Perception and consciousness COPY Flashcards
Perceptual organization:
Although a visual scene may contain a copious amount of information about many different features (e.g., color, shape, motion, contours, etc.) and these features are processed separately by distinct neural systems, we perceive (“see”) unified objects in the scene because our brains recombine these elements, binding them together.
• How these features are organized into objects is governed by gestalt principles and influenced by bottom-up and top-down processing.
Gestalt principles:
- Gestalt principles: This body of research emphasizes the point that how we organize the barrage of incoming sensory information is a central feature of perception.
- Visual information—i.e., a barrage of information about various visual features—tends to be organized (or “parsed”) according to the following principles:
Similarity: Similar-looking figures tend to be grouped together, e.g., by color and orientation.
Proximity: Figures that are closer together in space tend to be grouped together.
Continuity of subjective contours: We tend to group figures together to perceive contours (edges) that may not physically exist in a visual scene.
For example, all three of these principles are at work when we perceive a zebra standing behind a tree. Its hind legs and tail are visible on one side of the tree, and its front legs and head are visible on the other. Yet we recognize and perceive a single zebra because of the similarity and proximity of the two separate parts and because of our innate preference for continuity of contours.
Closure: We tend to fill in missing parts or gaps to create a whole.
Similarity:
Similarity: Similar-looking figures tend to be grouped together, e.g., by color and orientation.
Proximity:
Proximity: Figures that are closer together in space tend to be grouped together.
Continuity of subjective contours:
Continuity of subjective contours: We tend to group figures together to perceive contours (edges) that may not physically exist in a visual scene.
For example, all three of these principles are at work when we perceive a zebra standing behind a tree. Its hind legs and tail are visible on one side of the tree, and its front legs and head are visible on the other. Yet we recognize and perceive a single zebra because of the similarity and proximity of the two separate parts and because of our innate preference for continuity of contours.
Closure:
Closure: We tend to fill in missing parts or gaps to create a whole.
Closure: objects grouped together are seen as a whole. Mind fills in missing information. Ex. You fill in the triangle even though there is none.
Depth Perception
Monocular cues: need information from only one eye.
Interposition: one object in front of another; cues depth perception.
Motion parallax: When we are moving, we tend to perceive objects that are closer to us as moving faster.
Binocular cues: need information from both eyes.
part of depth perception 2
interposition and motion parallax
Interposition: one object in front of another; cues depth perception.
- added: Perception that one object is in front of another. An object that is in the front is closer.
- *Monocular cues can also give a sense of motion**
- Motion parallax- “relative motion” Things farther away move slower, closer moves faster.
Motion parallax: When we are moving, we tend to perceive objects that are closer to us as moving faster.
MONOCULAR CLUES*
Types of processing:
Types of processing: What we perceive is a product of two simultaneous processing streams.
Bottom-up processing is driven by sensory inputs; e.g., when reading a list of words, we recognize the shape of the letters that make up the words, and upon recognizing the letters C, A, and T, we perceive the word “cat” and imagine a furry animal with four legs and a tail.
Top-down processing is driven by our own internally generated ideas and expectations; e.g., when reading the same list of words, we might recognize words for animals slightly faster than other words if we have just spent some time in a pet store.
Bottom-up processing
Bottom-up processing is driven by sensory inputs; e.g., when reading a list of words, we recognize the shape of the letters that make up the words, and upon recognizing the letters C, A, and T, we perceive the word “cat” and imagine a furry animal with four legs and a tail.
Bottom up Processing: Begins with stimulus. Stimulus influences what we perceive (our perception).
o No preconceived cognitive constructs of the stimulus (never seen it before)
o Data driven. And the stimulus directs cognitive awareness of what you’re looking at (object)
o Inductive Reasoning. Always correct.
Top-down processing is
Top-down processing is driven by our own internally generated ideas and expectations; e.g., when reading the same list of words, we might recognize words for animals slightly faster than other words if we have just spent some time in a pet store.
Top-down Processing: uses background knowledge influences perception. Ex. Where’s waldo
o Theory driven. Perception influenced by our expectation
o Deductive Reasoning
o ex. creating a cube when it’s not there! Not always correct.
consciousness
Our constantly updated awareness of ourselves, our environments, and the relationship between the two; may enable executive control—the capacity to override well-learned habits and actively redirect our attention, thoughts, and actions to accomplish a goal.
Sleep 1
A state of consciousness characterized by low alertness.
In deep sleep, there is an absence of consciousness.
In dreaming sleep, consciousness is present (but altered) and alertness remains low.
In deep sleep…..
In deep sleep, there is an absence of consciousness
In dreaming sleep……..
In dreaming sleep, consciousness is present (but altered) and alertness remains low.
stages of sleep 1
Stages of sleep: can be characterized by measuring muscle tone and brain activity rhythms through an EEG (electroencephalogram).
Non-REM Stage 1: falling asleep; a mix of alpha (8–13 Hz) and theta (4–7 Hz) waves on EEG; normal muscle tone.
NREM Stage 2: light sleep, still easily awoken by stimulation; mostly theta waves on EEG with sleep spindles and K-complexes.
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
Non-REM Stage 1:
Non-REM Stage 1: falling asleep; a mix of alpha (8–13 Hz) and theta (4–7 Hz) waves on EEG; normal muscle tone.
high frequency, same frequency we are when awake
NREM Stage 2:
NREM Stage 2: light sleep, still easily awoken by stimulation; mostly theta waves on EEG with sleep spindles and K-complexes.
brain slowing down
NREM Stage 3:
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
MOST RESTORATIVE, most refreshing sleep, very active dreaming
there is something abotu rem sleep that we need, mystery what it is doing for our brain we do not actually know
Rapid eye-movement (REM) sleep
alpha (8–13 Hz) waves on EEG, similar to wakefulness, but difficult to arouse and absent muscle tone.
-REM initiated by acetylcholine, inhibited by serotonin.
- Dreaming tends to occur during REM sleep.
- Bouts of REM sleep occur every 90 minutes and last longer later in the night.
- If deprived of REM one night, will compensate with more REM the following night.
alpha waves highest frequency, associated with REM, brain waves get slower
and slower then get fast again high frquency again as go through rem sleep
then go through another cycle of nonrem where get slower and slower
Circadian rhythms
Circadian rhythms: Sleep and wakefulness occur in cycles that are linked to the circadian rhythm/time of day.
The urge to sleep is driven by two processes:
- The time of day: the urge to sleep increases gradually from a nadir during the late morning and then rapidly at night.
- The duration of wakefulness: the urge to sleep increases with the time spent awake.
These two processes interact and can interfere with our desire for sleep:
Night shift workers may have difficulty sleeping during the day.
Napping in the early evening may cause difficulty falling asleep at your normal time at night.
Sleep cycles also vary with age:
16 hours per day in infancy in two-hour bouts; 50% REM sleep.
9 hours per day in adolescence in one bout; 20% REM sleep.
6 hours per day in old age in one bout that begins and ends earlier in the day (10:00 p.m.–4:00 a.m. in old age vs. 1:00 a.m.–10:00 a.m. in adolescence).
Narcolepsy
(kind of sleep disorder 1)
sleep intrudes involuntarily on wakefulness at undesired times during the day.
• In extreme cases, can be associated with complete loss of muscle tone and triggered by excitement.
this is people faling asleep when they do not want to
Insomnia:
Insomnia: an inability to fall asleep or maintain sleep despite feelings of fatigue.
• A category of sleep disorders that can be caused by medical illness, drugs, and medications, or problems intrinsic to the brain’s sleep machinery.
sleep disorders can also be called= dyssomnias= abnormalities in the amount, quality or timing of sleep i.e either insomnia, narcolepsy and sleep apnea
or sleep wake disorders= abnomalities again in amount, quality and time of sleep
Circadian rhythm sleep disorders:
=a category of sleep disorders caused by a mismatch between the patient’s internal circadian clock and the external time of day.
Jet lag: symptoms of insomnia and fatigue occurring after rapid travel across many time zones.
Shift work-related sleep disorder: triggered by need to sleep during the day due to working at night.
Can also be triggered by problems intrinsic to the circadian clock.
again like narcolepsy, fall asleep when you do not want to for shift work related sleep disorder
hypnosis
its quesitonable claims
An altered state of consciousness characterized by relaxation, low arousal, and in susceptible individuals, high suggestibility.
Has no effect on some people.
Questionable claims:
Hypnotic age regression: Patients may act like they are three years old but they have not “returned” to the age of three in any substantive way.
Memory retrieval: There is no evidence to support the hypothesis that patients can retrieve memories when hypnotized but not when awake; however, they are highly suggestible and vulnerable to forming false “memories” unintentionally planted by the hypnotist.
Hypnosis cnt.
What are the verified effects?
Verified effects:
Posthypnotic instructions: In some patients, hypnotic suggestions can help people change their behavior in
desirable ways, e.g., eating less or feeling less anxious on a plane.
Posthypnotic amnesia: In some patients, later access to memories of the experience of being hypnotized can be blocked and unblocked using hypnotic suggestions.
Hypnotic analgesia: In some patients, pain sensitivity can be reduced while hypnotized, e.g., tolerating dental procedures without anesthetic.
meditation
A state of consciousness similar to hypnosis in which an individual is relaxed, unresponsive to most external stimuli, and highly alert to internally generated ideas.
Unlike hypnosis, meditative states are self-generated.
Alertness
The state of being awake and also paying close attention in order to quickly perceive changes in the environment and act accordingly.
Alertness implies being awake but not vice versa (e.g., awake and drowsy vs. awake and alert).
Drug type:
Depressants
Examples:
Alcohol, Sedatives (Valium), Hypnotics (Ambien)
Brain effects:
Generally suppress neuronal activity; increase GABA signaling
Behavior effects:
Decreased arousal; disinhibition; slowed reaction time; OD: coma, death
Stimulants
Cocaine, Amphetamines (Ritalin, Adderall, meth), MDMA (ecstasy)
Brain effects:
Generally increase neuronal activity; increase dopamine and norepinephrine signaling
Behavior effects:
Increased arousal, attention, concentration; euphoria; OD: anxiety, paranoia, seizures
Hallucinogens
Ex. LSD, Psilocybin (mushrooms), PCP (angel dust), Mescaline (peyote)
Brain effects:
Often modulate serotonin transmission
Behavior effects:
Alter perceptual processes; trigger hallucinations; OD: anxiety, paranoia, psychosis; low risk of dependence
Cannabinoids
Marijuana, Hashish, Medical THC
Brain effects:
Activates cannabinoid receptors
Behavior effects:
Affects mood regulation, appetite, pain perception; OD: anxiety, dangerous when mixed with alcohol
Drug addiction
Addiction is characterized by drug-seeking behavior despite adverse consequences, usually with evidence of drug dependence.
Physiological drug dependence: Brain adapts to exposure to a drug.
Tolerance: Increasingly larger doses are required to achieve the same effect.
Withdrawal: Physical symptoms that occur when a patient is no longer intoxicated.
Psychological drug dependence: Although there may be no physical withdrawal symptoms, psychological dependence can occur when a patient experiences psychological symptoms when no longer intoxicated (e.g., depression, anxiety, low energy, lack of motivation).
The reward pathway***
Rewarding experiences trigger dopamine release from neurons in the ventral tegmental area (VTA) and into the nucleus accumbens, a region of the ventral striatum.
Drugs of abuse activate the reward pathway and long-term abuse leads to lasting changes in reward processing that may predispose to addiction.
Q. 10 Rem sleep is characterized by:
high brain activity and LOW** muscle tone
sleep apnea
intermitten cessation of breathing during sleep, which results in repeated awakenings
parasomnias
- doing weird things, this is about BEHAVIORS, abnormal behaviors that occur during sleep
- ex. sleep walking called somambulism or night terrors
- somambulism= tends to occur during slow wave sleep (stage 3), usually happens during the first third of the nights
- many children experience sleep walkign adn eventually grow out of it
- night terrors= appearing terrified, babbling screaming while deep asleep
- usualy also occura during stage 2 unlike nightmares, which occur durign REM** sleep towards the morning*
- screamign and terrified –> parents can go soothe them and cannot wake them up, they are terrified, again usually grow out of night terrors
RAS
Reticular Activating system
aprt of rbain which cotnrols levels of alertness and consciousness
alertness and arousal is controlled by the RAS in the brain
alpha brain wave
7 Hz to 14 Hz
assocaited with relaxaed, normal conscoousness
Awake but not necessarily highly alert, kind of just chilling but awake
do not know if need to know but beta waves=
state of higher alert, need to focus more intently on something and can see frequency of brain waves inc go from alpha to beta** 15 Hz to 30 Hz
theta brain waves
4 Hz to 7 Hz
seen in young children, mediatiative states and stage 1 sleep*
adults do not often exhibit theta brain waves, if actually good at meditating, highly relaxed or drifting off to sleep that is WHEN we show these waves
not across a normal day*
delta brain waves
less than 4 Hz
occurs during slow wave sleep
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
SCN
Suprachiasmatic nucleus in the hypothalamus
regulates sleep, melatonin production by the pineal gland and body temperature
the daily pattern of cortisol production by the adrenal cortex is influenced by several interacting systems, only one of which is the master clock in the SCN***
sleep stages
what is the most important?
what is the most important= sleep stages 3 and 4
most restorative sleep, this is where our blood pressure drops, breathign slows and muscle is relaxed
where tissue growth and repair is and energy stored, very important to get to this stage if never get that deep restortive sleep with sleep apnea you have an issue
REM stage rapid eye movement when we dream abotu 25% of the night we are dreaming, first rem stage occurs abotu 90 minutes after and occurs later on*
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
REM 2
bursts of quick eye movement
about 25% of night when dreams occur, occurs about 90 min after falling alseep then every 90 minutes after gets longer later on
in the beginning not expereincign REM and then as we progress through the night it will occur about every 90 minutes. but each stretch will get longer and longer, dreaming is very important for psych repai, get physica repair in stages 3 adn 4 btu psych repair comes from dreaming
so when cut sleep short it will be problematic for us, body doesnt have time to repeat all phases needed for repair and memory consolidation**
2 monocular cues:
new 6.11
Humans also have visual cues they receive which they do not need two eyes for. Theseare monocular cues.
o These give humans a sense of form of an object
- Relative size= Can infer with one eye. The closer an object it is perceived as being bigger. Gives us an idea of form.
- Interposition (overlap)
- Motion parallax
- Relative height- things higher are perceived to be farther away than those that are lower.
- Shading and contour- using light and shadows to perceive form depth/contours – crater/mountain.
- Monocular cue of constancy
Monocular cue of constancy
Constancy – Our perception of object doesn’t change even if the image cast on the retina is different. Different types of constancy include size constancy, shape constancy, color constancy.
Size Constancy: One that appears larger because its closer, we still think it is the same size.
Shape Constancy: a changing shape still maintains the same shape perception. ex. door opening means the shape is changing, but we still believe the door a rectangle
Color Constancy: despite chagnes in lighting which chang the image color falling on our retina, we understand /perceive that the object is the same color
binocular cues: convergence
Humans have two eyes which allow them to receive visual cues from their environment by binocular cues. These give them a sense of depth.
o This gives them retinal disparity. Eyes are ~2.5 inches apart which allows humans to get slightly different views of objects of world around. Gives humans an idea on depth.
Convergence: Gives humans an idea of depth as well based on how much eyeballs are turned. Gives humans a sense of depth.
Things far away – muscles of eyes relaxed.
Things close to us – muscles of eyes contract.
Pragnanz
a gestalt principle
Pragnanz: reality organized reduced to simplest form possible. Ex. Olympic rings, where the brain automatically organizes these into 5 circles, instead of more complex shapes.
gestalt principles 2 new 6.11
Symmetry
Symmetry: the mind perceives objects as being symmetrical and forming around a center point.
3 gestalt princples added 2 6.11
Law of Common Fate: For example, if there are an array of dots and half the dots are moving upward while the other half are moving downward, we would perceive the upward moving dots and the downward moving dots as two distinct units.
Law of Past Experiences: The law of past experience implies that under some circumstances visual stimuli are categorized according to past experience. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together. For example, the English language contains 26 letters that are grouped to form words using a set of rules. If an individual reads an English word they have never seen, they use the law of past experience to interpret the letters “L” and “I” as two letters beside each other, rather than using the law of closure to combine the letters and interpret the object as an uppercase U
Contextual Effects: the context in which stimuli are presented and the processes of perceptual organization contribute to how people perceive those stimuli (and also that the context can establish the way in which stimuli are organized)
