lesson 5 Flashcards
Sensation
Simple stimulation of a sense organ
Perception
Organization, identification, and interpretation of a sensation in order to form a mental representation
Synesthesia
Perceptual experience of one sense that is evoked by another sense
Transduction
What takes place when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
Psychophysicists
Often measure the minimum amount of a stimulus needed for detection
Psychophysics
Methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus
Absolute threshold
Minimal intensity needed to just barely detect a stimulus
Just noticeable difference (JND)
Minimal change in a stimulus that can just barely be detected
Weber’s Law
JND of a stimulus is a constant proportion despite variations in intensity
Signal detection theory
Response to a stimulus depends both on the person’s sensitivity to the stimulus in the presence of noise and on a person’s response criterion; takes into account individual perceptual sensitivity
Sensory adaptation
Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions
Visual acuity
Ability to see fine details
Visible light
Portion of electro magnetic spectrum seen
length
determines color
Intensity / amplitude
determines brightness
Purity
Corresponds saturation or richness of colour
Accommodation
Process by which the eye maintains a clear image on the retina
Retina
Light‐sensitive tissue lining the back of the eyeball
Cones
Detect colour, operate under normal daylight conditions, and allow us to focus on fine details
Fovea
Area of the retina where vision is the clearest and there are no rods at all (only cones)
Rods
Become active under low‐light conditions for night vision
Retina
Layers of cells including the bipolar cells and the retinal ganglion cells (in addition to the rod and cone layers)
Blind spot
Location in the visual field that produces no sensation on the retina because the corresponding area of the retina contains neither rods nor cones and therefore has no mechanism to sense light
Receptive field
Region of the sensory surface that, when stimulated, causes a change in the firing rate of that neuron
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