Module 5 - Sensation, Perception And Conciousness Flashcards
Sensation
Detection of physical energy by our sensory organs, which is then relayed to the brain
5 Sensations
Seeing, hearing, touching, tasting and smelling
Perception
Putting all sensations together and interpreting inputs
Bottom-up Processing
Taking information, assembling it and integrating it
Top-down processing
Using models, ideas and expectations to interpret sensory information
Reception
Stimulation of sensory receptor cells by energy (sound, light, heat)
Transduction
Transforming cell stimulation into neural impulses
Transmission
Delivering neural information to brain to be processed
Absolute threshold
Minimum level or stimulus intensity needed to detect a stimulus half the time
Subliminal
Below our threshold for being able to consciously detect a stimulus, but still registered by the sensory organ
Difference threshold
Minimum difference for a person to be able to detect the difference
Weber’s Law
Two stimuli to be perceived as different they must differ by a constant minimum percentage and not a constant amount
Signal Ditection Theory
Whether or not we detect a stimulus particularly with background noise
What does detection depend on?
Psychological Factors; alertness, expectations, motivation and sensory experience
Gestalt
Understand laws of our ability to acquire and maintain meaningful perception in a chaotic world
Law of Pragnaz
Perceive stimuli in our environment in their simplest form
Proximity
Physically close to each other tend to be unified as wholes
Similarity
Similar to each other tend to be perceived as unified wholes
Continuity
Intersection between objects tend to be perceived as two single uninterrupted entities
Closure
Parts combined to make wholes
Symmetry
Perceive objects that are symmetrically arranged as wholes
Common faith
Perceive elements of objects to have trends of motion
Figure-ground
Centre of our attention, we ignore the background
Electromagnetic Radiation
Many types of wave but our eyes only respond to some (colour)
Wavelength
Colour or hue
Amplitude
Intensity or brightness
Long wavelength
Red
Short wavelength
Blue
Large amplitude
Bright
Small amplitude
Dull
Key Structures of the Eye
- Lens
- Pupil
- Iris
- Blind Spot
- Optic Nerve
- Fovea
Cornea
Focused and inverted
Retina
Transduction
Photoreceptors
Rods and Cones - light receivers
Photoreceptors - Step 1
Light entering eye triggers photochemical reaction in rods and cones at back of retina
Photoreceptors - Step 2
bipolar cells activated
Photoreceptors - Step 3
Bipolar cell activate ganglion cells, the axons of which converge to form optic nerve
Optic Nerve
Transmits information to the visual cortex in the brain
Ganglion Cells
Object recognition
Supercells
Recognize more complex forms of
Young-Helmholtz Trichromatic Theory
Assumes three types of colour receptor (red, green and blue)
What happens when some type of cones are missing
Colour-blindness
Opponent-process theory
Neural process based on sets of complementary colours (pairs inhibit each other)
- White - black
- Yellow - blue
- Red - green
Which Theory is Correct?
They’re both supported
Young-Helmontz Thichromatic Theory - Receptor Level
Opponent Process theory - Ganglion Cells and Visual Cortex
Monocular Cues
Require one eye to perceive depth
Linear Perspective
Lines converge to a common point at a distance
Relative Size
More distant objects look smaller
Texture GRadient
Texture becomes less apparent the further it is
Interposition
Closer objects black view from objects further away
High in Plane
Distant objects are higher and closer objects are lower
Binocular Disparity
Eye transmits different information for near objects, ut become similar the further away objects are
Binocular convergence
- When we ook at nearby objects our eyes converge together
- brain can track eye muscle movement to estimate distance
Parallel Processes
Building perceptions out of sensory details processed in different areas of the brain at the same time
Consciousness
- Perceptions
- Subjective Experiences
- Intentionality
- Self-awareness
What does attention do?
guide perception
Broadent’s filter theory of attention
Attention is a bottleneck through which information passes
Selective Attention
What we focus on is what we consciously perceive
Selective Inattention
Failure to notice part of our environment when our attention is directed elsewhere
Subliminal consciousness
Below threshold for being reliably able to consciously detect stimulus but still registered by the sensory organ
Does subliminal influence work
Yes, for a short period of time when all distractions are removed
Naive Realism
False belief that our senses are infallible and that our perceptions off representations of the world
unconscious “low” track
- Bottom up
- below the absolute threshold but still registered by sensory organ
- doesn’t require attention
- automatic actions
Conscious “high” track
- top down
- above the absolute threshold
- requires attention
- leads to deliberate actions based on what we recognize in our environment
Context effects
Provides us basis for expectations
Perceptual SEt
What we expect to see influences what we do see (top-down processing)
Perceptual Constancy
Ability to perceive objects as having constant, shape, size and colour despite changes in perspective
Automatic Variations (examples)
Daydreaming, drowsiness, sleep and dreams
Physiological Variations (examples)
Hallucinations, lack of oxygen and orgasms
Psychological Variations (examples)
Sensory deprivations, hypnosis and mindfulness meditations
Consciousness during sleep
Not a single state but multiple states that vary in frequency, amplitude and regularity (measured with EEG)
Awake and Active
- Beta Waves
- High Frequency
- Low Amplitude
Awake and Calm
- Alpha Waves
- Lower frequency then beta
- higher amplitude then beta
Stage 1 and 2
- Theta waves
- Lower frequency then alpha
- larger amplitude than alpha
Stage 3 and 4
- Slow-wave sleep
- Delta waves
- very low frequency
- high amplitude and regular
Stage 5
- REM
- Brain activity increases
- beta and alpha re-appear
- heart rate and respiration increase
- dreaming
What does REM sleep deprivation lead to
REM rebound
What happens during 90 minute cycle?
Slow wave sleep decreases and time spent in REM increases
Why do we sleep - 4 reasons
- Protection: hidden without movement
- Recover: restore and repair brain tissue
- Consolidation: build and rebuild memories
- Growth: growth hormones are released
Effects of sleep deprivation
- decreased concentration
- impaired memory
- impaired emotional regulation
- impaired immune system
improving sleep
- regular schedule
- decrease stimulation before bed
- exercise
- avoid naps
- reassure yourself
- avoid quick fixes
Psychoactive substances
Naturally or artificially created substances that alter the state of consciousness, perception, mood, and/or the regulation of behaviour
Stimulants
- Euphoria
- increased energy
- lower inhibition
- increased dopamine, serotonin and norepinephrine activity
- ex. Cocaine
Hallucinogens
- distortion of sensory and perceptual experiences
- leads to fear, panic and paranoia
- increased serotonin
- block glutamate receptors
- ex. Ketamine
Depressants
- Drowsiness, relaxation sleep
- increase GABA activity
- release of endorphines
- ex. Heroin
Physical Dependence
Physical needs of a drug that has painful withdrawal symptoms (changes in physiological processes)
Psychological Dependence
Repeated experience of positive emotions and reduction of negative emotions during the administration of a drug
Addiction
Involuntary servitude to obtain a substance, caused by physical and psychological dependence
alcohol
- stimulant, hallucinogenic and a depressant
- facilitates GABA activity
- endorphin release
- tolerance builds so dependence is high
Drinking
- accumulates in blood and body tissues to get to liver
- No safe amount
