Chapter 4 Flashcards
What is audiology?
Science concerned with hearing
What is ophthalmology?
Study of the eye’s structure, function and diseases
What are sensation and perception?
Processes through which we detect and understand different types of stimuli
What is perception?
Process of organizing and interpreting sensory information
What is sensation?
Process of receiving energy from stimuli in our internal or external environment and transforming this energy into action potentials
What is transduction?
The process by which a specialized receptor cell converts energy from an external stimulus (e.g., light, sound, heat) to an internal electrical signal (action potentials).
What are the three things sensory systems have in common?
Specialized receptor cells, transduction and multiple subsystems
Differentiate between bottom up and top down processing
Bottom-up processing: sensory receptors register information about the external environment and send it up to the brain for interpretation
Top down processing: Begins with some sense of what is happening due to past experiences and applies it to incoming information
How are sensory receptors connected to the brain?
Sensory receptors detect stimulus and transmit it to afferent (sensory) nerves which bring the information to the brain
List the different types of sensory receptors, type of energy reception and sense organ
Vision: photoreception (detection of light): eyes
Hearing: mechanoreception (detection of vibration): ears
Touch: mechanoreception (detection of pressure): skin
Smell: Chemoreception (detection of chemical stimuli): nose
Taste: Chemoreception (detection of chemical stimuli): tongue
Define absolute threshold
minimum amount of stimulus energy that a person can detect
Define difference threshold
The degree of difference that must exist between two stimuli before the difference is detected.
What is Weber’s law?
The principle that two stimuli must differ by a constant minimum percentage (rather than a constant amount) to be perceived as different.
Define subliminal perception
The detection of information below the level of conscious awareness.
Signal detection theory
An approach to perception that focuses on decision making about stimuli under conditions of uncertainty.
Define attention
The process of focusing awareness on a narrow aspect of the environment.
Define selective attention
The act of focusing on a specific aspect of experience while ignoring others.
Define sensory adaptation
A change in the responsiveness of the sensory system to the average level of stimulation.
What is light?
A form of electromagnetic energy that can be described in terms of wavelengths: 400 - 700 nm
Do light waves of greater or smaller amplitude make brighter light?
greater
What two structures in the eye bring an image into focus and how?
The cornea and lens bend the light falling on the surface of eye to bring an image into focus
What is a retina
The multilayered, light-sensitive surface in the eye that records electromagnetic energy and converts it to neural impulses for processing in the brain.
What are two kinds of visual receptor cells and how do they differ in how they respond to light
Rods and cones. Rods locating in retina and are very light sensitive - work well at night
Cones are used for colour perception and operate best during the day
What is the fovea?
tiny area in the centre of the retina that allows us to see fine details
Are rods or cones located on the fovea?
Cones
Define optic nerves
The structure at the back of the eye, made up of axons of the ganglion cells, that carries visual information to the brain for further processing.
What is the visual cortex?
Located in the occipital lobe - major part of cerebral cortex and is used for vision where visual information is processed
What are feature detectors
Neurons in the brain’s visual system that respond to particular features of a stimulus.
How is sensory information processed so quickly
Parallel processing: The simultaneous distribution of information across different neural pathways.
Define trichromatic theory
Theory stating that colour perception is produced by three types of cone receptors in the retina that are particularly sensitive to different, but overlapping, ranges of wavelengths.
What did young and helmholtz reason?
If the combination of any three wavelengths of different intensities is indistinguishable from any single pure wavelength, the visual system must base its perception of colour on the relative responses of three receptor systems - cones sensitive to red, blue and green
What is the opponent process theory
Theory stating that cells in the visual system respond to complementary pairs of red-green and blue-yellow colours; a given cell might be excited by red and inhibited by green, whereas another cell might be excited by yellow and inhibited by blue.
Define figure-ground relationship
The principle by which we organize the perceptual field into stimuli that stand out (figure) and those that are left over (ground).
Define Gestalt psychology
A school of thought that arose amongst German and Austrian psychologists in the early 1900s to explain how people naturally organize their perceptions according to certain patterns.
What are the three main principles of gestalt
Closure: When we view disconnected or incomplete figures, we fill in the spaces and see them as complete figures
Proximity: When we view objects that are near each other, they tend to be seen as a unit
Similarity: When we view objects that are similar to each other, they tend to be seen as a unit
Define depth perception
The ability to perceive objects three-dimensionally and perceive their distance from you.
Define binocular cues
Depth cues that depend on the combination of the images in the left and right eye and on the way the two eyes work together.
Define convergence
A binocular cue to depth and distance in which the muscle movements in an individual’s two eyes provide information about how deep and/or far away something is.
Define monocular depth cues
Powerful depth cues available from the image in one eye, either the right or the left.
Define apparent movement
The perception that a stationary object is moving.
Examples of monocular cues
Familiar size, height in the field of view, linear perspective, overlap, shading, clarity, texture gradient
define perceptual constancy
The recognition that objects are constant and unchanging even though sensory input about them is changing.
Three types of perceptual constancy
Size, shape and colour constancy
Sound wave amplitude
Amount of pressure the sound wave produces
How many parts is the ear divided into
3
Outer, middle, inner ear
What does the outer ear consist of
The outermost part of the ear, consisting of the pinna and the external auditory canal.
Function of pinna
funnels sound into the interior of the ear
What does the middle ear consist of
The part of the ear that channels sound through the eardrum, hammer, anvil, and stirrup to the inner ear.
What does the inner ear consist of
The part of the ear that includes the oval window, cochlea, and basilar membrane and whose function is to convert sound waves into neural impulses and send them to the brain.
Definition of place theory
Theory on how the inner ear registers the frequency of sound, stating that each frequency produces vibrations at a particular spot on the basilar membrane.
Define frequency theory
Theory on how the inner ear registers the frequency of sound, stating that the perception of a sound’s frequency depends on how often the auditory nerve fires.
Define volley principle
Modification of frequency theory stating that a cluster of nerve cells can fire neural impulses in rapid succession, producing a volley of impulses.
How does the brain process auditory information
Auditory nerve: The nerve structure that receives information about sound from the hair cells of the inner ear and carries these neural impulses to the brain’s auditory areas.
What are tactile receptors
Receptors where sensations from them are perceived as pain
Fast and slow pathways
Fast pathway: Myelinated A-delta fibres connect directly with the thalamus and then to the motor and sensory areas of the cerebral cortex; sharp localized pain
Slow pathway: Un-myelinated C-delta fibres transmit pain information through the limbic system; delays information by seconds
What are papillae
Rounded bumps above the tongue’s surface that contain the taste buds, the receptors for taste.
Define olfactory epithelium
The lining of the roof of the nasal cavity, containing a sheet of receptor cells for smell.
What are kinesthetic senses
Senses that provide information about movement, posture, and orientation.
What are vestibular sense
Sense that provides information about balance and movement.
Define semicircular canals
Three fluid-filled circular tubes in the inner ear containing the sensory receptors that detect head motion caused when an individual tilts or moves the head and/or the body.
What is located at the base of the semicircular canals
Two organs—the utricle and saccule—that detect sustained changes in head position such as a tilt of the head to the left or right.
