Chapter 5 sensation Flashcards
Perception
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
Sensation
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
Bottom-up prossesing
analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information
Top-down prossesing
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and 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 percent of the time.
Single-detection theory
a theory predicting how and when we detect the presence of a faint stimulus (“signal”) amid background stimulation (“noise”). Assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and level of fatigue.
Subliminal
below one’s absolute threshold for conscious awareness.
Priming
the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response.
Difference threshold
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. (Also called just noticeable difference or jnd.)
Weber’s law
the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).
Sensory adaptation
diminished sensitivity as a consequence of constant motion.
Transduction
conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.
Wavelength
the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission.
Hue
the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.4
Intensity
the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude.
Pupil
the adjustable opening in the center of the eye through which light enters.
Iris
a ring of muscles tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.