Unit 4 Flashcards
Sensation
the process of detecting the external events by the sense organs
Transduction
process in which or chemical stimulation is converted into a neural impulse that is relayed to the brain
Perception
involves attending to, organizing and interpreting stimuli that we sense
Types of stimulus thresholds
Absolute threshold and difference treshold
Absolute threshold
the minimum amount of energy or quantity of a
stimulus required for it to be reliably detected at least 50% of the time it
is presented
Difference threshold
the smallest detectable difference between stimuli
Signal detection theory
States whether a stimulus is perceived
depends on both sensory experience and judgment made by the subject
Subliminal stimuli
presented to a person below their conscious threshold
We detect subliminal stimuli without conscious awareness
- activation in certain brain regions
Gestalt principles of perception
Figure-ground principle, proximity, similarity, continuity, and closure
Figure-ground principle
objects and figures in our environment tend to stand out against a background
Proximity
objects in close proximity tend to treated as a group
Similarity
objects of similar shape, colour, or orientation tend to be grouped
Continuity
items seen as whole figures, even if broken into segments
Closure
we fill in the gaps to complete a whole
Top-down processing
occurs when prior knowledge and expectations guide what is perceived
Bottom-up processing
is constructing a whole stimulus or concept from bits of raw sensory information
Selective attention
involves focusing on one particular event or task
Divided attention
involves paying attention to several stimuli or tasks at once
Inattentional blindness
a failure to notice clearly visible events or objects because attention is directed elsewhere
Basic structure of the eye
Sclera, cornea, pupil, iris, and lens
Sclera
White outer layer of eye
Cornea
Clear layer that covers the front of the eye
Pupil
Regulates amount of light let into eye
Iris
Round muscle that adjusts the size of the pupil
Lens
clear structure that focuses light onto the back of the eye
Parts of the retina
Cones (with fovea), and rods
Cones
photoreceptors sensitive to wavelengths of light we perceive as colour; active in normal lighting conditions
Fovea
cone rich region in the center of the retina on which light is focused
Rods
photoreceptors on periphery of retina that are highly sensitive to low light levels
Dark adaption
the process by which rods and cones gain sensitivity to low light levels
Parts of the optic nerve
Bipolar neurons, ganglion cells, optic disc, and optic nerve
Bipolar neurons function
synapse onto photoreceptors
Ganglion cells function
transmits signals from bipolar neurons to brain
Optic disc
area on retina lacking rods and cones
Optic nerve
axon tracts from ganglion cells leading to brain
Common visual disorders
nearsighted, farsighted, and colourblindness
Trichromatic theory
maintains that colour vision is determined by three different cone types that are sensitive to short, medium, and long wavelength light (colour)
Opponent-process theory
states that we perceive colour in terms of opposite ends of the spectrum (red to green, yellow to blue, white to black)
Ganglion cells provide…
three colour ‘channels’
Negative afterimages
After prolonged fixation, residual image seen with opposite colour
If based on trichromatic theory, colourblind individuals should not…
see yellow
Retinal neurons…
interact to organize visual information
Horizontal cells
laterally connecting inhibitory interneurons (GABA releasing)
Optic chiasm
crossover point for optic nerve at midpoint of the brain
Lateral geniculate nucleus
region within thalamus that directs visual information throughout the brain
Feature detection cells
neurons that respond selectively based on specific aspects of a stimulus (e.g., angles and edges) as well as to specific regions of the visual field.
Ventral stream
extends from visual cortex to temporal lobe
Responsible for object and face recognition
Fusiform face area
Greeble experiment
fusiform face area responsible for visual expertise
Perceptual constancy
the ability to perceive objects as having constant shape, size, and colour despite changes in perspective
Size constancy depends on…
other depth cues to make perceptual connections
Lightness constancy
Maintain perception under uneven illumination
Dorsal stream
Extends from visual cortex to parietal lobe
Responsible for depth and motion perception
Binocular depth cues
distance cues that are based on the differing perspectives of both eyes
Convergence
occurs when the eye muscles contract so that both eyes focus on a single object
Retinal disparity
the difference in relative position of an object as seen by both eyes
Parts of monocular depth cues
Accommodation, and motion parallax
Monocular depth cues
these are depth cues that we can perceive with only one eye
Accommodation
curving of lens to focus on nearby objects
Motion parallax
used when surroundings are in motion
Parts of sound
Pitch and loudness
Pitch
perceptual experience of sound wave frequencies
loudness
perceptual experience of amplitude
Basic parts of the human ear
Outer ear, middle ear, and inner ear
Outer ear parts
pinna, auditory canal, eardrum
Middle ear parts
ossicles (malleus, incus, stapes)
Inner ear parts
Cochlea
Place theory of hearing
how we perceive pitch is based on the location (place) along the basilar membrane that sound stimulates
Frequency theory
states the perception of pitch is related to the frequency at which the basilar membrane vibrates
Volley theory
neurons fire in rapid succession
Medial geniculate nucleus
structure within thalamus responsible for routing of auditory information
Primary auditiory cortex
major perceptual center of the brain involved in perceiving what we hear
Multimodal integration
combining sensations from different modalities into single integrated perception
McGurl effect
Occurs in the midbrain by the superior (visual) and inferior (auditory) colliculi
Soud localization
process of identifying where sound comes from
Controlled by the inferior
Sound localization is achieved by…
Interaural time differences and Sound shadow
What is used to perceive sense of touch
Mechanoreceptors, and nociceptors
Mechanoreceptors
detect pressure and touch
Nociceptors
detect heat and pain
Acuity
ability to discern to points of pressure
Haptics
active, exploratory aspect of touch sensation and perception
Kinesthetics
our sense of bodily motion and position
Nociception
the activity of the nerve pathways that respond to uncomfortable stimulation
Nociceptors
free nerve endings that detect pain
Gate-control theory
explains our experience of pain as an interaction between nerves that transmit pain messages and those that inhibit these messages
___ has a subjective component
pain
Gustatory system
Taste system
Receptors for taste are located on ____ (__) that cover the tongue
small bumps (papillae)
Projections for taste go to ___ to ____
thalamus to gustatory cortex
Pro tasters
Can have many times the typical number (10,000) of taste buds of average people
Olfactory system
smell
Olfactory epithelium
thin layer of cells that are lined by sensory receptors called cilia
Cilia transmit tranduced signal to the olfactory ____ via the ___
olfactory bulb via the olfactory tract
