-Two Types: Anatomical Coding, Temporal Coding
Anatomical Coding: A means by which the nervous system represents information; different features
are coded by the activity of different neurons.
-Different neurons of the body code for different senses (i.e. the eye neurons will only send sight
information to the brain, and no other sensory information. The brain knows if eye neurons are
stimulated, the information being sent is sight information.)
Temporal Coding: A means by which the nervous system represents information; different features are
coded by the pattern of activity of neurons.
-Firing faster or slower indicates the strength of a stimulus
-Faster firing = Stronger
-Slower Firing = Weaker
(e.g. Touch) Firing of a particular set of neurons tells what part of the body is being touched. Firing rate
indicates strength of the touch.
Psychophysics ± A branch of psychology that measures the quantitative relation between physical
stimuli and perceptual experience.
The Principle of Just Noticeable Difference:
Just Noticeable Difference (JND) ±The smallest difference between to similar stimuli that can be
distinguished. Also called threshold.
Î Example: going to the optometrist and they flip the lenses and ask you which lens is better they
keep going until the point where you cannot notice a difference anymore. Another example is
looking at an object while it gets brighter and brighter.
Weber Fraction ±The ratio between a just-noticeable difference and the magnitude of a stimulus;
reasonably constant over the middle range of most stimulus intensities.
Weber Æ Measured the JND of people
-People could only distinguish weights different in weight by a factor of 1/40. (e.g. 40 from 41, 80 from
-Brightness of white light by a factor of 1/60.
-Known as Weber fractions.
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-Each time a difference in intensity of a stimulus was detected = 1 JND.
(1)-The ability to detect differences (JND) decreases as the intensity of the stimulus increases.
-B/c more energy is required to distinguish between stimuli of higher intensity.