Chapter 5: Sensation Flashcards
Perception
The process of organizing & interpreting sensory info, enabling us to recognize meaningful objects & events.
Sensation
The process by which our sensory receptors & nervous system receive & represent stimulus energies from our environment.
Bottom-up processing
Analysis that begins with the sensory receptors & works up to the brain’s integration of sensory info.
Top-down processing
Info processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience & expectations.
Psychophysics
The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.
Absolute threshold
The minimum stimulation needed to detect a particular stimulus 50% of the time. (Light, sound, pressure, taste or odor)
Signal detection theory
A theory predicting how & when we detect the presence of a faint stimulus (“signal”) amid background stimulation (“noise”). Assumes there is no single absolute threshold & that detection depends partly on a person’s experiences, expectations, motivation & level of fatigue.
Subliminal
Below one’s absolute threshold for consciousness awareness.
Priming
The activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory or response.
Difference threshold
The minimum difference between 2 stimuli required for detection 50% of the time. We experience the difference threshold as a just noticeable difference.
Weber’s Law
The principle that to be perceived as different, 2 stimuli must differ by a constant minimum percentage (rather than a constant amount)
Sensory adaption
Diminished sensitivity as a consequence of constant motion.
Transduction
Encode physical energy as neural signals.
Wavelength
The distance from the peak of one light or soundwave to the peak of the next
Hue
The dimension of color that is determined by the wavelength of light
Intensity
The amount of energy in a light or soundwave, which we perceive as brightness of loudness, as determined by the wave amplitude.
Pupil
The adjustable opening in the center of the eye through which light enters.
Iris
A ring of muscle tissue that forms the colored portion of the eye around the pupil & controls the size of the pupil opening.
Lens
The transparent structure behind the pupil that changes shape to help focus images on the retina.
Accommodation
The process by which the eye’s lens changes shape to help focus images on the retina.
Retina
The light-sensitive inner surface of the eye, containing the receptor rods & cones plus layers of neurons that begin processing visual info.
Acuity
The sharpness of vision