Sensation and Perception Flashcards
A-Delta Fibres
- Thick, myelinated axons that are used in the fast pathway for pain perception.
- These axons are responsible for sharp, instant pain, such as that when you first scrape your knee
Absolute Threshold
The smallest strength needed to detect a stimuli 50% of the time
Accommodation
Curvature of the lens adjusts to change your focus
ie. the lens changes to make it easier to focus on near or far objects
Additive Colour Mixing
Adding wavelengths of light to a mixture to produce colour
ie. Shining 3 different coloured spotlights onto a blank background
Afterimage
The image that persists after there is no more stimuli
ie. looking at a bright light and then seeing the splotchy after effects on the wall
Auditory Localization
The act of locating a sound in space
Basilar Membrane
- Found in the inner ear
- Houses hair-like structures (cochlea) that are sensitive to vibrations in the inner ear fluid
Binocular Depth Cues
- Clues about depth that are perceived with both eyes
- Uses retinal disparity and convergence
Blind Spot
An area in your visual field you cannot detect due to a hole in the retina called the “Optic Disk”
Bottom-Up Processing
- Interpreting visual stimuli beginning with lines, making them into shapes and then into meaningful objects
- This may be the type of processing used when looking at impossible figures, which is why they seem fine at first glance but become baffling later on
C Fibres
- Thin, unmyelinated axons used in the slow pathway in the regulation of pain
- Responsible for long-lasting pain such as aches and burns
Cochlea
Hair-like structures in the inner ear that send auditory stimuli to the brain
Colour Blindness
- Inability to differentiate certain colours
- More common in males
- Most colour blind people are dichromats
Comparitors
People, objects, events or other standards used to make judgments or comparisons
Complementary Colours
- Colours that when mixed together, form grey
- They are found at opposite ends of the colour wheel from each other
ie. yellow and purple
Complex Cells
Respond to stimulus in any position in their receptive fields
Cones
- Specialized visual receptors that are important in daylight vision and colour vision
- Provide better sharpness and precise detail
- Found in the centre of the eye
Convergence
- Cue in binocular depth
- Senses the eyes turning toward each other as they look at objects, hinting at their distance away
Cornea
Transparent window at the front of the eye where light travels through
Dark Adaption
The process of the eye becoming more sensitive to light to accommodate for the dark conditions
Depth Perception
The ability to sense where objects are using binocular and monocular clues
Dichromats
- Attributed to colour blindness
- Having only 2 colour channels and being insensitive to either red, green or blue
Distal Stimuli
Distant / external visual stimuli that your eye does not “touch”
Door-in-the-Face Technique
A manipulation tactic that works by making an offer that is likely to be refused in order to increase the chances of a more reasonable offer (that was wanted in the first place) being accepted.
Farsightedness
- Distant objects appear clear, but objects close appear blurry
- May come from the eye being too short
Feature Analysis
Detecting elements in visual stimuli and creating something meaningful out of them
ie. lines becoming a rectangle which becomes your phone
Feature Detectors
Specialized neurons that react to specific features of complex visual stimuli
Fechner’s Law
States that the intensity of a sensory experience is determined by the number of JNDs the stimulus is above the absolute threshold
Fovea
Tiny spot in the centre of the retina that is densely packed with cones, making it the best for sharp vision
Frequency Theory
States that the perception of pitch is determined by the frequency of which the entire basilar membrane vibrates
Gate-Control Theory
- States that pain signals must go through a gate at the spinal cord which can be closed, inhibiting pain signals to get to the brain
- Created by Ronald Melzack and Patrick Wall
Gustatory System
- Sense of taste
- Gustatory receptors are clusters of cells in our taste buds that absorb the chemical stimuli of taste
- Stimuli is sent to the thalamus then to the insular cortex
- Sweet, bitter, salty, sour and umami
Hair Cells
Sensory receptors found in the inner ear for both the vestibular and auditory system
Impossible Figures
Figures that at first glance seem fine, then upon further inspection are geometrically and physically impossible
Inattentional Blindness
- The phenomenon of not seeing things in plain sight
- Illustrated by that video of a basketball being thrown around and a gorilla walking through the middle of it
Just Noticeable Difference (JND)
- The smallest amount of change needed to sense a stimuli
- Related to absolute threshold
ie. the absolute threshold is the JND from nothing
Kinesthetic System
Allows you to know where your body is positioned in space
Lateral Antagonism
- Occurs when neural activity in a cell is inhibited by surrounding cells
- Allows the retina to see relative amounts of light instead of absolute amounts of light
Lens
Fexible, translucent area of the eye that refracts light from the world to the retina
Light Adaption
The eye becoming insensitive to light to accommodate for bright conditions
Monocular Depth Cues
- Clues about distance given by either eye alone
- Uses motion parallax and pictorial depth cues
Motion Parallax
- Used in Monocular depth cues
- Objects seem to move at different rates depending on their distance from us
ie. closer objects seem to move faster than objects in the distance
Nearsightedness
- Near objects appear clear, but distant ones appear blurry
- Can be caused by the eye being too long, or light falling short of the retina
Olfactory System
- Sense of smell
- Only sense that does not convert in the thalamus
- Receptors are olfactory cilia, hairlike structures in the upper nasal pathway that send information to the brain
- Cells are highly specialized and can only react to a number of odours
Opponent Process Theory
- Relies on receptors making antagonistic responses to three pairs of colours
- green vs red, yellow vs blue, black vs white
Optic Chiasm
The point where optic nerves cross over and send signals to the opposite side of the brain
Optic Disk
Hole in the retina where optic nerve fibres exit the eye, causing a blind spot
Optical Illusion
Perceived reality is different from true reality
ie. Ponzos illusions, the Ames room and the Muller-Lyer effect
Parallel Processing
- Simultaneously taking different kinds of information from the same input
- The main visual pathway is divided to do this
- Magnocellular and parvocellular channels
Magnocellular Channel
Specialized pathway within the main visual pathway responsible for processing information regarding brightness
Parvocellular Channel
Specialized pathway within the main visual pathway responsible for perception of colour
Perception
Organization and interpretation of sensory input
Perceptual Constancy
- The tendency that objects keep the same size, shape, texture etc.
- This is why we can move around a room and still perceive the same things
Perceptual Hypothesis
A guess as to which distal stimuli is responsible for the proximal stimuli being senses
Perceptual Set
Being prepared to receive stimulus in a certain way
ie. expecting a needle to hurt might amp up the pain
Pheromones
- Hormones released by one organism in a species and can be received by another
- Species specific
Phi Phenomenon
An illusion of movement given by flashing pictures rapidly
ie. Felix the cat
Pictorial Depth Cues
- One clue used in monocular depth cues
- Used to give 2D images a 3D appearance
1. Height in plane
2. Linear perspective
3. Texture gradients
4. Interposition
5. Relative size
6. Light and shadow
Place Theory
- States the clochea only vibrate in certain areas which is how the brain interpreted frequency
- Hermann von Helmholtz
Prosopagnosia
- Inability to recognize faces, including ones own
- Could be caused by damage to receptors that are sensitive to facial inpur
Proximal Stimuli
- The image that falls on the retina
- “internal” stimuli that your eye “touches”
Psychophysics
Study of how physical stimuli gets translated into a sensory, psychological experience
Pupil
Opening in the centre of the eye that helps regulate the amount of light coming into the eye
Receptive Field of a Visual Cell
- Visual cells own visual field
- It will only respond to stimulus within its receptive field
Retina
Neural tissue at the back of the eye that absorbs light, processes images and sends visual information to the brain
Retinal Disparity
Objects project to slightly different parts of each retina, making each eye see a unique image
Reversible Figure
A figure where the foreground can become the background and vice versa
ie. the picture with the 2 dark faces and the white vase in the middle
Rods
- Specialized in night time and pheripheral vision
- Found most densely in the edges of the eyes
Saccades
Tiny eye movements that give hints about where ones attention is drawn
Sensation
Stimulation of sense organs
Sensory Adaption
Senses adapting to new stimuli to keep your body alert for changes in the environment that may lead to danger
ie. “Hey, that doesn’t smell like my regular stinky garbage! That smells like natural gas!”
Signal-Detection Theory
States that detecting a stimuli involves deciding whether or not to care as well as sensory processes, both of which are influenced by intensity of the stimulus
Simple Cells
Visual receptors that respond to specific shapes that fall within specific areas of their receptive fields
Subjective Contours
Perception of contours where none exist
ie. a birds eye view of 3 cakes with a slice cut out might look to form a triangle
Subliminal Perception
Processing stimuli without conscious awareness
Subtractive Colour Mixing
Creating colour by taking away certain wavelengths, those left over are the colour you will see
ie. mixing paint
Threshold
Dividing point between intensity where one can sense a difference in effect
Top-Down Processing
Progression from the whole object to its separate elements
Trichromatic Theory of Colour Vision
- Created by Thomas Young
- Eye has 3 types of receptors that have different sensitivities to certain wavelengths of light
- Receptors specialize in red, green or blue
- Colours mix in the eye to form other colours
Vestibular System
- Found in the inner ear, connected to the auditory system
- Uses same hair cells
- Focuses on balance by detecting fluid movements in the inner ear
Visual Agnosia
The inability to recognize objects
Weber’s Law
- Created by Ernst Weber
- States the size of a JND is proportionate to the intensity of a stimulus
ie. adding 10 pounds into a bag that weighs 5 pounds will feel a lot different than adding 10 pounds to a bag that weighs 50 pounds
Mel Goodale
- States vision serves 2 functions:
1. creates internal model of the external world (vision for perception)
2. controls actions that are directed at the external world (vision for action) - Each vision type has a different neural pathway:
1. Dorsal stream - vision for perception (what)
2. Ventral stream - vision for action (where)
Linda Bartoshuk
- Did research into supertasters, nontasters and medium tasters
- nontasters have about 1/4 of the tastebuds supertasters have
- supertasters have receptors that non tasters don’t, are are therefore much more sensitive to certain foods (sweet and bitter)
Hermann von Helmholtz
- Created Place Theory
- Modified the original Trichromatic colour theory
Linda Buck and Richard Axel
- Discovered there are over 1000 genes that contribute to our olfactory senses
- Each has an ability to detect a number of very specific odours
David Hubel and Torsten Wiesel
- Discovered that certain visual receptors are more sensitive to certain stimuli, hinting at the cells being specialized
- Identified simple cells and complex cells
Max Wertheimer
- Created Phi Phenomenon
- Believed in the Gestalt principles
Gustav Fechner
- Created Fechners Law
- Discovered JND
Ronald Melzack and Patrick Wall
- Created the Gate-Control theory of pain
- Melzack continued his research and created the McGill Pain Questionnaire and has also studied phantom limb
