Sensation and Perception Flashcards
Sensation vs. Perception
Sensation: the detection of physical energy emitted or reflected by physical objects
Perception: the way the brain organizes and interprets sensory information (into meaningful patterns)
How do we have more than 5 senses?
The skin senses heat, cold, pain, itch, etc.
The ear has receptors that sense balance
Skeletal muscles have receptors that sense bodily movement
Sense receptors
Cells in sense organs that convert physical energy to electrical energy that can be transmitted as impulses to the brain
Doctrine of specific nerve energies (person, date, solves what question?, content)
Johannes Müller, 1826
Solves question of how the brain can different sensations.
Content: signals from sense organs stimulate different nerve pathways, which lead to different areas of the brain
Synesthesia. Most common form?
A condition where sensation in one modality evokes a sensation in another.
Most common form: people experience certain colors when seeing specific letters or numbers.
Absolute Threshold, Difference Threshold
Absolute Threshold: the smallest amount of energy that someone can detect 50% of the time
Difference Threshold: the smallest difference in simulation that can be detected 50% of the time
50% of the time = reliable
Weber’s law
difference thresholds are by a fixed proportion (not a certain amount)
Signal-detection theory
A theory that divides detection of sensory signal into a sensory and decision process.
Adjusts for response bias in difference/absolute threshold perception
Sensory Adaptation
Reduction or disappearance of sensory responsiveness when simulation is repeated/unchanging
Selective Attention, Inattentional Blindness
Selective attention: The ability to focus on some parts of our environment and block out others.
Inattentional blindness: Failure to consciously perceive something that we’re looking at (eg. gorilla)
3 Psychological Dimensions of Vision
Hue: wavelength of light (specified by color names)
Brightness: amplitude; intensity of light.
Saturation: range of wavelengths; complexity of light
Trace the path of light into the eye.
First enters through cornea, then bends light towards lens behind it. The lens changes its shape, then focuses light based on distance.
Iris controls amount of light into eye, giving color. Surrounds pupil of the eye (the round opening).
Visual receptors of eye is located
Retina, at the back of the eye.
2 receptors in the retina (how many of each?)
Rods: 80 to 120 million
Cones: 5 to 7 million
Fovea. Which type of receptor is present in fovea?
The center of the retina where vision is sharpest. Only cones.
Which receptor enables us to see in dim light?
Rods. More sensitive to light.
Which receptor enables us to distinguish colors? How?
Cones. They are sensitive to specific wavelengths, while rods cannot distinguish different wavelengths.
Dark Adaptation
how long for rods? what about cones?
The process of visual receptors becoming sensitive to dim light.
Rods take 20 mins, cones around 10 min (but not ver sensitive)
Ganglion cells
Neurons in the retina that gather info from receptor cells, where optic nerve is formed.
Feature-detector cells
Cells in visual cortex that are sensitive to specific features in the environment. (while ganglion are for more simple things like dark/light)
Trichromatic Theory (what alternative name?)
Young-Helmholtz theory
There exists 3 types of cones, responding maximally to blue/green/red. These 3 cones make the thousands of colors we see.
Opponent-process theory
2nd stage. Color perception where visual system treats pairs of colors as opposing. There exists antagonistic colors. Afterimages of opposing colors give evidence for this.
Gestalt Principles in perception
Principles that describe how the brain organizes information into meaningful units
Binocular cues
Visual cues that require the use of both eyes
Convergence
the turning of eyes inward to focus on a nearby object.
Retinal disparity
A slight difference in lateral separation between two objects seen by left and right eye
Monocular cues
Visual cues that only need one eye
Interposition
First object that is in front of second object is perceived as being closer
Linear perspective
Two parallel lines that are converging in a distance imply the distance.
Perceptual constancy
When objects are perceived as same even as sensory information change. (size, shape, location, brightness, color)
When do perceptual illusions happen?
When we have systematic errors in our perceptual strategies.
What is white noise?
All frequencies on the audible sound spectrum
How would hearing be without the outer ear?
Still pretty good
Sound wave passes through what to strike an oval shaped membrane called what?
Passes through ear canal to strike eardrum.
Where do vibrations go after eardrum? Function?
3 tiny bones (hammer, anvil, and stirrup). They enhance the vibration. Stirrup opens up membrane into inner ear
Organ of Corti
Structure inside cochlea with hair cells, which are receptors for hearing
Cochlea
Snail-shaped in inner ear, filled with fluid, contains organ of Corti
How are auditory signals passed on to the brain?
Hair cells brush against membrane, then pass to auditory nerve to carry to brain.
Gustation
taste
Papillae
tiny elevations on the tongue, containing taste buds
Taste buds
nests of taste receptor cells (50 to 150 in each bud)
At what age do taste buds decline?
After age 40
6 basic tastes (debatable)
sweet, sour, bitter, salty, umami, oleogustus
gate-control theory
pain messages are blocked by a gate, then the gate is released when some stimulation happens.
Phantom pain
pain in a missing limb or body part (eg. rubber arm, amputated arm, etc.)
Kinesthesis
Sense of body position and movement of body parts
Equilibrium (in sensation)
The sense of balance
Semicircular canals
Sense organs in the inner ear that contribute to equilibrium by responding to head rotation.
