sensation and perception
Sensation: Gathering Information
Perception: Interpreting Information
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Senses and the World
Stimuli: something external that promotes a physical response
Sensory neurons are continually inundated with stimuli
Senses:
Sight- Visual Sense
Hearing - Auditory Sense
Taste- Gustation (Taste)
Touch- Touch Sense
Smell- Olfactory Sense
Sensation and Perception
Sensation:
The processes by which our sense organs receive information from the environment
Transduction:
The process by which physical energy is converted into sensory neural impulses
Perception:
The process by which people select, organize, and interpret sensations
Sensation and Perception Processes
Sensation:
Stimulus Detection: Sensory organs (e.g., eyes, ears, skin) detect external stimuli (light, sound, touch, etc.).
Transduction: Sensory receptors convert the physical stimuli into electrical signals.
Transmission: The electrical signals are sent to the brain via the nervous system.
Perception:
Organization: The brain organizes the incoming sensory data.
Interpretation: The brain interprets the data based on past experiences, knowledge, and context.
Perceptual Experience: The brain creates a conscious experience (e.g., seeing a face, hearing music, feeling an object).
Coding
The process in which neural impulses:
Travel by different routes To different parts of the brain
Allowing us to detect different types of physical stimuli as different sensations
Feature Detectors = Specialized Neurons
The brains of humans and other animals contain specialized neurons (cells)
Respond only to certain sensory information and maximally to face
Vision
Your eye has two types of sensory receptors:
Rods: are active in Dim lighting
Cones: responsible for color vision and fine detail
Trichromatic Theory
T. Young (1802) & H. Von Helmholtz (1852)
Both proposed that the cones in the eye detect 3 primary colors: red, blue, green
Said all other colors can be derived by combining these 3
The Color Wheel
Spectral colors vary from violet-blue to red
Opponent colors are directly across from each other on the wheel
Opponent-Process Theory:
Color vision comes from 3 pairs of opposing receptors
The opponent colors are blue and yellow, red and green, and black and white
This theory explains afterimages and color deficiency
Afterimage:
Image you see after staring at something
For example: when you look at a projector light and then look away
Optic nerve: Pathway that carries visual information from the eyeball to the brain
Retina: Light sensitive inner surface of the back of they eye, which contains the receptor cells for vision
Hearing
Audition: the sense of hearing
Outer Ear: the pinna, auditory canal, and eardrum structures, which funnel sound waves to the middle ear
Middle Ear: The hammer, anvil and stirrup structures of the ear, which concentrate eardrum vibrations onto the cochleas oval window
Inner Ear: The semicircular canals, vestibular sacs, and cochlea, which generate neural signals that are sent to the brain
Cochlea: the fluid-filled, coiled tube in the inner ear that contains the receptors for hearing
Place theory for hearing: the theory the pitch perception is linked to the particular spot on the cochleas basilar membrane that is most stimulated
Frequency theory for hearing: The theory that pitch perception depend on how often the auditory nerve fires
Volley principle for hearing: An explanation for pitch perception suggesting that clusters of neurons take turns firing in a sequence of rhythmic volleys, and that pitch depends on the frequencies of these volleys.
Conduction hearing loss: a type of hearing loss that results from damage to the mechanical system that conducts sound waves to the cochlea; also called conduction deafness
Sensory hearing loss: A type of hearing loss resulting from damage to the cochleas receptor (hair) hearing cells or to the auditory nerve; also called nerve deafness
Auditory Localization
The ability to judge from which direction a sound is coming
Sounds from different directions are not identical as they arrive at left and right ears
The brain calculates a sounds location by using differences in timing and intensity
Smell
Olfactory System: Structures responsible for the sense of smell
Sense of Taste
Taste Buds: nets of taste receptor cells
Gustation: The sense or act of tasting; receptores are located in the tongues taste buds
Selective Adaptation = Habituation
A decline in sensitivity
To a stimulus due to constant exposure to it
Example: trains, sirens, loud talking
Vision Cues = Vision Input
Allows perception of depth and distance
Depth Perception: The ability to perceive 3 dimensional space and judge distance
Binocular Cues: Visual input from 2 eyes
Monocular Cues: Visual input from 1 eye
Perception
Perception:
Perceptual organization
Perceptual constancies
Depth and Dimension
Perceptual Set
The World of Illusions
Perceptual Processing
Bottom up processing: A, B, C, D..
Begins at the bottom
Raw sensory data is sent from the bottom up to the brain
For higher processing
Example: learning letters before learning words, then “reading”
Top Down Processing:
Begins at the top
The brain uses existing knowledge, beliefs, and expectations to interpret the sensory stimulation
Example: can make sense when typos are not actual words
Gestalt Principles of Organization
Similarity- Objects that are alike are considered to be a unit
Proximity- because of spacing objects considered a unit
Closure- the tendency to fill in the gap to produce a familiar object
Identifying Objects
Geons: (geometric icons) are simple 3D component shapes
A limited number are stored in memory
Geons are combined to identify essential contours of objects
Perceptual Constancies
Size Constancy: the tendency to view an object as a constant in size despite changes in the size of the object
Shape Constancy: The tendency to see an object as keeping its form despite changes in orientation
The Ames Room:
A specially built room that makes people seem to change size as they move around in it
The room is not a rectangle, as viewers assume it is
A single peephole prevents using binocular depth cues
Depth and Dimension
The Visual Cliff
Devised by Eleanor Gibson and Richard Walk to test depth perception in infants and animals
Provides visual illusion of a cliff
Caregiver stands across the gap
Babies are not afraid to cross it until about the age they can crawl
The World of Illusions
The Müller-Lyer Illusion:
Illusion in which the perceived length of a line is altered by the position of other lines that inclose it
The Ponzo Illusion
Illusion in which the perceive line length is affected by linear perspective cues
Side lines seem to converge
Top line seems farther away
Convergence (Binocular Cue)
Turning eyes inward to fixate on the object
To interpret distance as an object gets closer
Monocular Depth Cues
Relative Image Size:
close objects cast a larger image than distant objects
If two objects are roughly the same size, the object that looks the largest will be judged as being the closest to the observer
Texture Gradient:
Nearby objects have a coarser, more distinct texture than distant ones
Linear Perspective:
Parallel lines converge/move toward one another, as they recede/go into the distance
Aerial Perspective:
Distant objects appear hazy and blurred
Parapsychology
Parapsychology:
Psychology is the study of human behavior and mental processes
“Para” psychology means closely related to, or a departure from the normal
The field of psychology that studies phenomenon that fall outside the normal realm of psychology
Extrasensory Perception (ESP)
The ability to perceive something without ordinary sensory information
This has not been scientifically demonstrated
Types of ESP:
Telepathy: mind-to-mind communication
Clairvoyance: perception of remote (far away) events
Precognition: the ability to see future events before they happen