UNIT 7: Sensation and perception Flashcards
transduction
The process of converting one form of energy into another that your brain can use
absolute threshold
minimum stimulation needed to detect a particular stimulus (light, sound, pressure, taste or odour) 50% of the time
‘just noticeable difference’
the minimum difference a person can detect between any two stimuli half of the time
Weber’s Law
principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage
Different thresholds
increase in proportion to the size of the stimulus. When stimulation is unchanging, you become less sensitive to the stimulus
sensation adaptation
diminished sensitivity as a consequence of constant stimulation. When we are constantly exposed to a stimulus that does not change, we become less aware of it because our nerve cells fire less frequently
sensation
the process by which our sensory receptors and nervous system receive and represent stimulus from our environment
Perception
the process of organising and interpreting sensory information, enabling us to recognise meaningful objects and events.
Bottom up processing
analysis that begins with the sensory receptors and works up to the level of the brain
- relies on sensation over perception
Top down processing
information processing is guided by higher-level mental processes, as we construct perceptions, drawing on our experience and expectations
-prone to bias (jumping to conclusion)
- occurs when you use prexisting knowledge
-perception over sensation
‘selective attention’
focusing intently on one task
inattentional blindness
when we become unaware of other visual stimulus around us
change blindness
failing to notice changes in the environment
-EX: when we are watching a magician’s left hand we fail to notice him changing cards with his right.
VISUAL
cocktail party effect
Think about trying to listen to your friend talking in the lunch queue - do you hear other people’s conversations, are you aware of everything else around you. Probably not because you are concentrating on one thing
AUDITORY
Wavelengths
the distance from the peak of one light or sound, to the peak of the next.
Lens
the transparent structure behind the pupil that changes shape to help focus images on the retina
Retina
ight sensitive inner surface of the eye, containing the photoreceptor rods and cones plus layers of neurons that begin the processing of visual information
Fovea
the central focal point in the retina, around which the eyes cones cluster
Optic (visual) Nerve
the nerve that carries neural impulses from the eye to the brain
Blind spot
the point at which the optic nerve leaves the eye, creating a blind spot because no receptor cells are located there
Cornea
protects the eye and bends light to provide focus
Rods
retinal receptors that detect black, white and gray. They are necessary for peripheral and dim-light vision. Rods share bipolar cells: sending combined messages
Cones
retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and enable you to perceive colour. In dim-light they become ineffectual
transmits to a single bipolar cell that relays the cone’s individual message to the visual cortex
Near sighted
too much curvature (via accommodation) of the lens focuses the image in front of the retina so nearby objects are seen more clearly than distant objects
Far sighted
too little curvature of the lens (via accommodation) focuses the image behind the retina so distant objects are seen more clearly than nearby ones
Young-Helmholtz trichromatic (3-colour theory)’.
the retina contains 3 different colour receptors (cones), each one especially sensitive to 1 of the 3 colours
When we stimulate combinations of these cones, we see other colours
Colorblind
lack a functioning red or green, or both sensitive cones
Monochromatic (one-colour)
Only 1 color
Dichromatic (two-colour)
2 colors
opponent-process theory.
the way humans perceive colors is controlled by three opposing systems
Afterimages
sense experiences that occur after a visual stimulus has been removed
come from looking at one color for a long period, which causes those receptor cells to become fatigued
Prosopagnosia (Face Blindness)
damage leads to an interruption of different aspects of the face-recognition process. The person has difficulty or cannot recognise other peoples faces, and even their own
Caused by damage to the occipital lobe
Blindsight
visual information from the eye is being processed unconsciously, so people with blindsight don’t know that they are visually processing.
Gestalt psychologist
