks around while still sleeping. This most commonly occurs during stage three sleep when an individual is in deep sleep. It's more common in children but can also occur in adults.
Sleep Terrors (Night Terrors): When an individual will experience intense fear while sleeping, which can cause an individual to experience sleep deprivation and a disrupted sleep schedule.
Narcolepsy: These individuals will struggle to sleep at night and will uncontrollably fall asleep during the day.
Sensation
Sensation vs. Perception
Sensation: The process of detecting information from the environment.
Perception: Is covered in Unit Two.
Whenever you are taking an outside stimulus through one of your senses, you activate your sensory neurons, which end up creating a sensation for you.
Sensory Transduction: The process of a sensation being activated by sensory neurons.
Absolute Threshold
The smallest amount of stimulation needed for you to notice a sensation at least 50% of the time.
Sensory Adaptation vs. Habituation
Sensory Adaptation: Happens when we have a stimulus that is continuous and doesn't change. For example, if you light a candle in a room, at first you can smell it, but as the day goes on, eventually you can no longer smell the candle. But if someone else comes into the room, they will smell it right away.
Habituation: When you are repeatedly exposed to a stimulus and start to have a reduced response to the stimulus. For instance, the first time a person does drugs, they might get a strong reaction from the drug, but if they continue to use the drug, they will need to take more and more of the drug to feel the same effect.
Difference Threshold
The minimum change between two stimuli that is needed to cause an individual to detect the change. For instance, if you turn the sound up in your car or on your computer, can you tell the difference between each of the different volumes? At what point can you no longer tell the difference?
Weber's Law: The idea that for us to notice a difference between two stimuli, the two stimuli must differ by a constant percent, not a constant amount.
Sensory Interaction
When our sight, hearing, taste, touch, and smell work together.
Our senses don't operate in isolation; they constantly influence each other to help us understand and respond to the world around us.
Synesthesia
A neurological condition where one sense experiences through another. For example, a person with synesthesia might see colors when they hear music or taste flavors when they read words in a book.
The Visual Sensory System and the Eye
Whenever light enters the eye through the cornea, it passes through the pupil, where the lens focuses the light onto the retina at the back of the eye.
Retina: Made up of layers of light-sensitive cells known as photoreceptors. These convert the light into neural impulses that allow for the brain to process what the eye is seeing.
When the retina captures light and visual information, transduction occurs.
The cells convert the light into electrical signals, which are sent to the brain for processing.
The neural impulses travel through the optic nerve from the eye, briefly stop at the thalamus, then travel to the primary visual cortex, where the information will be processed in the occipital lobe.
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