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Data were obtained on the spectral sensitivity of the light-adapted monkey by two operant conditioning techniques adapted to use with brief duration stimuli: cued avoidance conditioning, and a positive reinforcement-reaction time method. The results are compared with human photopic spectral sensitivity, and detailed similarities are found.

A random ratio schedule is one under which every ordinally specified response has the same probability of reinforcement as any other. Data have been gathered at several values of this type of schedule, using a separate group of pigeons for each schedule value and giving prolonged exposure to each value. No simple relationship was found between response rate and reinforcement probability. In general aspect group data from the present experiment agree with those from a single organism study cited. It was shown that 40 to 50 days of exposure to random ratio schedules yields fairly asymptotic response rate data. The tabulated raw data, and the results of some statistical manipulations, have been deposited with the American Documentation Institute.

Measurements are reported for four White Carneaux pigeons (10-13 yr old) of induced current flow, through chronic pubis electrode implants, as a function of the two shock parameters, intensity and pulse frequency. METHODElectrodes of #20 gauge gold-on-copper wire were tied around the pubis bones of the birds (Azrin, 1959). Two birds (#19 and #21) were prepared 15 months before the data were obtained, and the other two (#5 and #11) were prepared 3 hr prior to the first set of measurements, to determine the effects, if any, of the formation of scar tissue or other by-products of chronic implants.A monitored constant-voltage transformer supplied 60 cycle AC across a precision resistance in series with the bird, and the voltage drop across the resistor was read from a calibrated oscilloscope. The voltage drop across the bird and the current flow were calculated using Ohm's law. At each voltage, the bird was exposed to a train of ten, 60-millisec duration pulses at a rate of 1 per sec, followed by approximately a 90-sec "rest" before the next voltage test level was applied. Voltage across the bird was varied in 15 approximately equal steps from 4 volts to 80 volts peak-to-peak. Each bird was exposed to an ascending (low to high) and a descending series of the voltages used, in that order, and following each series a redetermination of the initial value in that series was made, pauses between series and redeterminations being again approximately 90 sec long.Forty-eight hours after a bird had been exposed-to the voltage series, measurements of current flow were taken as a function of 'This research was supported by the National Science Foundation through grant NSF G-18633.voltage pulse frequency. During the pulse frequency measurements, the total voltage (across the resistor plus the bird) was held constant at 50 volts peak-to-peak. Pulse frequency was varied in 10% steps from 1 pulse per 3.0 sec to 1 pulse per 0.3 sec. At each pulse frequency, a train of 10 square pulses of the 60 cycle AC was given. Intervals of approximately 90 sec separated determinations. An ascending (slow to fast) and a descending series were used, and the initial values were redetermined at the end of each series.Seventy-two hours after the pulse frequency measurements were made, a new series of voltage measurements was begun. During this series, the voltage was impressed continuously, without "rests" between voltage test levels, and varied in approximately 7-volt steps from 5 to 35 volts peak-to-peak across the bird. RESULTSThe relationship between the voltage across and the current flow through the birds for the range of impressed voltages used is closely linear. Regression equations2 fitted to the data (I in amps) by the method of least squares are, for

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