The magical number seven: Making a “bit” of “sense”

The psychophysics of taste from the entropy of the stimulus

“…This deviation from linearity is seen very clearly in most of the experimental graphs for taste given by Stevens (1969). Equation 9 was derived by Norwich (1977Norwich ( , 1981a with reference to electrical activity in sensory neurons.…”

“…The corresponding value of channel capacity for sucrose measured by Beebe-Center, Rogers, and O'Connell (1955) 13 describes the progressive fall in magnitude estimate, F, with time, t. By curve-fitting the data from experimental adaptation curves to the function given by Equation 13, we can evaluate the constants k and B, and hence, by the method described earlier (Norwich, 1981a), measure the information transmitted per taste stimulus.…”

“…matiori is gradual, as shown by the curve in Figure 1. The difference between the amplitudes of the step and the curve in the graph in Figure 1 is a declining curve, which traces the progressive reduction in uncertainty and describes the process of adaptation to the stimulus (Norwich, 1981a). When the entropy function, H, is evaluated for a steady stimulus of mean intensity, Il, applied to a sensory receptor for a time duration, t, and this function is introduced into Equation 1, we obtain (Norwich, 1977(Norwich, , 1981a (for "oc" read "varies as" or "is proportional to").…”

“…When the entropy function, H, is evaluated for a steady stimulus of mean intensity, Il, applied to a sensory receptor for a time duration, t, and this function is introduced into Equation 1, we obtain (Norwich, 1977(Norwich, , 1981a (for "oc" read "varies as" or "is proportional to"). Since the stimulus magnitude, in this case, is the concentration of a solution, the value of the exponent, The factor Il n entered Equation 2 from the physical relationship between the mean and variance of a stimulus (Norwich 1977(Norwich , 1981a, Replacing (YzknA)"l by the single constant, 0, we have If we associate AF with the small change in magnitude estimate corresponding to one just noticeable difference in perceived intensity, Equation 10 will be a general expression for the Weber fraction.…”

“…Since stimuli of greater intensity exhibit greater fluctuations about the mean, the resolvable uncertainty (or transmissible information, or entropy), H (bits), as well as the neural response, F (impulses/second), will also be greater. The fundamental hypothesis of the entropy view of perception (Norwich, 1977(Norwich, , 1981a is that neural response is related to stimulus entropy by means of the equation…”