Model Of Rivalry Research Articles

A physiological model of binocular rivalry

This paper presents a modified reciprocal inhibition model for the temporal dynamics of binocular rivalry. The model is based on neurophysiological mechanisms and is derived from human psychophysical data. A simple reciprocal inhibition oscillator may be described with a set of four coupled differential equations with a neurophysiological interpretation. However, such a circuit does not account for some aspects of the temporal behavior of binocular rivalry, including the effects of contrast change on alternation rate and on the magnitudes of changes in duration of the suppressed and dominant phases. To better account for these phenomena, the equations and their stimulation are modified to include three new components: (1) presynaptic inhibition of the reciprocal inhibition by the input, (2) the motor delays that occur when a human observer tracks rivalry and (3) a minimum threshold for each neuron's state variable. The result is a much improved fit to psychophysically-obtained data on the temporal behavior of binocular rivalry. Finally, the model is incorporated into a larger model to suggest how rivalry might occur in a network that usually exhibits binocular fusion.

An astable multivibrator model of binocular rivalry.

The behavior of a neural network model for binocular rivalry is explored through the development of an analogy between it and an electronic astable multivibrator circuit. The model incorporates reciprocal feedback inhibition between signals from the left and the right eyes prior to binocular convergence. The strength of inhibitory coupling determines whether the system undergoes rivalrous oscillations or remains in stable fusion: strong coupling leads to oscillations, weak coupling to fusion. This implies that correlation between spatial patterns presented to the two eyes can affect the strength of binocular inhibition. Finally, computer simulations are presented which show that a reciprocal inhibition model can reproduce the stochastic behavior of rivalry. The model described is a counterexample to claims that reciprocal inhibition models as a class cannot exhibit many of the experimentally observed properties of rivalry.

Binocular rivalry with rotary and radial motions.

Binocular rivalry between a radially sectored and a concentrically circular pattern was investigated in three experiments. Motion of the circular pattern was either cyclical expansion and contraction with corresponding changes in spatial frequency (experiment 1), or outward motion with a constant linear velocity (experiment 2). When both patterns were static the circular pattern was visible for longer than the radial one. Motion of either pattern alone resulted in an increase in the predominance duration and the mean period for which the pattern was visible. This is at variance with Levelt's model of rivalry. In the third experiment, rivalry was between a static circular pattern and a radial pattern that could be rotated at different angular velocities. Again it was found that an increase in stimulus strength, as measured by predominance, led to an increase in the mean periods of visibility of the rotating pattern.

The dynamic model of binocular rivalry.

Binocular rivalry is an interesting phenomenon observed in the human vision. It occurs when the right and left eyes are given different stimuli (pictures). This paper describes a mathematical model which explains the mechanism of binocular rivalry. Our basic assumption is that binocular rivalry is elicited by the mutual inhibition between the right and left visual neuron systems. The mutual inhibition between two neurons is first discussed in detail, where a special emphasis is put on a fatigue effect of neurons, and then its results are applied to a simulation model of binocular rivalry.

Binocular rivalry and semantic processing: out of sight, out of mind.

Previous studies of binocular rivalry have shown that some aspects of a phenomenally suppressed stimulus remain available for visual analysis. The question remains, however, whether this analysis extends to the case of semantic information. This experiment examines that question using a semantic-priming paradigm in which prime words were briefly flashed to an eye during either dominance or suppression phases of binocular rivalry. Reaction times on a lexical-decision task were significantly shortened (the semantic-priming effect) only when prime words were presented to an eye during dominance; suppression acted to impair word recognition and to eliminate semantic priming. These results are inconsistent with certain cognitive models of binocular rivalry.

Neural models of brightness perception and retinal rivalry in binocular vision

In binocular fusion, pairs of left and right stimuli yielding the same brightness perception constitute an equibrightness curve in a coordinate system whose ordinate and abscissa correspond to left and right stimulus strengths. A neural network model is presented to elucidate the characteristics of the curve. According to the model, Fechner's paradox is due to the threshold characteristics of the neuron. If the shapes or movements are radically different between the left and right stimuli, the retinal rivalry is caused. That is, only the left stimulus is perceived at one moment and the right stimulus at another moment. The period of left or right eye dominance alternates randomly from time to time. The distribution of the period is approximate to the gamma distribution. In order to account for this fact, a neural network model is proposed, which consists of a pair of neurons receiving inputs with stochastic fluctuations. The computer simulation was carried out with satisfactory results. The model of retinal rivalry is integrated with that of brightness perception.

Threshold conditions for binocular rivalry.

A series of three experiments was performed to determine the minimum contrast necessary for a grating pattern to engage in binocular rivalry with a dissimilar pattern presented to the other eye. It was found that a pattern at its own contrast threshold can suppress temporarily a contralateral pattern, regardless of the contrast of the latter. In a fourth experiment it was found that a near-threshold pattern is as effective, in terms of the duration of visibility, as one that is four times greater in contrast; only the average duration of suppression varied with pattern contrast. This last set of data extends the findings of others to near-threshold conditions and poses difficulties for models of binocular rivalry based on the notion of reciprocal inhibition.

FCC Regulation, Monopsony, and Network Television Program Costs

In this paper, a television program cost function is derived from a simple model of network rivalry based upon the Cournot postulate. This cost function is then fitted to data from a cross section of new network entertainment series for 1960-1965. The resulting estimates are quite unfavorable to two different aspects of FCC policy towards television broadcasting.