Psych1011 WEEKS 9+10 Flashcards
Sensation and Perception
PERCEPTION
The brain’s interpretation of raw sensory input.
SENSATION
Detection of physical energy by sense organs which then send info to the brain.
ILLUSION
Perception in which the way we perceive a stimulus doesn’t match physical reality.
TRANSDUCTION
The process by which the nervous system converts an external stimulus (like light or sound) into electrical signals within neurons.
SENSE RECEPTOR
Specialised cell responsible for converting external stimuli into neural activity for a specific sensory system.
SENSORY ADAPATION
Activation is greatest when a stimulus is first detected.
Level of sense receptor.
PSYCHOPHYSICS
The study of how we perceive sensory stimuli based on their physical characteristics.
Gustav Fechner, 1860.
ABSOLUTE THRESHOLD
Lowest level of stimulus needed for the nervous system to detect it, 50% of the time.
Lowest level of light, sound, etc.
WEBER’S LAW
There is a constant proportional relationship between the Just Noticable Difference and the strength of the stimulus.
→ The stronger the stimulus the bigger the changed needed.
Weber’s constant = K
K = ΔL/S
JUST NOTICEABLE DIFFERENCE
The smallest change in the intensity of a stimulus that we can detect, 75% of the time. Internet says 50%.
Also called Limen (ΔL)
SIGNAL DETECTION THEORY
Theory regarding how stimuli are detected under different conditions. Random or meaningful patterns.
David Green and John Swets (1966)
Response biases, signal-to-noise ration.
Possible responses-
Signal yes: true positive, false negative
Signal no: false positive, true negative.
MCGURK EFFECT
We integrate visual and auditory information when processing spoken language.
Audio = Ba
Visual = Ga
We hear “Da”
SYNESTHEIA
A condition in which people experience cross-modal sensations.
Hearing colours, etc.
Sir Francis Galton, 1880.
PARALLEL PROCESSING
The ability to attend to many sense modalities simultaneously.
BOTTOM-UP PROCESSING
Processing in which the whole is constructed from parts.
→ Perceiving an object on the basis of it’s edges.
→ Begins with activity in the primary visual cortex followed by association cortex.
Also known as data driven processing.
TOP-DOWN PROCESSING
Conceptually driven processing influenced by expectations and beliefs.
→ association then visual cortex.
Use of context.
PERCEPTUAL SETS
Set formed when expectations influence perceptions.
→ Young or old woman cartoon thing.
We expect to see something. Perception is an active process.
PERCEPTUAL CONSTANCY
Process by which we perceive stimuli consistently across varied conditions.
→ shape, size, colour.
SELECTIVE ATTENTION
Process of selecting one sensory channel and ignoring or minimising the others.
- reticular activating system.
- forebrain
Donald Broadbent - dichotic listening.
IN-ATTENTIONAL BLINDNESS
Failure to detect stimuli that are in plain sight when our attention is focused elsewhere.
- video with the guy dressed as a bear.
SUBLIMINAL INFORMATION PROCESSING
Subliminal perception
→ processing of sensory information below the limen (level of conscious awareness).
Subliminal persuasion = not effective.
HUE
Colour of light.
- white reflects all light, absorbs none.
- black absorbs all light, reflects none.
ADDITIVE MIXING
Mixing light.
All = white
Red, green, blue
SUBTRACTIVE MIXING
Mixing pigment.
All = black
Yellow, cyan, magenta.
SCLERA
Sclera = whites of eyes.
IRIS
Coloured bit of eyes. Controls how much light enters the eye.
PUPIL
Circular hole though which light enters the eye.
Closes when light increases or objects are coming towards us = pupillary reflex.
Dilated pupils = more attractive.
CORNEA
Part of the eye containing transparent cells that focus light on the retina.
Curved transparent layer covering the iris and pupil.
Doesn’t move or change.
LENS
Part of the eye that changes curvature to keep images in focus.
- transparent cells.
ACCOMMODATION (LENS)
Lens shape changes.
Flat = distant
Fat = close
MYOPIA AND HYPEROPIA
Myopia = nearsighted. Cornea too curved. Can see close, but not far. Hyperopia = opposite.
RETINA
Membrane at the back of the eye responsible for converting light into neural activity.
- some say actually part of the brain.
FOVEA
Central portion of the retina