process by which sensory receptors (in eye, ear, etc.) receive and are
stimulated by stimulus energies from the environment.
Perception: The process of organizing and interpreting
sensory information, enabling us to recognize meaningful objects and
Bottom-up-processing: Analysis that begins with the sense
receptors and works up to the brain's processing of the information.
Top-down-processing: Information processing guided by
higher-level processes, such as our expectations.
Absolute Threshold: The minimum stimulation needed to
detect a particular stimulus 50% of the time.
Signal Detection Theory: Predicts how and when we detect
faint stimuli (dependent on experience, expectations, motivation &
Subliminal Stimulation: Stimulation below one's threshold
of conscious awareness. Research reveals a subtle, fleeting effect on
thinking, but no effect on behavior.
Difference Threshold: The minimum difference between
two stimuli required for detection 50% of the time. It is also
called the just noticeable difference or JND. It is
based on Weber's Law: The difference threshold is in proportion
to the strength of the original stimulus.
Sensory Adaptation: Our diminishing sensitivity to
Selective Attention: The focusing of attention on specific
stimuli, while ignoring other stimuli (e.g., the cocktail party effect).
Transduction: The transforming of stimulus energies (i.e.,
light waves, sound waves) into neural impulses.
VISION & LIGHT ENERGY
Wavelength: Distance from the peak of one light or sound wave
to the next. Wavelength determines HUE or color in vision
and Pitch in audition.
Shorter wavelengths are bluish in
color, while longer wavelengths are reddish.
Amplitude: The height of a light or sound wave. It
determines brightness in vision and loudness in hearing.
Pupil: Adjustable opening in the center of the eye through which
Iris: A ring of muscle tissue that forms the colored part of the
eye. It controls the size of the pupil
Lens: The transparent structure behind the pupil that changes
shape (called accommodation) to help focus images on the retina.
Visual Acuity: The sharpness of vision.
Nearsightedness: Can see
nearby objects more clearly because distant object focus in front of the
retina (eyeball may be too long).
Farsightedness: Can see
distant objects more clearly because nearby objects focus behind the
retina (eyeball may be too short).
Rods & Cones: The receptor cells for vision.
Receptor cells are specialized neurons designed, in this case, to
transduce light energy into neural impulses.
Rods: detect black, white, & grey. Found mainly in the
periphery of the retina. More than one rod connects to each
bipolar cell. Thus, less light energy is necessary for them to
cause the bipolar cells to fire. Necessary for NIGHT VISION &
Cones: Found mainly in the center (fovea) of the retina.
Necessary for COLOR VISION and VISUAL ACUITY.