Wk6 Flashcards
Perception
Making sense of what our senses tell us. It is not determined by an actual stimulus but our prediction and interpretation of it
Sensation
Stimulus-detection process where our sense organs respond to and translate environmental stimuli. The process by which our sensory system detects info from the outside world.
Psychophysics
Relationship between physical energy needed to notice a stimuli and sensory capabilities.
Absolute threshold
Minimum amount of physical energy needed to notice a stimulus
The difference threshold
Smallest difference between 2 stimuli that people can perceive 50% of the time.
Weber’s law
The just noticeable difference is directly proportional to magnitude of stimulus.
Signal detection theory
Judgements about the presence or absence of stimulus reflect the observers sensitivity to the stimulus and their response bias
Sensory receptors
Transform energy in the environment into neural impulses that can be interpreted by the brain.
Transduction
Process of converting physical energy into neural impulses.
Response bias
The individuals readiness to report detecting a stimulus when uncertain
Fechner’s law
The logarithmic relation between subjective and objective stimulus intensity.
Stevens power law
As the perceived intensity of a stimulus grows arithmetically the actual magnitude of the stimulus grows exponentially
Sensory adaptation
The tendency of sensory receptors to respond less to stimuli that continue without change.
Subliminal perception
Process that occurs outside of conscious awareness
2 processes that occur in the eye
- The cornea, pupil and lens focus light on the retina
- Retina transduces the visual image into neural impulses that are relayed to and interpreted by the brain
The cornea
A tough, transparent tissue covering the front of the eyeball - light enters through the cornea.
Aqueous humour
A chamber of fluid behind the cornea which supplies oxygen and other nutrients to the cornea and lens.
Pupil
An opening in the centre of the iris
Iris
The pigmented tissue that gives the eye its colour. Muscles fibres in the iris cause the pupil to expand and contract to regulate the amount of light coming into the eye.
Lens
Elastic, disc-shaped structure involved in focusing the eyes. Muscles attached to cells surrounding the lens alter its shape to focus on objects at varying distances.
Accommodation of the lens
Flattens for distant objects and rounded for closer.
Retina
A light-sensitive layer of tissue at the back of the eye that transduces light into visual sensations
Rods and cones
Light receptors at the back of the retina, when they absorb light they generate an electrical signal stimulating the nearby bipolar cells. There are 120 million rods and 8 million cones.
Bipolar cells
Combine the info from many receptors and produce graded potentials on ganglion cells.
Ganglion cells
Integrate info from bipolar cells The axons bundle together to form the optic nerve.
Optic nerve
Carries visual info to the brain.
Fovea
Central region of the retina - most sensitive to small detail so vision is sharpest for stimuli directly in sight
Blind spot
Point on the retina where optic nerve leaves the eye has no receptor cells
Receptive field
Region within which a neuron responds to appropriate stimulation
Blindsight
People are unaware of their ability to see
Feature detectors
Neurons that fire only when stimulation in their receptive field matches a very specific pattern
The What pathway
Involved in determining what an object is.
The Where pathway
Involved in locating objects in space.
Young-Helmholtz theory of colour
Eye contains 3 types of receptors, each maximally sensitive to wavelengths of light that produce sensations of blue, green or red.
Short wavelengths of colour
Blue
Middle wavelengths of colour
Green
Long wavelengths of colour
Red
Opponent process theory
All colours are derived from 3 antagonistic colour systems - black-white, blue-yellow, and red-green
Parallel processing
brain cell teams process combined info about colour, movement, form and depth
Retinal processing
receptor rods and cones - bipolar cells - ganglion cells
Complexity
The extent to which a sound is composed of multiple frequencies and corresponds to the psychological property of timbre or texture of sound.
The middle ear
Eardrum - thin flexible membrane at the outer boundary.
The inner ear
2 sets of fluid filled cavities hollowed out of the temporal bone of the skull - the semicircular canal (balance) and the cochlea (hearing)
Place theory
Different areas of the basilar membrane are meximally sensitive to different frequencies.
Place theory
Different areas of the basilar membrane are maximally sensitive to different frequencies.
Frequency theory
The more frequently a sound wave cycles, the more frequently the basilar membrane vibrates and its hair cells fire, thus pitch perception is mediated by 2 neutral mechanisms - place code at high frequencies and at low.
Hair cells
Attached to the basilar membrane then transduce the sound, triggering firing if the sensory neurons whose axons comprise the auditory nerve.
Sound localisation
Identifying the location of a sound in space
Olfactory epithelium
A thin pair of structures in the area at the top of the nasal cavities where the transduction of smells occurs
Olfactory nerve
Transmits info to the olfactory bulbs, multilayered structures that combine info from the receptor cells
Gate-control theory
Emphasises the role of the central nervous system in regulating pain.
Proprioceptive sense
Register the body position and movement
Vestibular sense
Provides info about the position of the body in space by sensing gravity and movement
Kinaesthesia
Provides info about the movement and position of the limbs and other parts of the body relative to one another.
Gestalt principles
Argue that the whole is more than the sum of its parts (top-down)
Figure-ground relations
The organisation of stimuli into a foreground figure and a background
Gestalt perceptual law
Similarity - Brain groups similar elements together
Proximity - Briain groups objects that are close together
Good continuation - Brain organises stimuli into continuous lines or patterns
Simplicity - Ppl perceive the simplest pattern possible
Closure - Ppl perceive incomplete figures as complete
Recognition-by-components
We perceive and categorise objects in our environemnt by breaking them down into component parts and then matching them and the way they are arranged against similar sketches stored in memory
Perceptual illusions
Normal perceptual processes produce perceptual misinterpretations
Perceptual constancy
Perception of objects as relatively stable despite changes in the stimulation of sensory receptors.
Size constancy
Objects do not appear to change in size when viewed from different distances.
Muller-lyer illusion
Two lines of equal length appear to differ in size
Colour constancy
Tendency to perceive the colour of objects as stable despite changing illumination
Shape constancy
Maintain constant perception of the shape of objects despite the fact that the same object typically produces a new and different impression on the retina every time we encounter it.
Perceptual interpretation
Generating meaning from sensory experience
Bottom-up processing
Processing that begins at the bottom with raw sensory data that feed up to the brain.
Top-down processing
Starts at the top with the observers expectations and knowledge.
