Chapter 6 Flashcards
Sensation
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
Sensory Receptors
sensory nerve endings that respond to stimuli.
Perception
the process by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.
Bottom-Up Processing
starts at your sensory receptors and works up to higher levels of processing.
Top-Down Processing
constructs perceptions from this sensory input by drawing on your experience and expectations.
Transduction
Conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, smells, into neural processes our brain can interpret.
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 stimulus energy needed to detect a particular stimulus 50 percent of the time. Can be affected by our mental state.
Signal Detection Theory
A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes there is no single absolute threshold, and that detection depends partly on a person’s experience, expectations, motivations, and alertness.
Subliminal
below one’s absolute threshold for conscious awareness.
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.
Webers 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 stimulation. This occurs because our nerve cells fire less frequently.
Perceptual Set
a mental predisposition to perceive one thing and not another.
The Effectors of Perception
Context, Emotion, and Motivation
Wavelength
the distance from the peak of one light or sound wave to the peak of the next.
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.
Wavelength and Hue Relationship
Short wavelength equals high frequency (bluish colors)
Long wavelength equals low frequency (reddish colors)
Intensity
the amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height). Great amplitude equals bright colors and vice versa.
Cornea
bends light to help provide focus.
Pupil
a small adjustable opening.
Iris
a colored muscle that dilates or constricts in response to light intensity, surrounding the pupil and controlling its size. Each iris is so distinctive that iris-screening technology can often confirm identity. The iris can also respond to emotional states.
Lens
a transparent structure that focuses light rays into an image on the retina by using accommodation.
Retina
the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information. Can detect pressure, but brain perceives it as light.