Studied by 2 peopleheuristics are...
rules-of-thumb that can be applied to guide decision-making based on a more limited subset of the available information
The brain continuously makes predictions about the world and tests these against ______________
sensory evidence
the brain has evolved to __________
reconstruct reality in a way that is useful to us
one way to learn how a complex system is organised is...
by studying situations where it makes mistakes
mental life gets more complex with more ______
sensory stimuli
Define psychophysics
scientific method for investigation of relationships between physical stimuli and psychological experience
The "absolute threshold" is...
the smallest amount of stimulation needed for a person to detect that stimulus 50% of the time
Example of absolute sensory threshold: Vision
candle flame 30 miles away on a dark, clear night
Example of absolute sensory threshold: Hearing
a clock's tick 20 feet away when all is quiet
Example of absolute sensory threshold: Touch
a fly's wing falling on the cheek from 1 cm away
Example of absolute sensory threshold: Smell
a single drop of perfume diffused through an area equivalent to the volume of six rooms
Define difference threshold.
the minimum difference in stimulus intensity necessary to tell two stimuli apart
What is another name for the difference threshold?
just noticeable difference (JND)
What is the difference threshold or JND dependent on?
the magnitude of the stimuli
Weber-Fechner law:
CHANGE in INTENSITY over INTENSITY equals WEBER FRACTION (K)
Weber-Fechner law states that...
JND is a constant proportion of standard stimulus intensity
Weber fraction - light intensity
0.079
Weber fraction - sound intensity
0.048
Weber fraction - salt taste
0.083
Psychophysics marked the beginning of ___________
experimental psychology
Define signal detection theory.
a method of differentiating a person's ability to discriminate the presence and absence of a stimulus (or different stimulus intensities) from the criterion the person uses to make responses to those stimuli.
Hits are ______
identifying correct stimulus
A false alarm is when _______
subject identifies stimulus but there is no stimulus there
Light is ______
the visual part of the electromagnetic spectrum
Define visual acuity.
The ability to see fine detail
Visible light is ________
The portion of electromagnetic spectrum seen
Colour _______ exist in the outside world
does
Colour _________ exist in the outside world
doesn't
The lens of an eye expands and contracts to ____________
control how light falls on the retina
The optic nerve has ______
photoreceptors
There are no photoreceptors in the _________
blind spot
retinal image is ________ in passing through the lens
inverted
topographic meaning
map like -> reflects real world spatial relationships
visual signals relay to primary visual cortex via ___________
lateral geniculate nucleus
Receptive field
Region of sensory surface that, when stimulated, causes a change in the firing rate of that neuron
The visual system represents the world __________
Topographically
The basic elements within the visual world (e.g. edges, colour, movement) are delivered by ________
bottom-up hierarchical processes
feature detectors are _________
the building blocks of perception
Our feature detectors are wired to _______
detect changes
the brain can solve complex tasks by _________
breaking them down into many, much simpler sub-tasks
High-level phenomena can be understood in terms of _____
simple low-level mechanisms
motions perception is _______
relative
space constancy is __________
when we factor out self-generated movement, to perceive only movement arising in the world
motion is a powerful cue for __________
alerting, orienting and for form perception
perceptual constancies mean we can see real, unchanging properties in the world despite _____________
LARGE changes in stimulation
What does colour vision do for us?
helps us classify and identify objects
is important signalling mechanism in nature
facilitates perceptual organisation of scene into distinct objects
The colour of an object or substance is determined by __________________
the wavelengths of light that it reflects (or that pass through it)
There are two basic classes of ___________
Photoreceptor
What are the two basic classes of photoreceptor?
rods and cones
Modalities
sensory brain regions that process different components of the perceptual world
sensation
simple awareness due to the stimulation of a sense organ
perception
the organisation, identification and interpretation of a sensation in order to form a mental representation
transduction
what takes place when many senses in the body convert physical signals from the body into neural signals sent to the central nervous system.
D prime (D')
A statistic that gives a relatively pure measure of the observer's sensitivity or ability to detect signals
Sensory adaptation
sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions
retina
light-sensitive tissue lining thew back of the eyeball
accomodation
the process by which the eye maintains a clear image on the retina
Cones
photoreceptors that detect colour, operate under normal daylight conditions and allow us to focus on fine detail
Rods
photoreceptors that only become active under low light conditions for night vision
Fovea
an area of the retina where vision is the clearest and there are no rods at all
Trichromatic Colour Representation
the pattern of responding across the three types of cones that provides a unique code for each colour
colour opponent system
pairs of visual neurons that work in opposition
Area v1
the initial processing region of the primary visual cortex
topographic visual organisation
adjacent neurons process adjacent portions of the visual field
visual form agnosia
the inability to recognise objects by sight
affordances
potentials for possible actions by agents acting on the environment
binding problem
how features are linked together so that we see unified objects in our visual world rather than free floating or miscombined features
illusory conjunction
a perceptual mistake where features from multiple objects are incorrectly combined
feature integration theory
a theory that proposes that attention binds individual features together to comprise a composite stimulus
synaesthesia
the perceptual experience of one sense that is evoked by another sense
modularisation
the process of relatively encapsulated function
perceptual constancy
a perceptual principle that even as aspects of sensory signals change, perception remains constant
template
a mental representation that can be directly compared to a viewed shape in the retinal image
structural enconding
how a pattern is represented
monocular depth cues
aspects of a scene that yield information about depth when viewed with only one eye
binocular disparity
the difference in the retinal image of the two eyes that provides information about depth
motion parallax
a depth cue based on the movement of the head over time
apparent motion
the perception of movement as a result of alternating signals appearing in rapid succession in different locations
pitch
how high or low a sound is
loudness
a sound's intensity
timbre
a listener's experience of sound quality or resonance
cochlea
a fluid-filled tube that is in the organ of auditory transduction
basilar membrane
a structure in the inner ear that undulates when vibrations from the ossicles reach the cochlear fluid
hair cells
specialised auditory receptor neurons embedded in the basilar membrain
area a1
a protion of the temporal lobe that contains the primary auditory complex
place code
the cochlea encodes different frequencies at different locations along the basilar membrane
temporal code
the cochlea registers low frequencies via the firing rate of action potentials entering the suditory nerve
visual orienting
a behavioural response to move the eye towards a target
multisensory integration
the perceptual representation of events from more than one sensory modality
haptic perception
the active exploration on the environment by touching and grasping objects with our hands
referred pain
feeling of pain when sensory information from internal and external areas converge on the same nerve cells in the spinal cord.
gate-control theory
a theory of pain perception based on the idea that signals arriving from pain receptors in the body can be stopped, or gated, by interneurons in the spinal cord via feedback from two directions
vestibular system
the three fluid-filled semicircular canals and the adjacent organs located next to the cochlea in each inner ear
olfactory receptor neurons (orns)
receptor cells that initiate the sense of smell
olfactory bulb
a brain structure located above the nasal cavity beneath the frontal lobes
pheromones
biochemical odourants emitted by other members of their species that can affect an animal's behaviour or psychology
taste buds
the organ of taste transduction
neural coding of colour is an _______
opponent process
chromatic adaptation ___________
reduces our sensitivity to the dominant wavelengths in the light within our current environment
colour constancy
our tendency to perceive an object as the same colour, across changes to illumination
Note
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