Showing papers on "Summation published in 1968"
TL;DR: In this article, the difference between the energy required for a single vibrator, in dB, to reach a threshold and the energy needed for two vibrators presented successively to reach threshold was taken as the measure of probability summation.
Abstract: By means of a two-interval, forced-choice technique, absolute thresholds were obtained at several sites on the skin for short bursts of mechanical vibration. The difference between the energy required for a single vibrator, in dB, to reach threshold and the energy required for two vibrators presented successively to reach threshold was taken as the measure of probability summation. Spatial summation was computed as the difference between the energies required for threshold for the two vibrators presented successively and simultaneously. Both probability summation, 0.52 dB lowering in threshold, and spatial summation, 1.94 dB lowering in threshold, remained constant as a function of the distance between the two vibrators on the thigh. Similar amounts of summation were obtained unilaterally and bilaterally on the fingers. When the frequency of vibration was lowered to 9 Hz, no spatial summation was found. When the frequencies of vibration at the two test sites were different, 160 Hz at one locus, 360 Hz at the other locus, there was no spatial summation.
31 citations
TL;DR: In this article, the concept of linear spatial integration, embodied in Ricco's law, has been extended to situations involving inhibitory interactions, and spatial interactions affecting the perceived brightness and darkness of single, low contrast lines were examined for linearity.
23 citations
TL;DR: In this article, six Ss were presented monaurally and binaurally with stimuli of 0.5, 2.0, and 4.0 kHz at 40 and 70 dB sensation levels.
Abstract: Six Ss were presented monaurally and binaurally with stimuli of 0.5, 2.0, and 4.0 kHz at 40 and 70 dB sensation levels. Their computer averaged evoked potentials indicated substantially larger amplitudes (N1 -P2) with bilateral stimulation, regardless of frequency. Stimulation at 70 dB SL gave greater responses than that to 40 dB.
5 citations
Journal Article•
1 citations
TL;DR: Repetitious activity is assumed in randomly interconnected networks of elements with spacial and temporal summation of input excitation and exponentially decaying threshold and stimulation and bounds on the period of that oscillatory activity are theoretically established, and verified by computer simulation.
Abstract: —Repetitious activity is assumed in randomly interconnected networks of elements with spacial and temporal summation of input excitation and exponentially decaying threshold and stimulation. Bounds on the period of that oscillatory activity are theoretically established, and verified by computer simulation. The dependency of such bounds on threshold and stimulation decay rates, number of inputs to each element, maximum and return values of threshold, the presence of inhibitory elements in a network, and the profile of network activity is shown.
1 citations