Chapter 4 Flashcards
Sensation and Perception
Sensation
Simple stimulation of a sense organ. (Basic registration of light, sound, pressure, odor, or taste).
Perception
Organization, identification, and interpretation of a sensation in order to form a mental representation.
Transduction
The process whereby senses receptors convert physical signals from the environment into neural signals that are sent to the central nervous system.
Sensory Adaptation
The process whereby sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current (unchanging conditions).
Psychophysics
Methods that systematically relate the physical characteristics of a stimulus to an observer’s perception.
Absolute Threshold
The minimal intensity needed to just barely detect a stimulus in 50% of the trials.
Sensitivity
How responsive we are to faint stimuli.
Acuity
How well we distinguish two very similar stimuli.
Just Noticeable Difference (JND)
The minimal change in a stimulus (e.g., in its loudness or brightness) that can just barely be detected.
Weber’s Law
For every sense domain, the change in a stimulus that is just noticeable is a constant proportion of the standard stimulus, over a broad range of intensities.
Signal Detection Theory (SDT)
A way of analyzing data from psychophysics experiments that measure an individual’s perceptual sensitivity while also taking notice, expectations, motivations, and goals into account.
Decision Criterion
The strength of the sensory evidence for the stimulus, and the amount of evidence necessary for your perceptual system to “decide” that the stimulus is present.
Cornea
Clear smooth outer tissue that bends light wave and sends it through the pupil.
Pupil
A hole in the colored part of the eye
Iris
Colored part of the eye, a translucent, doughnut-shaped muscle that control the size of the pupil and the amount of light that enters the eye.
Retina
A layer of light-sensitive tissue lining the back of the eyeball.
Accommodation
The process by which the eye maintains a clear image on the retina.
Cones
Photoreceptors that detect color, operate under normal daylight conditions, and allow us to focus on fine details.
Rods
Photoreceptors that become active only under low-light conditions, for night vision.
Fovea
An area of the retina where vision is clearest and there are no rods at all
Blind Spot
A location in the visual field that produces no sensation on the retina.