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Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Five rhesus macaques monkeys surgically prepared with Thiry small intestinal (jejunum) loops and implanted brain electrodes were restrained in primate chairs and kept on 23‐hr deprivation‐feeding cycle. After being trained to press a lever for sugar pills on an FR 25 schedule of reinforcement, a discrimination training procedure was established. Lever presses were reinforced during the SD—a non‐aversive mechanical stimulus applied to the internal walls of the Thiry loop by rhythmic inflation‐deflation of a small latex balloon by air at the rate of one cycle per sec at 100 mm Hg pressure. The SΔ was the absence of the visceral stimulation. The monkeys successfully discriminated between presence and absence of the internal stimulus. A discrimination reversal was attempted and completed on one monkey. The results clearly show operant discrimination based on an interoceptive stimulus. Cortical and subcortical EEG records reflected the onset but not termination of the visceral stimulation.

A rat was trained on a schedule that programmed reinforcements only when a minimum waiting time between successive responses was exceeded (DRL schedule). It was observed to fill much of the pause between lever presses with a stereotyped behavioral chain: it would take its tail in its mouth and nibble it. This behavior was shown to be functionally related to the efficiency with which the subject spaced its responses. It is thought to have served as mediating behavior, providing discriminating stimuli for appropriate lever presses.

Because the response and time scales used in plotting cumulative response curves are often poorly selected, ineffective displays often result. The visual cue of a response rate change is the difference, Δθ, between the angles, θ1 and θ2, representing the two rates, R1 and R2. These variables are related by: tan θ2 = R2/R1 tan θ1. For a given rate change, the value of θ1, namely, Mθ1, that yields the maximum value of Δθ, namely, Δθmax, is given by Mθ1 = arc sin. Ideally, the initial response rate should be represented by the Mθ1 appropriate for a given rate change. Because of practical considerations, however, some compromises with the ideal are allowable. Included in the discussion are (a) steps required to select appropriate response and time scales, with examples, and (b) guideposts for evaluating rate changes by means of angular changes.

Two pigeons were trained with positive reinforcement on a multiple FR VI 2 schedule. The VI 2 component was held constant while the FR component was changed from ratios of 1 to 300. After responding had stabilized at each FR value, VI responses produced briefly either the fixed‐ratio SD or a stimulus uncorrected with either schedule component. Compared to the effects of the uncorrected stimulus change, the fixed‐ratio SD produced a decrease in VI responding proportional to the size of the FR requirement. It is concluded that stimuli associated with high FR schedules served as punishment for the ongoing behavior.

The relationship between punishment shock intensity and basal skin resistance (BSR) was investigated in two sessions with human females selected for their ability to maintain a fairly substantial operant rate under a wide range of shock intensities. In both sessions each button‐pressing response was reinforced with a counter tally. Subjects were paid one cent for each 20 counts. In session 1, punishment followed each response during alternate 4‐min periods; in session 2 punishment was programmed in all 4‐min periods. Shock intensities were presented randomly among the 4‐min shock periods, with the restriction that the first three presentations occurred in ascending order. Operant responding showed some suppression at higher shock intensities in session 1, with substantial recovery in most subjects during session 2. Respondent behavior was characterized by greater activity at successively higher intensities, with recovery at all shock levels, especially the lowest levels, apparent during the second session.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.